Method for determining stability of deep-sea anchor pile and main control influencing factor of mooring parameter

Abstract

The application provides a deep-sea anchor pile stability determination and mooring parameter main control influence factor determination method, relates to the deep water mooring technical field of ocean engineering, and first explains the physical phenomenon that the load centering type anchor pile has "double embedded ends" and "invalid area", and proposes a set of method for identifying the embedded end position by solving the differential equation in sections, so as to accurately divide the effective stress area, only integrate the soil reaction force of the effective area, and obtain accurate bearing capacity calculation results. This not only solves the theoretical deviation of the existing method, but also greatly reduces the design and construction cost of the deep-sea anchor pile under the premise of ensuring the safety of the project, and has great engineering application value. The application also provides a deep-sea anchor pile stability determination scheme, a verification device, a verification scheme and a mooring parameter main control influence factor determination scheme, solves the theoretical deviation of the existing method, greatly reduces the design and construction cost under the premise of ensuring the safety of the project, and has remarkable engineering application value.

Description

Technical Field

[0001] This invention relates to the field of deep-water mooring technology in marine engineering, and in particular to a method for determining the stability of deep-sea anchor piles and the main influencing factors of mooring parameters. Background Technology

[0002] As global oil and gas resource development moves towards deeper waters, floating offshore engineering equipment such as Floating Production Storage and Offloading (FPSO), semi-submersible platforms, and tension leg platforms are widely used. As the core foundational component of deep-water mooring systems, anchor piles play a crucial role in transmitting wind, wave, and current loads on the floating platform and maintaining its overall positional stability. Their load-bearing capacity and stability directly determine the safety and economy of the entire deep-water oil and gas development project. In tensioned mooring systems, anchor piles primarily bear the lateral tension and vertical components transmitted by the mooring cables; the interaction between the pile and the seabed soil is the core mechanism for the formation of its load-bearing capacity.

[0003] In existing technologies, the calculation of the lateral bearing capacity of anchor piles is mostly based on simplified models constructed using the Euler-Bernoulli beam theory and the Winkler foundation assumption. Current design methods generally treat the pile bottom as a fully embedded fixed boundary, or estimate the soil reaction coefficient using empirical formulas to calculate the internal forces and displacements of the pile. These methods can meet the engineering accuracy requirements in the design of short, thick piles in shallow seas. However, as water depth increases, the length-to-diameter ratio of the anchor pile increases significantly, and the pile body exhibits obvious flexible deformation characteristics under lateral loads. The traditional assumption of "fully embedded pile tip" deviates considerably from the actual stress state and can no longer accurately reflect the true stress and deformation patterns of anchor piles in deep-sea soft soil foundations.

[0004] Specifically, existing deep-sea anchor pile design and stability assessment technologies have the following five significant shortcomings: 1. Lack of systematic methods for identifying embedded ends: Existing technologies cannot systematically determine whether anchor piles have formed embedded ends under lateral loads, nor can they distinguish between different stress states of 0, 1, or 2 embedded ends, resulting in a lack of core theoretical basis for anchor pile stability assessment.

[0005] 2. Inability to accurately quantify the stress zone: Existing technology makes it difficult to accurately divide the active stress deformation zone and passive static zone of the pile body, which leads to large errors in subsequent calculation of lateral bearing capacity and displacement prediction.

[0006] 3. Lack of graded stability assessment indicators: The existing design system cannot intuitively quantify the safety margin of anchor piles under different working conditions. In engineering, it is difficult to distinguish the differences between double-embedded ends (stable state), single-embedded ends (critical state) and no-embedded ends (instability state), which can easily lead to overly conservative design or insufficient safety reserves.

[0007] 4. Insufficient sensitivity analysis of main control factors: There is a lack of systematic theoretical and experimental methods to analyze the influence of the coupling effect of multiple factors such as soil stiffness, pile flexibility, load application location, and mooring angle on the formation and evolution of the embedded end. It is impossible to quantitatively identify the key design parameters that control the stability of the anchor pile, so the optimization of the anchor pile structure and mooring parameters can only rely on engineering experience, making it difficult to achieve the optimal balance between economy and safety.

[0008] 5. Incomplete targeted experimental verification system: Existing physical model experiments for anchor piles are mostly focused on ultimate bearing capacity testing. The experimental parameters are not fully covered, the monitoring methods are limited, and the data repeatability is poor. This makes it impossible to provide reliable experimental data support for the verification and correction of theoretical models, and it is also difficult to directly guide engineering practice.

[0009] The aforementioned technical deficiencies have led to a significant lack of direction in the current design of deep-sea anchor piles. Some projects have seen a substantial increase in construction costs and difficulties due to overly conservative designs, while others have left safety hazards due to an underestimation of stability risks under complex working conditions. Summary of the Invention

[0010] This manual provides methods for determining the stability of deep-sea anchor piles and the main influencing factors of mooring parameters, in order to solve the problem that existing deep-sea anchor pile designs are largely blind, leading to difficulties in balancing construction costs, difficulty, and stability.

[0011] To address the aforementioned technical problems, this specification provides a method for determining the stability of deep-sea anchor piles, comprising: constructing a lateral deflection control differential equation for the anchor pile on the seabed for an engineering condition where mooring loads act on the middle of the anchor pile; dividing the anchor pile into an upper section and a lower section based on the point of application of the mooring load; solving the lateral deflection control differential equation segment by segment to obtain the pile displacement distribution functions for the upper and lower sections of the anchor pile; calculating and identifying the positions of the embedded ends based on the pile displacement distribution functions of the upper and lower sections of the anchor pile; the embedded ends being the points where the deflection displacement on the pile body approaches zero, excluding the pile tip; and determining the stability of the anchor pile based on the number of embedded ends.

[0012] In some embodiments, determining the stability of the anchor pile based on the number of embedded ends includes: if the number of embedded ends is two, then the anchor pile is determined to have reached the target stable state of the engineering design; if the number of embedded ends is zero, then the anchor pile is determined to be in an unstable state.

[0013] In some embodiments, when two embedded ends are identified, the method further includes: calculating the total lateral bearing capacity of the anchor pile based on the integral of the soil reaction force in the region between the two embedded ends; the formula for calculating the total lateral bearing capacity is: , Among them, F Ldenoted as the total lateral bearing capacity, x1 as the coordinate of the upper fixed end, x2 as the coordinate of the lower fixed end, and p(x) as the soil reaction force at the position x on the anchor pile.

[0014] The second aspect of this specification provides a method for identifying the embedded end position of a deep-sea anchor pile, comprising: for the engineering condition where the mooring load acts on the middle part of the anchor pile, constructing a differential equation for the lateral deflection control of the anchor pile on the seabed, and dividing the anchor pile into an upper section and a lower section based on the point of application of the mooring load, solving the differential equation for the lateral deflection control segment by segment, and obtaining the displacement distribution functions of the upper section and the lower section of the anchor pile respectively; The location of the embedded end is calculated and identified based on the pile displacement distribution function of the upper and lower anchor piles; the embedded end is the location point on the pile body where the flexural displacement approaches zero, excluding the pile end.

[0015] This specification provides a verification device for a method of determining the stability of deep-sea anchor piles in a third aspect, used to verify the method of determining the stability of deep-sea anchor piles as described in any of the first aspects; the verification device includes: an experimental test model, including multiple sets of simulated anchor piles with different geometric parameters, and a mooring system composed of anchor chains and polyester cables; an installation and environmental simulation system, including a soil box for simulating seabed soil, a vertical loading system for realizing the insertion and extraction of simulated anchor piles, and a swing motor for applying periodic loads; a data acquisition system, including soil pressure sensors and acceleration sensors deployed on the pile body of the simulated anchor piles, tension sensors deployed at both ends of the mooring cable, displacement sensors for monitoring anchor pile displacement, and a data acquisition instrument for acquiring data from all sensors; and electronic equipment for verifying the method of determining the stability of deep-sea anchor piles based on the acquired sensor data, and / or analyzing the main controlling factors of mooring parameters and determining the optimal design range of the main controlling factors.

[0016] This specification provides a verification method for determining the stability of deep-sea anchor piles in its fourth aspect, employing the verification equipment for the deep-sea anchor pile stability determination method described in the third aspect. The verification method includes: S21: After installing and calibrating sensors according to a preset experimental plan, the anchor pile is vertically pressed into the simulated seabed soil to the design depth, and the initial tension is adjusted to the design value after connecting the mooring system; S22: The data acquisition system is activated, and the swing motor is controlled to apply a preset load, continuously and synchronously acquiring soil pressure, acceleration, tension at both ends of the mooring cable, and anchor pile top displacement data at various measuring points on the pile body; S23: The acquired pile acceleration time history data is subjected to secondary integration and filtering to calculate the lateral displacement of each measuring point; the fixed end position in the static experiment is automatically identified based on the displacement criterion, or the average fixed end and peak value are identified separately in the dynamic experiment. The evolution law of the embedded end; cross-validation of the embedded end identification results using synchronously acquired earth pressure data; S24: Determine the effective stress zone of the pile body based on the identified embedded end position, and obtain the theoretically calculated lateral ultimate bearing capacity by integrating the earth pressure distribution curve within the effective stress zone; introduce the soil cyclic softening correction coefficient under dynamic working conditions to calculate the dynamic ultimate bearing capacity and the residual ultimate bearing capacity; S25: Compare and analyze the theoretical calculation results of the embedded end position and lateral bearing capacity with the experimental measurement results, calculate the relative error, and thus verify the accuracy of the deep-sea anchor pile stability determination method; replace at least one of different pile diameter, pile length, anchor hole height, mooring angle, and initial tension to form a new preset experimental scheme, and repeat steps S21-S25 to verify the universal applicability of the deep-sea anchor pile stability determination method under different parameter conditions.

[0017] In some embodiments, the steps of the static experiment include: controlling the oscillating motor to rotate unidirectionally at a slow rate less than a predetermined rate, applying a monotonically increasing quasi-static load, and collecting complete pile soil pressure and acceleration data after each load level stabilizes; identifying the static embedded end position under different loads and calculating the static ultimate bearing capacity; analyzing the influence of each parameter on the anchor pile's static embedded end position, effective stress zone range, and static ultimate bearing capacity; and / or, the steps of the dynamic experiment include: controlling the oscillating motor to periodically oscillate back and forth according to a preset frequency and amplitude to simulate periodic wave loads, pausing loading after each preset number of cycles, and collecting steady-state pile response data; identifying the average embedded end and peak embedded end positions under different number of cycles, calculating the dynamic ultimate bearing capacity and residual ultimate bearing capacity; analyzing the influence of each parameter on the anchor pile's cumulative deformation characteristics, stiffness degradation law, and embedded end evolution rate, and evaluating the anchor pile's full life-cycle service performance.

[0018] The fifth aspect of this specification provides a method for determining the main influencing factors of mooring parameters, including: S31: using the controlled variable method, conducting multiple sets of comparative experiments to control the influence of at least one of the following on the stability of the anchor pile: pile diameter, pile length, mooring anchor height, mooring angle, and initial tension, and collecting data on pile earth pressure, acceleration, mooring cable tension, and displacement for each set of experiments; S32: processing the experimental data of multiple sets of controlled variables using the verification equipment described in the third aspect, and establishing the relationship between parameters such as pile diameter, pile length, mooring anchor height, mooring angle, and initial tension and the anchor pile embedment end position, lateral bearing capacity, cumulative deformation, and stiffness degradation rate. The quantitative relationship is as follows: The embedded end position identification method of the deep-sea anchor pile described in the second aspect is used to identify the embedded end position; S33: Sensitivity analysis is used to quantify the influence of each parameter on the static stability and dynamic service performance of the anchor pile, and to identify the key control parameters for controlling the stability of the anchor pile; S34: Influence curves of each parameter on the performance of the anchor pile are plotted, and the effect of parameter changes on the formation conditions of double embedded ends, the effective stress zone range, and the bearing capacity is analyzed; S35: Based on the parameter influence law, the optimal design range of the anchor pile structure and mooring parameters under different engineering conditions is determined to guide the engineering design of deep-water mooring anchor piles.

[0019] The sixth aspect of this specification provides a device for determining the stability of deep-sea anchor piles, comprising: a construction unit for constructing a differential equation governing the lateral deflection of the anchor pile on the seabed for an engineering condition where a mooring load acts on the middle of the anchor pile, and dividing the anchor pile into an upper section and a lower section based on the point of application of the mooring load, and solving the differential equation governing the lateral deflection segment by segment to obtain the displacement distribution functions of the upper and lower sections of the anchor pile respectively; an identification unit for calculating and identifying the position of the embedded end based on the displacement distribution functions of the upper and lower sections of the anchor pile; wherein the embedded end is a position point on the pile where the lateral deflection displacement approaches zero, excluding the pile tip; and a first determination unit for determining the stability of the anchor pile based on the number of embedded ends.

[0020] The seventh aspect of this specification provides a device for identifying the embedded end position of a deep-sea anchor pile, comprising: a construction unit for constructing a differential equation governing the lateral deflection of the anchor pile on the seabed for engineering conditions where mooring loads act on the middle of the anchor pile body, and dividing the anchor pile into an upper section and a lower section based on the point of application of the mooring load, and solving the differential equation governing the lateral deflection segment by segment to obtain the displacement distribution functions of the upper and lower sections of the anchor pile respectively; and an identification unit for calculating and identifying the position of the embedded end based on the displacement distribution functions of the upper and lower sections of the anchor pile; wherein the embedded end is a position point on the pile body where the deflection displacement approaches zero, excluding the pile tip.

[0021] This specification provides a verification device for a method of determining the stability of deep-sea anchor piles in its eighth aspect, employing the verification equipment for the method of determining the stability of deep-sea anchor piles described in the third aspect. The device includes: a first control unit, used to control the vertical pressing of the anchor pile into the simulated seabed soil to the design depth after installing and calibrating sensors according to a preset experimental plan, and adjusting the initial tension to the design value after connecting the mooring system; a second control unit, used to start the data acquisition system, control the swing motor to apply a preset load, and continuously and synchronously acquire soil pressure, acceleration, tension at both ends of the mooring cable, and displacement data of the anchor pile top at each measuring point on the pile; a first data processing unit, used to perform secondary integration and filtering on the acquired pile acceleration time history data, and calculate the lateral displacement of each measuring point; automatically identify the embedded end position in the static experiment based on displacement criteria, or identify the evolution law of the average embedded end and the peak embedded end in the dynamic experiment respectively; and use the synchronously acquired soil pressure data to analyze the embedded end position. The results of the fixed-end identification are cross-validated. The second data processing unit is used to determine the effective stress zone of the pile body based on the identified fixed-end position, and to obtain the theoretically calculated lateral ultimate bearing capacity by integrating the soil pressure distribution curve within the effective stress zone. Under dynamic working conditions, a soil cyclic softening correction coefficient is introduced to calculate the dynamic ultimate bearing capacity and the remaining ultimate bearing capacity. The comparison unit is used to compare and analyze the theoretical calculation results of the fixed-end position and lateral bearing capacity with the experimental measurement results, calculate the relative error, and thus verify the accuracy of the deep-sea anchor pile stability determination method. The scheme update unit is used to replace at least one of different pile diameters, pile lengths, anchor hole heights, mooring angles, and initial tensions to form a new preset experimental scheme, so that the first control unit, the second control unit, the first data processing unit, the second data processing unit, and the comparison unit can be repeatedly executed to verify the universal applicability of the deep-sea anchor pile stability determination method under different parameter conditions.

[0022] The ninth aspect of this specification provides a device for determining the main influencing factors of mooring parameters, comprising: a third control unit, used to conduct multiple sets of comparative experiments on the influence of at least one of pile diameter, pile length, mooring anchor height, mooring angle, and initial tension on the stability of the anchor pile using the controlled variable method, and to collect data on pile soil pressure, acceleration, mooring cable tension, and displacement of each set of experiments; a third data processing unit, used to process the experimental data of multiple sets of controlled variables through the verification equipment described in the third aspect, and to establish a quantitative relationship between parameters such as pile diameter, pile length, mooring anchor height, mooring angle, and initial tension and the anchor pile embedment end position, lateral bearing capacity, cumulative deformation, and stiffness degradation rate; wherein the embedment end position identification method of the deep-sea anchor pile described in the second aspect is used to identify the embedment end position; and a fourth data processing unit, used to quantify the influence of each parameter on the static stability and dynamic service performance of the anchor pile using a sensitivity analysis method, and to identify the key main control parameters controlling the stability of the anchor pile. The analysis unit is used to plot the influence curves of various parameters on the performance of the anchor pile, and to analyze the effect of parameter changes on the formation conditions of double-embedded ends, the effective stress zone range, and the bearing capacity. The second determination unit is used to determine the optimal design range of anchor pile structure and mooring parameters under different engineering conditions based on the parameter influence law, so as to guide the engineering design of deep-water mooring anchor piles.

[0023] This specification provides a tenth aspect of an electronic device, comprising: a memory and a processor, wherein the processor and the memory are communicatively connected to each other, the memory stores computer instructions, and the processor executes the computer instructions to implement the method of any one of the first aspect, the second aspect, the fourth aspect, and the fifth aspect.

[0024] The eleventh aspect of this specification provides a computer storage medium storing computer program instructions, which, when executed by a processor, implement the steps of the above-described method for determining the stability of deep-sea anchor piles, the method for identifying the embedded end position of deep-sea anchor piles, the verification method for determining the stability of deep-sea anchor piles, or the method for determining the main influencing factors of mooring parameters.

[0025] The twelfth aspect of this specification provides a computer program product comprising a computer program that, when executed by a processor, implements the steps of the above-described method for determining the stability of deep-sea anchor piles, the method for identifying the embedded end position of deep-sea anchor piles, the method for verifying the method for determining the stability of deep-sea anchor piles, or the method for determining the main influencing factors of mooring parameters.

[0026] This invention addresses the core shortcomings of existing deep-sea anchor pile design and stability assessment technologies, such as unsystematic identification of the embedded end, inaccurate division of stress areas, lack of graded stability indicators, insufficient analysis of main control factors, and imperfect experimental verification system. By constructing a systematic system for anchor pile stability assessment, verification, and determination of main control factors of mooring parameters, this invention achieves precision, quantification, and engineering implementation of deep-sea anchor pile design and stability assessment. The specific technical effects include the following six aspects.

[0027] I. To address the lack of a systematic approach to embedded end recognition and provide a scientific and unified recognition solution.

[0028] This invention overcomes the limitations of existing technologies that cannot determine the formation state of embedded ends or distinguish the number of embedded ends. It proposes a method for identifying embedded ends based on pile acceleration data filtering, second-order integral reconstruction of displacement distribution curves, and a "displacement" criterion. This method can systematically identify a single embedded end under static conditions, as well as the average and peak embedded ends under dynamic cyclic loading conditions. It clearly distinguishes the different stress states of 0, 1, or 2 embedded ends, providing a core theoretical basis for anchor pile stability assessment and completely solving the problem of the lack of clear theoretical support in existing anchor pile stability assessment technologies. Simultaneously, cross-validation of the embedded end identification results using synchronously collected earth pressure data further improves the reliability and accuracy of the identification results, avoiding identification errors caused by a single criterion.

[0029] II. Accurately quantify the stress zone of the pile body to improve the accuracy of bearing capacity calculation and displacement prediction.

[0030] This invention uses the identified embedded end location as the core basis to accurately divide the active stress deformation zone (effective stress zone) and passive static zone of the pile body, breaking through the limitation of existing technologies that cannot quantify the stress area. Based on the integral calculation of the soil pressure distribution curve within the effective stress zone, the lateral ultimate bearing capacity is calculated. Compared with the simplified model under the traditional assumption of "completely embedded pile end," this method better reflects the flexible deformation characteristics of deep-sea long-diameter ratio anchor piles, significantly reducing the errors in lateral bearing capacity calculation and displacement prediction. It solves the problem of insufficient design accuracy caused by the ambiguous division of the stress area in existing technologies, making the calculation results more consistent with the actual stress and deformation laws of anchor piles in deep-sea soft soil foundations.

[0031] Third, supplement the graded stability assessment indicators, clarify the safety margin of anchor piles, and optimize the rationality of the design.

[0032] This invention constructs a graded stability assessment system based on the fixed-end state, clearly distinguishing the differences between double-fixed-end (stable state), single-fixed-end (critical state), and no-fixed-end (instability state), and intuitively quantifying the safety margin of anchor piles under different working conditions. In engineering design, the stability level of the anchor pile can be accurately determined according to the fixed-end state of the anchor pile, avoiding the problem of overly conservative design or insufficient safety reserve caused by the lack of graded indicators in existing technologies, and achieving a preliminary balance between the safety and economy of anchor pile design.

[0033] IV. Improve the sensitivity analysis system for key control factors to provide quantitative guidance for parameter optimization.

[0034] This invention employs a controlled variable method to conduct multiple sets of comparative experiments, combined with single-factor local sensitivity analysis, to quantify the influence of various parameters such as pile diameter, pile length, mooring anchor height, mooring angle, and initial tension on the static stability and dynamic service performance of anchor piles. It accurately identifies the key controlling parameters for anchor pile stability, overcoming the limitations of existing technologies that rely on engineering experience for parameter optimization. By plotting parameter-performance influence curves, the invention clarifies the effects of each parameter on the formation conditions of the double-embedded end, the effective stress zone range, and the bearing capacity, providing a quantitative basis for optimizing anchor pile structure and mooring parameters, and truly achieving the optimal balance between economy and safety.

[0035] V. Construct a comprehensive experimental verification system to provide reliable support for theoretical models and engineering practice.

[0036] This invention establishes a standardized experimental verification system covering all static and dynamic working conditions, encompassing multiple parameters and sensors. Experimental parameters cover core design parameters such as pile diameter, pile length, and mooring anchor height. Monitoring methods cover all dimensions of data, including earth pressure, acceleration, tension, and displacement. By strictly controlling experimental boundary conditions, sensor calibration, and soil condition consistency, the repeatability and reliability of experimental data are improved. This experimental system not only provides comprehensive experimental verification and correction support for the anchor pile stability assessment method proposed in this invention, but also directly provides reference experimental data for deep-sea anchor pile engineering design, overcoming the shortcomings of existing experimental systems such as incomplete parameter coverage, single monitoring methods, and inability to guide engineering practice.

[0037] VI. Improve the scientific nature and engineering applicability of deep-sea anchor pile design, and reduce engineering risks and costs.

[0038] In summary, this invention completely solves the problem of blind design in existing deep-sea anchor piles: on the one hand, through precise stability assessment and parameter optimization, it avoids increased construction costs and difficulties caused by overly conservative design; on the other hand, by clearly defining the critical stability state and main control parameters of the anchor pile, it avoids safety hazards caused by underestimating the risks of complex working conditions. Furthermore, the assessment method, verification method, and parameter determination method proposed in this invention can be directly adapted to tensioned mooring systems of various floating marine engineering equipment such as FPSOs and semi-submersible platforms, with a wide range of applications. It can provide comprehensive technical support for the engineering design, construction, and operation and maintenance of anchor piles in deep-sea oil and gas resource development, significantly improving the safety and economy of the entire deep-water oil and gas development project. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0040] Figure 1 This is a simplified model of the lateral force on a mooring anchor pile. Figure 2 Schematic diagrams of dual-embedded end configuration, single-embedded end configuration, and no-embedded end configuration; Figure 3 This is a flowchart illustrating a method for determining the stability of deep-sea anchor piles provided in this specification. Figure 4 This is an alternative flowchart illustrating the method for determining the stability of deep-sea anchor piles provided in this specification. Figure 5 This is a schematic diagram showing the deployment positions of the sensors along the longitudinal axis of the anchor pile; Figure 6 A schematic diagram showing the deployment locations of sensors on the same data acquisition layer; Figure 7 A schematic diagram of the structure of a verification device for a method of determining the stability of deep-sea anchor piles provided in this specification; Figure 8 A flowchart illustrating a verification method for the deep-sea anchor pile stability determination method provided in this specification; Figure 9 A flowchart illustrating a method for determining the main influencing factors of mooring parameters provided in this manual; Figure 10 This is a schematic diagram of a deep-sea anchor pile stability determination device provided in this specification. Figure 11 A schematic diagram of a verification device for the method of determining the stability of deep-sea anchor piles provided in this specification; Figure 12 A schematic diagram of a device for determining the main influencing factors of mooring parameters provided in this manual; Figure 13 This is a structural block diagram of an electronic device provided in this specification. Detailed Implementation

[0041] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this application.

[0042] This invention addresses the core challenges in stability assessment of deep-water mooring anchor piles, and features systematic innovations across four dimensions: theoretical modeling, experimental system design, data acquisition methods, and reliability control. It solves engineering problems such as insufficient accuracy in traditional anchor pile bearing capacity calculation, incomplete coverage of experimental parameters, and poor data repeatability, providing quantifiable theoretical and experimental support for anchor pile design and risk assessment in deep-water oil and gas engineering.

[0043] In terms of theoretical modeling, this invention establishes for the first time a quantitative classification and segmented bearing capacity calculation system for embedded ends. This is specifically reflected in the following two aspects.

[0044] 1. Propose a mathematical definition and a three-state classification standard for embedded ends.

[0045] This invention breaks through the traditional simplistic assumption that the pile end is only considered as a fixed end. For the first time, it defines the embedded end as the equivalent boundary point where the pile body's flexural displacement approaches zero, provides clear mathematical criteria, and quantifies the two core parameters of "embedded end height" and "embedded length".

[0046] Based on the coupling relationship between load location, pile length and soil stiffness, the anchor pile embedment state is divided into three typical forms: no embedment end, single embedment end and double embedment end. The double embedment end is clearly defined as the optimal design goal for the project, and a direct correlation between the number of embedment ends and the overall stability of the anchor pile is established.

[0047] 2. Construct the piecewise deflection differential equation for the load-bearing anchor pile.

[0048] For engineering practice where mooring loads act on the middle of the pile, the elastic beam with uniform cross-section is divided into an upper anchor pile (0≤x≤a) and a lower anchor pile (a≤x≤L) for separate solutions, thus correcting the calculation error of the traditional single-segment model.

[0049] By combining the Euler-Bernoulli beam theory with the Winkler foundation assumption, the transverse deflection control equation considering the coupling of axial force and transverse soil reaction was derived, enabling accurate calculation of the transverse bearing capacity of anchor piles under different embedment states.

[0050] The following section details the innovative aspects of this invention in terms of theoretical modeling.

[0051] In deep-water tensioned mooring systems, anchor piles, as the core load-bearing components connecting floating platforms to the seabed, directly determine the safety and reliability of the entire mooring system under stress. Floating equipment such as Floating Production Storage and Offloading (FPSO) units and semi-submersible platforms continuously endure the combined effects of wind, waves, and currents in the marine environment. The resulting complex dynamic loads are transmitted to the anchor piles through the mooring cables, subjecting the anchor piles to multi-directional and multi-form loads simultaneously.

[0052] Specifically, the total tension exerted by the mooring cable on the anchor pile is an oblique vector, which can be decomposed into two orthogonal components: a horizontal component and a vertical axial component. The horizontal component, perpendicular to the anchor pile's axis, is the primary force causing bending deformation and generating lateral earth pressure, and is also the core control load determining the anchor pile's lateral stability. The vertical axial component, parallel to the anchor pile's axis, mainly causes axial compressive deformation and also has a coupled effect on the anchor pile's lateral bending stiffness, reducing its ability to resist lateral deformation.

[0053] In addition to the external load transmitted by the mooring cable, the anchor pile is also subjected to the reaction forces of the seabed soil, including lateral earth pressure, pile end resistance, and pile side friction. Among these, lateral earth pressure is the main source of the anchor pile's lateral bearing capacity, and its magnitude and distribution directly depend on the lateral displacement of the pile and the mechanical properties of the soil.

[0054] In actual marine environments, the stress and deformation of anchor piles are essentially three-dimensional problems. However, in the engineering design of deep-water mooring systems, mooring cables are typically arranged symmetrically radially. A single anchor pile primarily bears the load within its mooring plane, with out-of-plane load components being negligible and having a negligible impact on its lateral stability. Furthermore, for slender deep-sea anchor piles with length-to-diameter ratios typically between 20 and 30, their out-of-plane bending stiffness is much greater than their in-plane bending stiffness, and their out-of-plane deformation is much smaller than their in-plane deformation. Therefore, the stress and deformation problem of anchor piles can be simplified to a two-dimensional problem. This approach captures the main issues, ensuring the engineering accuracy of the analysis results, while significantly reducing the complexity of theoretical modeling and calculations, making it easier for engineering designers to apply. All subsequent theoretical analyses and experimental studies in this manual are based on the two-dimensional plane assumption, considering only the lateral stress and deformation characteristics of the anchor pile within the mooring plane.

[0055] The wind, wave, and current loads in the marine environment exhibit significant dynamic characteristics, subjecting anchor piles to cyclic loads. However, for the ultimate bearing capacity analysis and stability assessment of anchor piles, the maximum static load under extreme sea conditions is the control condition for engineering design. There are three main reasons for this: 1. The stress and deformation characteristics of anchor piles under static loads are the foundation for dynamic analysis. Only by first clarifying the response laws under static conditions can we further study the dynamic effects caused by cyclic loads, such as soil softening and stiffness degradation; 2. Anchor pile instability and failure typically occur at the peak of extreme loads, at which point the impact of dynamic effects is relatively small, allowing static analysis to conservatively assess the safety margin of the anchor pile; 3. The theoretical solutions obtained from static analysis are concise, facilitating parametric analysis and engineering applications, and can quickly guide the preliminary design and scheme comparison of anchor piles.

[0056] Based on the above analysis, to simplify the analysis, this specification only considers the force characteristics of anchor piles under static lateral loads in a two-dimensional plane.

[0057] For ease of explanation, it is assumed that the total length of the anchor pile (i.e., the total length from the top of the pile to the bottom of the pile) is L. In this specification, the anchor pile position adopts a one-dimensional x-axis coordinate system that points downward along the anchor pile axis from the top of the pile to the bottom of the pile. The position of x=0 represents the top of the anchor pile (i.e., the upper end of the anchor pile, which is usually exposed above the mud surface or flush with the mud surface); the position of x=L represents the end of the anchor pile (or the bottom of the pile) (i.e., the lower end of the anchor pile, the end point that is inserted into the deepest part of the seabed).

[0058] Figure 1 A simplified model of the lateral forces acting on the mooring anchor piles is presented. This model is based on the following fundamental assumptions: (1) Assume that the anchor pile is a uniform and isotropic elastic straight beam with a constant cross section, installed in the seabed soil, and satisfies the Euler-Bernoulli beam assumption; (2) A load T is applied at the middle point a of the anchor pile, and the magnitude of the lateral load is T. x ( Figure 1 (lateral component of the intermediate load T), 0 < a < L, where L is the pile length; (3) The reaction force p(x) provided by the seabed soil to the anchor pile obeys the Winkler foundation assumption, that is, the soil reaction force p(x) at any position is proportional to the displacement y(x) at that position, i.e.: p(x) = ky(x); (4) The anchor pile at x=0 is the pile top, which can be regarded as a free end or partially constrained; at x=L is the pile end, which can be regarded as fully embedded, that is, the displacement is zero. (5) To simplify the modeling, this paper ignores the additional mass and damping caused by seawater buoyancy and flow field, the axial compression deformation of the pile, and the interface slip between the soil and the pile.

[0059] The top of the pile (x=0) is the upper end of the anchor pile. It is not rigidly connected to any large superstructure and only bears tension through the mooring cable. Depending on the strength of the constraint, it is divided into free end (most common) and partially constrained.

[0060] The top of the pile at the "free end" is completely unrestrained and can freely undergo lateral displacement and rotation. The bending moment and shear force at the free end are both zero (except for the lateral load transmitted by the mooring cable), i.e.: M(0) = 0, F τ (0)=T x Where M(0) is the pile top bending moment, F τ (0) represents the shear force at the pile top, T x This represents the lateral load component of the mooring cable.

[0061] The top of a "partially constrained" pile is slightly constrained by the shallow soil or restricted by a cover plate or auxiliary structure at the top, and cannot rotate completely freely, but lateral displacement can still occur.

[0062] The vast majority of deep-sea tensioned mooring piles have a free end at the top, protruding only a few tens of centimeters above the mud surface, used to connect the mooring cable, without any other constraints. Some constraints are only applicable to special cases, such as when the pile top is embedded in shallow hard soil, or when an anti-scour cover is installed on top.

[0063] The pile tip (at x=L) is the lower end of the anchor pile, the deepest point into the seabed, tightly encased by deep soil. Deep-sea anchor piles typically penetrate tens of meters into the seabed, where the stiffness of the deep soil is far greater than that of the shallow soil, resulting in extremely strong constraint on the pile tip. Under normal service conditions, its displacement is extremely small (lateral displacement is usually less than 1 mm), and can be approximated as completely immobile and unable to rotate. That is: y(L)=0 (displacement is 0, no lateral movement can occur).

[0064] Consider a small element dx of the anchor pile at any position x. According to the shear force and bending moment equilibrium equations, the relationship between shear force and bending moment satisfies: —(1) Based on the vertical force balance relationship of the anchor pile, the shear force and lateral load relationship satisfy: —(2) According to the Euler-Bernoulli beam theory, the relationship between bending moment and lateral displacement is as follows: —(3) Combining the above equations, we can obtain the differential equation governing the lateral deflection of the anchor pile on the seabed: —(4) In the above formula, k is the soil reaction coefficient, in kN / m³; y(x) is the lateral displacement, in m; E is the elastic modulus of the pile; I is the moment of inertia of the section; and M(x) represents the bending moment of the infinitesimal segment of the mooring anchor pile, in N. m; N(x) is the axial force of the mooring anchor pile, in N; EI (i.e., E I) represents the bending stiffness of the mooring anchor pile, in N. m²; x is the coordinate of the anchor pile length direction, in meters; p(x) represents the soil reaction force per unit length, in N / m.

[0065] make Then the above formula (4) can be simplified to: —(5), The general solution to formula (5) is: —(6), C1, C2, C3, and C4 are coefficients.

[0066] In deep-water mooring systems, anchor piles bear tension from mooring cables. Their stability depends not only on the structural strength of the pile itself but also significantly on the reaction forces provided by the seabed soil. Under stress, slender piles exhibit a degree of compliance under lateral tension, with response characteristics similar to the deformation behavior of a "flexible beam" constrained by the foundation. When the tension is large or located near the center, the pile will exhibit significant bending deformation.

[0067] To quantify the stress zone and deformation characteristics of anchor piles in soil, this invention introduces the concept of a "fixed end." A fixed end refers to a point where, after the pile reaches a specific location, the soil reaction stiffness significantly increases, and the pile's flexural displacement rapidly decreases to near zero. There is essentially no relative slippage or bending between the pile and the soil, thus it can be considered an equivalent fixed boundary. Mathematically, the displacement at this point satisfies: —(7), Where, x e This indicates the coordinates of the fixed end within the pile body.

[0068] The number of embedded ends of anchor piles under lateral loads is not a fixed value, but rather exhibits three typical forms depending on the load location, the total length of the anchor pile, the seabed soil reaction coefficient, and the magnitude of the lateral load. Different embedded end forms correspond to drastically different stress-deformation characteristics and stability levels of the anchor piles, such as... Figure 2 As shown, it is specifically divided into three states: dual-embedded fixed-end state, single-embedded fixed-end state, and no-embedded fixed-end state. These three states are explained in detail below.

[0069] 1. Dual-embedded fixed-end configuration (target state in engineering design).

[0070] When the mooring load is applied to the middle of the pile, the anchor pile depth meets the requirements, and the seabed soil has sufficient supporting stiffness, the pile deformation on both sides above and below the point of application of the lateral load can be effectively constrained by the soil. At this time, the pile will form static regions with displacement approaching zero above and below the load, exhibiting a double-fixed-end characteristic.

[0071] In the double-embedded-end configuration, the two embedded ends divide the pile body into three regions: the upper ineffective zone (from the pile top to the upper embedded end), the middle effective load-bearing zone (between the upper and lower embedded ends), and the lower ineffective zone (from the lower embedded end to the pile tip). The lateral load on the anchor pile is entirely borne by the soil reaction force in the middle effective load-bearing zone. The pile body is firmly "clamped" by the two embedded ends, resulting in minimal lateral displacement and optimal overall stability—the ideal state pursued in the design of deep-water mooring anchor piles.

[0072] 2. Single-embedded fixed-end morphology (critical stable state).

[0073] When the lateral load increases to a certain value, or when the soil stiffness is insufficient or the load is applied too high, the shallow soil above the load cannot provide sufficient restraint stiffness. The upper section of the pile will undergo bending deformation from the pile top to the load application point, failing to form a near-zero displacement static area. At this point, only the pile deformation below the load can gradually decrease to near zero with increasing depth, forming only a single fixed end below the load.

[0074] In the single-fixed-end state, the effective stress zone of the anchor pile is only the pile segment between the load application point and the lower fixed end, while the entire upper pile body participates in deformation. Compared with the double-fixed-end state, the overall stiffness of the anchor pile is significantly reduced, the pile top displacement is greatly increased, and the safety margin is decreased, which is a critical stability state. The upper limit of the load must be strictly controlled to avoid instability.

[0075] 3. No fixed end morphology (instability state).

[0076] If the lateral load continues to increase and exceeds the maximum restraint capacity that the soil can provide, the entire pile will undergo significant lateral bending deformation. There will be no static area with displacement approaching zero along the pile length direction, exhibiting an overall "flexural drift" state, which can be regarded as an unfixed end.

[0077] Without the anchor end embedded, the interaction between the pile and the soil can no longer effectively limit the lateral displacement of the anchor pile. The anchor pile may be pulled out or broken at any time, resulting in extremely poor stability. This is an unstable state that must be avoided in engineering.

[0078] Based on the analysis of the various forms of the embedded ends, it is evident that the number and distribution of the embedded ends directly determine the stress mode and stability level of the anchor pile. Accurately identifying the number and specific location of the embedded ends under different working conditions is the core foundation for establishing a theoretical model of the lateral bearing capacity of the load-bearing anchor pile and conducting precise stability assessments. It is also a crucial prerequisite for ensuring the safe operation of deep-water mooring systems.

[0079] Based on the above definition of the embedded end, this invention further proposes the concepts of embedded end height and embedded length. The vertical distance from the anchor point to the pile bottom is defined as the embedded end height, while the horizontal distance between the point where the lateral tension is applied and the embedded end is defined as the embedded length. The embedded length not only reflects the stress area of ​​the pile under lateral loads but is also closely related to soil stiffness, pile flexibility, and the location of the load application, making it an important parameter for subsequent bearing capacity analysis and displacement prediction.

[0080] Because the load is applied at the middle of the anchor pile, the shear force at the load point changes abruptly, and the deformation patterns of the upper and lower sections differ. Therefore, the uniform cross-section elastic beam needs to be divided into two independent regions for separate solutions. Specifically: Upper anchor pile: satisfies 0≤x≤a, and the general solution of displacement is denoted as y1(x); The lower anchor pile satisfies a≤x≤L, and the general solution of the displacement is denoted as y2(x).

[0081] The general solution for the displacement of the anchor piles at both ends is shown in the following formula (8): —(8), Where c1, c2, c3, c4, c5, c6, c7, and c8 are coefficients. These eight coefficients can be obtained by combining three types of boundary conditions, leading to the uniquely determined pile displacement distribution functions y1(x) and y2(x). These three types of boundary conditions include (see the description above): 1. Pile top boundary conditions: When the pile top is a free end, M(0) = 0, F τ (0)=T x When the pile top is partially constrained, M(0) = k0·y'(0), F τ (0)=T x ; 2. Continuity condition of load application point: y1(a) = y2(b), y1'(a) = y2'(b), M1(a) = M2(b), F τ2 (a)-F τ1 (a) =T x , of which F τ1 (a) represents the shear force F of the upper anchor pile at the load application point x=a. τ2 (a) represents the shear force of the lower anchor pile at the load application point x=a; 3. Pile end boundary conditions: y2(L)=0, y2'(L)=0.

[0082] After obtaining the uniquely determined pile displacement distribution functions y1(x) and y2(x), based on the quantification criteria of the fixed end, the positions where the displacement approaches zero are searched along the entire length of the pile, thus identifying the coordinates of the fixed end. Specifically, The fixed end located above the load application point (0 < x < a) is denoted as x1, i.e., the upper fixed end; The fixed end located below the load application point (a < x < L) is denoted as x2, which is the lower fixed end.

[0083] Based on the identified embedded end position, the upper embedded length L can be determined. Top and the lower segment embedment length L Bottom They are: L Top =a - x1,L Bottom =x2-a.

[0084] The formula for calculating the total lateral bearing capacity is: —(9) Among them, F L denoted as the total lateral bearing capacity, x1 as the coordinate of the upper fixed end, x2 as the coordinate of the lower fixed end, and p(x) as the soil reaction force at the position x on the anchor pile.

[0085] In existing technologies, the calculation method for total lateral bearing capacity is typically as follows: —(10).

[0086] It should be noted that although the pile end (x=L) is fully embedded, the pile end embedment is not equivalent to the embedded end defined in this invention. Existing anchor pile theory takes the theoretical pile end embedment (x=L) as the actual force-bearing embedded end, and assumes that the entire pile length participates in the force. Specifically, this is reflected in the fact that the integral interval of formula (10) is larger than that of formula (9), which leads to the calculated bearing capacity of the anchor pile being much larger than the actual bearing capacity that the anchor pile can withstand.

[0087] The present invention accurately determined the integration interval based on the following findings: (1) When the mooring load is applied to the pile body (0 < a < L), the pile body will form a region with displacement approaching zero on both sides above and below the load, and these regions are the true fixed ends; (2) Only the pile segment between the two fixed ends will undergo bending deformation and participate in the formation of bearing capacity; (3) The pile segment below the fixed end (including the theoretical pile end x=L) is almost motionless and does not contribute to the bearing capacity.

[0088] This invention provides the first explanation of the physical phenomena of "double embedded ends" and "ineffective zones" in load-bearing anchor piles, and proposes a method to identify the embedded end positions by solving differential equations piecewise, thereby accurately dividing the effective stress zone. By integrating only the soil reaction force in the effective zone, accurate bearing capacity calculation results are obtained. This not only solves the theoretical deviations of existing methods, but also significantly reduces the design and construction costs of deep-sea anchor piles while ensuring engineering safety, and has significant engineering application value.

[0089] Based on the above analysis, this specification provides a method for determining the stability of deep-sea anchor piles, such as... Figure 3 As shown, the method includes the following steps S11 to S13.

[0090] S11: For the engineering case where the mooring load acts on the middle part of the anchor pile, the differential equation for the lateral deflection control of the anchor pile on the seabed is constructed. The anchor pile is divided into upper and lower sections based on the point of application of the mooring load. The differential equation for the lateral deflection control is solved piecewise to obtain the displacement distribution functions of the upper and lower sections of the anchor pile respectively.

[0091] The differential equation governing the lateral deflection of the anchor pile on the seabed can be expressed as Equation (4) above.

[0092] The coordinates of the upper anchor pile satisfy 0≤x≤a, and the coordinates of the lower anchor pile satisfy a≤x≤L.

[0093] The above equation (8) can be solved by combining the above three types of boundary conditions to obtain the pile displacement distribution function y1(x) of the upper anchor pile and the pile displacement distribution function y2(x) of the lower anchor pile.

[0094] S12: Calculate and identify the position of the embedded end based on the pile displacement distribution function of the upper and lower anchor piles; the embedded end is the position point on the pile body where the flexural displacement approaches zero, except for the pile end.

[0095] After obtaining the uniquely determined pile displacement distribution functions y1(x) and y2(x), based on the quantification criteria of the fixed end, the position coordinates of the fixed end can be identified by traversing the entire length of the pile and searching for positions where the displacement approaches zero.

[0096] S13: Determine the stability of the anchor pile based on the number of embedded ends.

[0097] In some embodiments, S13 may include: if the number of embedded ends is two, then determining that the anchor pile has reached the target stable state of the engineering design; if the number of embedded ends is zero, then determining that the anchor pile is in an unstable state.

[0098] In some embodiments, S13 may further include: if the number of embedded ends is one, then the anchor pile is determined to be in a critical stable state; In some embodiments, when two embedded ends are identified, such as Figure 4 As shown, the method further includes S14: calculating the total lateral bearing capacity of the anchor pile based on the integral of the soil reaction force in the region between the two embedded ends of the anchor pile.

[0099] Specifically, the formula for calculating the total lateral bearing capacity is the above formula (9).

[0100] This specification also provides a method for identifying the embedded end position of a deep-sea anchor pile, including S11 and S12 mentioned above. For details, please refer to the description above; further elaboration is unnecessary.

[0101] To verify the aforementioned method for determining the stability of deep-sea anchor piles, this specification provides a verification device for this method. The verification device includes an experimental test model, an installation and environmental simulation system, a data acquisition system, and electronic equipment.

[0102] The experimental test model includes multiple sets of simulated anchor piles with different geometric parameters, as well as a mooring system consisting of anchor chains and polyester cables.

[0103] Multiple sets of simulated anchor piles with different geometric parameters are a series of scaled-down model anchor piles designed using the controlled variable method, differing only in one or more geometric dimensions. These anchor piles can be used to systematically study the influence of structural parameters on anchor pile stability and are the core test objects of the entire experiment.

[0104] Differences in geometric parameters may include pile diameter (i.e., the outer diameter of the anchor pile's cross section), pile length (i.e., the total length of the anchor pile), and anchor hole height (i.e., the vertical height of the mooring cable connection point from the bottom of the pile).

[0105] The simulated anchor pile can be a physical model of the prototype engineering anchor pile made at a 1:60 geometric scale. It must maintain the same aspect ratio, cross-sectional shape, and material properties as the prototype, and satisfy the geometric and mechanical similarity criteria. For example, if the anchor pile prototype is an actual steel pile with a diameter of 2.4m and a length of 63.6m used in deep-sea engineering, then the simulated anchor pile in the experiment can be an aluminum alloy or steel pipe pile with a diameter of 40mm and a length of 1060mm.

[0106] Anchor chains and polyester cables are connected in series via connectors to form a mooring cable, which serves as the force transmission path during mooring. This is the standard design for tensioned mooring systems, rather than cables made of a single material.

[0107] The installation and environmental simulation system includes a soil box for simulating seabed soil, a vertical loading system for simulating anchor insertion and extraction, and a swing motor for applying periodic loads.

[0108] The soil tank is the core device for simulating the deep-sea seabed and the upper water environment. The internal space of the soil tank can hold a sufficient amount of simulated seabed soil, and its size design can fully consider the influence of boundary effects, ensuring that the minimum distance between the anchor pile and the side wall of the soil tank is not less than 6 times the diameter of the anchor pile, so as to eliminate the interference of boundary constraints on the pile-soil interaction.

[0109] To construct a simulated seabed soil mass, simulated saltwater can be added to the soil tank up to 0.3m above the mud surface to simulate a deep-sea saturated soft soil environment. The soil tank can hold a sufficient amount of soil, and through layered filling and consolidation, it can effectively reproduce the mechanical properties and boundary conditions of deep-sea soil, providing a basis for subsequent experiments.

[0110] In some embodiments, the seabed soil used in the experiment can be collected from a nearshore shallow water area of ​​a certain sea area. It is a typical soft clay and sandy soil deposited by tides and marine environments, exhibiting characteristics such as high water content and low strength, and possesses strong representativeness and engineering research value. To ensure the consistency and repeatability of experimental conditions, the soil preparation can adopt a standardized process, the main steps of which are as follows: (1) Sample pretreatment stage: The original sampled soil is manually screened to remove large particles such as pebbles and gravel to obtain homogeneous fine-grained clay and sand. (2) Soil reconstruction: The treated soil is thoroughly mixed with salt water with a density of 1.03 g / cm³ according to the mass ratio. Mechanical stirring is used to ensure that the salt water penetrates evenly into the soil pores, thereby achieving the initial reconstruction of the soil-water structure. (3) Refinement treatment: The mixed clay and sand are passed through an 80-mesh sieve to remove any fine impurities and large particle agglomerates that may remain, so as to improve the consistency of the experiment and the uniformity of the pore distribution. (4) Static curing: The screened refined clay and sand were slowly filled into the soil box to simulate the seabed sedimentation state, and brine with a density of 1.03 g / cm³ was continuously added to keep the water level 0.3 m above the mud surface. Then, the soil was allowed to settle naturally in a static state and cured for 72 hours to ensure that pore water could fully infiltrate and the soil structure was stable. The properties of the soil in the soil box and the soil properties of the landslide soil are shown in Tables 4.5 and 4.6. (5) Maintenance and monitoring: After waiting for a sufficient time, continue to add salt water to the predetermined water level to form a simulated upper water environment and ensure that the model soil is fully saturated throughout the experiment.

[0111] The soil obtained through the above preparation process has good homogeneity and stability, and its mechanical and seepage properties are suitable for simulation studies of tensioned mooring anchor piles in the deep sea surface.

[0112] The vertical loading system is used to achieve precise insertion and installation of simulated anchor piles and non-destructive extraction after the experiment. It is a key piece of equipment to ensure the consistency of the initial experimental conditions. The vertical loading system can adopt an electric servo-driven ball screw transmission method, with a rated load range of 0–100kN and a displacement control accuracy of ±0.1mm.

[0113] In some embodiments, the system is fixed above the soil box by a loading system truss, and the output end of the vertical loading motor is rigidly connected to the top of the anchor pile through a transmission link. Support frame guide rails are provided on both sides of the link to provide linear motion guidance and prevent the link from lateral swaying and twisting during loading.

[0114] Before the experiment, the vertical loading system pressed the anchor pile vertically into the soil to the designed depth at a constant rate, and used closed-loop control to ensure that the verticality of the anchor pile installation was controlled within ±1°. After the experiment, the system reversed its operation to pull out the anchor pile at a uniform speed, avoiding damage to the anchor pile and sensors. In addition, the system can also apply a constant axial load as needed to study the effect of the coupling effect of the vertical component of the mooring cable and the lateral load on the stability of the anchor pile.

[0115] The swing loading motor is the core actuator that simulates the application of lateral loads to anchor piles by a floating platform under the action of waves and flow fields. The maximum output force can reach 0-600N, and it can realize two working modes: static monotonic loading and dynamic cyclic loading.

[0116] In the static ultimate bearing capacity test, the oscillating motor adopts a static monotonic loading mode, which is to apply a monotonically increasing quasi-static load by rotating unidirectionally at an extremely slow rate until the anchor pile becomes unstable and fails. In the dynamic cyclic load test, the oscillating motor adopts a dynamic cyclic loading mode, which is to oscillate periodically according to a preset frequency and amplitude to simulate the "tension-relaxation" cycle of the mooring cable under normal sea conditions.

[0117] The swing motor can be equipped with a high-precision force feedback control system, which can adjust the output load in real time, ensuring the stability and repeatability of the loading amplitude and frequency, and providing a reliable loading method for studying the stress and deformation response of anchor piles under different load conditions.

[0118] In some embodiments, the swing arm can be installed at the end of the loading system truss, with its loading arm and the top fixed pulley at the same horizontal level, so that the loading path of the mooring cable remains stable and avoids additional errors caused by changes in the loading direction.

[0119] The data acquisition system includes: soil pressure sensors and acceleration sensors installed on the simulated anchor piles, tension sensors installed at both ends of the mooring cable, displacement sensors for monitoring anchor pile displacement, and a data acquisition instrument for collecting data from all sensors.

[0120] Earth pressure sensors are used to measure the lateral reaction force of seabed soil on anchor piles at different depths, and are a key measuring element for revealing the pile-soil interaction mechanism. The core functions of earth pressure sensors include: first, verifying the correctness of the Winkler foundation hypothesis by inverting the soil foundation reaction coefficient k through the correspondence between measured earth pressure and pile displacement; second, serving as a cross-validation criterion for identifying the fixed-end location, where the relative displacement between the pile and soil approaches zero, the corresponding lateral earth pressure should also approach zero; and third, calculating the experimentally measured lateral ultimate bearing capacity by integrating the whole-pile earth pressure distribution curve, and comparing and verifying the results with theoretical calculations.

[0121] In some embodiments, a thin-film earth pressure sensor can be used, with a range of 0–500 N, a sensitivity of 0.5%, dimensions of 5 mm × 5 mm × 0.3 mm, a response time of less than 2 ms, and adaptability to underwater experimental environments ranging from -20℃ to 60℃. The sensor is surface-mounted, with five layers along the entire length of the pile, one sensor symmetrically arranged on each of the left and right sides of the pile in each layer, for a total of 10 sensors. The sensors are closely attached to the outer surface of the pile and flush with the pile surface, minimizing interference with the pile-soil contact state.

[0122] Accelerometers are used to measure the lateral vibration acceleration response at different depths of the pile, and are the core component for indirectly obtaining the displacement distribution across the entire pile cross-section. The core function of the accelerometer is to calculate the lateral relative displacement at each measuring point on the pile using a double integration method: the acquired acceleration time history curves are numerically integrated twice, and combined with the boundary condition that the initial velocity and initial displacement are both zero, the displacement time history curves for each measuring point are obtained. The average displacement on both sides at the same depth is taken as the measured displacement at that point, eliminating measurement errors caused by pile torsion.

[0123] In some embodiments, a LIS2HH12 dynamic acceleration sensor can be used, with a range of ±2.0g and an applicable temperature range of -40℃ to 85℃. It features high resolution and low noise, enabling accurate capture of weak vibration signals from the pile. The sensors are symmetrically arranged in the same layer as the earth pressure sensors, divided into five layers along the entire length of the pile, with one sensor on each side of each layer, for a total of ten sensors. These sensors are installed side-by-side with the earth pressure sensors at the same height.

[0124] Tension sensors are used to monitor the axial tension of the mooring cable in real time and are key measuring elements for accurately controlling experimental loads and obtaining the true force on the anchor pile. Two sensors are respectively installed at both ends of the mooring cable: the first is installed at the connection between the oscillating motor and the polyester cable to measure the load tension output by the motor; the second is installed at the connection between the anchor chain and the anchor pile eye to measure the effective load actually acting on the anchor pile.

[0125] Simultaneous placement of tension sensors at both ends eliminates tension loss caused by pulley friction, elastic deformation of the polyester cable, and hinge friction of the anchor chain, accurately obtaining the true stress state of the anchor pile. Its core functions include: first, precisely adjusting the initial tension to the design value before the experiment using feedback from the tension sensors at the anchor pile end, ensuring strict adherence to the controlled variable method; second, monitoring load changes in real time during the experiment to ensure that the load amplitude and frequency output by the oscillating motor meet experimental requirements; third, recording the maximum tension at the moment of anchor pile instability as the experimentally measured ultimate bearing capacity; and fourth, analyzing the mechanical characteristics of the mooring system through the difference in tension at both ends, achieving fault diagnosis and data cross-validation during the experiment.

[0126] In some embodiments, two DYHM-103 cable tension sensors can be configured, with a measurement range of 0–500 kg, overload protection of 150%, hysteresis error of 0.1%FS, output voltage of 0–10V, and response frequency of 10kHz. The two sensors are respectively installed at both ends of the mooring cable: the first is installed at the connection between the swing motor and the polyester cable to measure the loaded tension output by the motor; the second is installed at the connection between the anchor chain and the anchor pile eye to measure the effective load actually acting on the anchor pile.

[0127] Displacement sensors are used to directly measure the absolute lateral displacement of the anchor pile top, serving as the benchmark measurement element for calibrating the acceleration-integrated displacement and determining the anchor pile's instability state. The core functions of the displacement sensor include: first, serving as the absolute benchmark for overall pile displacement measurement, calibrating the relative displacement obtained from the second integration of the acceleration sensor, and eliminating integration drift errors; second, directly recording the pile top displacement under different loads, plotting load-displacement curves, and analyzing the overall stiffness changes of the anchor pile; and third, serving as the basis for judging anchor pile instability, determining that the anchor pile has reached its ultimate bearing capacity when the pile top displacement undergoes a sudden change or exceeds a preset threshold.

[0128] In some embodiments, an MPS-M-800 cable displacement sensor can be used, with a range of 0–800 mm and a measurement error of ±0.1%, featuring high precision and high reliability. One end of the sensor is fixed to the loading system truss, and the other end is rigidly connected to the top of the anchor pile via a steel wire rope, enabling real-time monitoring of lateral displacement changes at the pile top.

[0129] Multiple acquisition layers can be set along the longitudinal axis of the anchor pile (these acquisition layers can be set at equal intervals), and an earth pressure sensor and an acceleration sensor are set in each acquisition layer; on each acquisition layer, at least two earth pressure sensors are symmetrically set along the longitudinal axis of the anchor pile, and at least two acceleration sensors are symmetrically set along the longitudinal axis of the anchor pile.

[0130] like Figure 5As shown, T1 is the anchor eye (i.e., the mooring cable connection point). Five data acquisition layers (HighA, High B, High C, High D, and High E) can be set along the longitudinal axis of the anchor pile. Each acquisition layer is equipped with an earth pressure sensor Px (where x is a positive integer to distinguish different earth pressure sensors) and an acceleration sensor Dx (where x is a positive integer to distinguish different acceleration sensors). For example... Figure 6 As shown, in the High A acquisition layer, earth pressure sensors P1 and P2 are symmetrically arranged along the longitudinal axis of the anchor pile, and acceleration sensors D1 and D2 are symmetrically arranged along the longitudinal axis of the anchor pile.

[0131] The data acquisition unit is the control center of the entire measurement system, responsible for synchronously acquiring the output signals of all sensors and transmitting the data to the computer for storage and processing. Two dedicated data acquisition units can be used to achieve separate acquisition of high-frequency dynamic signals and low-frequency quasi-static signals, ensuring the measurement accuracy of different types of signals.

[0132] For example, the two dedicated data acquisition instruments can be: 1. DT9837 series portable dynamic signal acquisition instrument: specifically designed for acquiring high-frequency dynamic signals output by accelerometers, featuring high resolution, low noise, and wide dynamic range, accurately reproducing the vibration waveform of the pile body and avoiding high-frequency signal distortion; 2. XL2118B18 24-channel data acquisition instrument: used to acquire low-frequency quasi-static signals output by soil pressure sensors, tension sensors, and displacement sensors, supporting three bridge modes: 1 / 4 bridge, 1 / 2 bridge, and full bridge, and adaptable to the output methods of different types of sensors.

[0133] The aforementioned data acquisition system establishes a multi-source integrated full-pile response monitoring system, specifically reflected in the following two aspects: 1. Symmetrical multi-sensor array arrangement: Earth pressure sensors and acceleration sensors are symmetrically arranged on both sides of the anchor pile, with 5 sets on each side and evenly distributed along the entire length of the pile. This allows for simultaneous monitoring of the earth pressure difference and lateral vibration response on both sides of the pile, avoiding errors from single-sided monitoring. A dual-tension sensor series arrangement (oscillating motor end + anchor eye end) is used to monitor tension loss in the loading path in real time, correcting the limitation of traditional single sensors that can only measure output load. 2. Multi-sensor data fusion calibration: Combining the complementary advantages of cable displacement sensors (direct measurement) and acceleration sensors (integral calculation), the accuracy and reliability of lateral displacement monitoring are improved. Equipped with a temperature compensation module and signal amplifier, covering a frequency response range of 5-20kHz, it can simultaneously capture low-frequency earth pressure changes and high-frequency vibration signals, avoiding data loss.

[0134] The electronic equipment is used to verify the method for determining the stability of deep-sea anchor piles based on the collected data from various sensors, and / or to analyze the main influencing factors of mooring parameters and determine the optimal design range of the main influencing factors.

[0135] Figure 7 This is a schematic diagram of the structure of a verification device for a method to determine the stability of deep-sea anchor piles provided in this specification. In the diagram, ① is a computer; ② is a data acquisition instrument; ③ is a support frame guide rail; ④ is a support frame; ⑤ is a loading system truss; ⑥ is a vertical loading motor; ⑦ is a load transmission and displacement sensor fixing link; ⑧ is a displacement sensor; ⑨ is a simulated anchor pile; and ⑩ is an acceleration sensor. Earth pressure sensor; For the tension sensor at anchor end T1; For mooring anchor chains; For mooring polyester cables; To simulate seawater; To simulate seabed soil; For earthen boxes; The top fixed pulley; It is a traction angle adjustment device; To load the system load cabinet; For connecting wires; For the T2 tension sensor at the swing motor end; For swing motor load cabinet; A swing-loaded motor.

[0136] The aforementioned verification equipment can be designed on a scaled-down basis using similarity theory to establish the geometric and mechanical relationships between the prototype engineering and the model experiment. Due to the enormous size of deep-sea engineering equipment and the complexity of environmental loads, conducting full-scale physical experiments directly is not feasible in engineering practice; therefore, representative experiments must be achieved through scaled-down models. This experiment primarily follows geometric and mechanical similarity principles.

[0137] Geometric similarity refers to scaling down the model's length, diameter, burial depth, and other geometric features according to a uniform geometric scale factor to maintain consistency with the prototype's shape and structural proportions. For anchor piles, a 1:60 scaling ratio is used to ensure that their diameter, length, and height protruding above the mud surface accurately reflect the geometric features of the prototype. —(11) Among them, S L For geometric similarity ratio, L p L is the characteristic length of the prototype project. m This represents the corresponding feature length of the experimental model.

[0138] Mechanical similarity refers to considering the interaction forces between the soil and the structure while ensuring geometric similarity. Through mechanical similarity criteria, the proportional relationships between the horizontal and vertical forces acting on the piles in the model are kept consistent with the prototype. For example, a 1:360 mechanical scaling ratio can be used, combined with appropriate loading devices, to achieve an equivalent reproduction of the prototype's load effects. This experiment is a two-dimensional problem, where the force is proportional to the square of the geometric dimension, i.e.: —(12) Among them, F P For forces in prototype engineering, F m For the stress in the experimental model, S L 2 L is the mechanical similarity ratio (i.e., a force scaling factor). p L is the characteristic length of the prototype project. m This represents the corresponding feature length of the experimental model.

[0139] This specification also provides a verification method for the deep-sea anchor pile stability determination method, which can be used to verify the aforementioned deep-sea anchor pile stability determination method using the aforementioned deep-sea anchor pile stability determination equipment. For example... Figure 8 As shown, the verification method includes the following steps S21 to S25.

[0140] S21: After installing the sensors and completing the calibration according to the preset experimental plan, control the vertical pressing of the anchor pile into the simulated seabed soil to the design depth, and adjust the initial tension to the design value after connecting the mooring system.

[0141] Before the experiment, three core tasks need to be completed: sensor installation and calibration, precise installation of anchor piles, and debugging of the mooring system, to ensure that all initial conditions strictly meet the requirements of the experimental plan.

[0142] Regarding sensor installation and calibration, for example, following a layered symmetrical arrangement scheme, soil pressure sensors and acceleration sensors are installed on the left and right sides of the simulated anchor pile, respectively, with 5 sets of sensors evenly distributed on each side, and the lowest set of sensors being 10mm from the bottom of the pile. All sensors undergo zero-point calibration and sensitivity testing before installation. After installation, they are encased in waterproof material and secured with thin film tape to prevent water immersion, friction, or vibration from damaging the sensors or causing signal errors.

[0143] For precise anchor installation, the anchor installation position is calculated based on the preset mooring angle, and the anchor is vertically pressed into the simulated seabed soil to the design depth using a vertical loading system. During installation, the verticality of the anchor is monitored in real time using a high-precision inclinometer to ensure that the angle between the anchor and the mud surface does not exceed the preset angle range (e.g., ±1°). Simultaneously, the minimum distance between the anchor and the sidewall of the soil box is ensured to be no less than 6 times the anchor diameter, eliminating the interference of boundary effects on the anchor response.

[0144] Regarding the mooring system connection and initial tension adjustment, the mooring system consists of a steel anchor chain and a polyester cable connected in series. In the experiment, the anchor chain was controlled to maintain a predetermined length (e.g., 200mm-300mm) protruding above the mud surface under tension. The polyester cable was guided to the loading arm of the swing motor via a fixed pulley. The initial tension was adjusted by changing the length of the polyester cable, and monitored in real time by a tension sensor at the anchor pile end to ensure that the deviation between the initial tension and the design value did not exceed the preset tension range (e.g., ±0.1N).

[0145] S22: Start the data acquisition system, control the swing motor to apply the preset load, and continuously and synchronously collect data on soil pressure, acceleration, tension at both ends of the mooring cable, and displacement of the top of the anchor pile at each measuring point on the pile body.

[0146] Verification method S22 includes two working conditions: static ultimate bearing capacity test (i.e., static test) and dynamic cyclic load test (i.e., dynamic test), to verify the accuracy of the evaluation method under static and dynamic conditions respectively.

[0147] The steps of the static ultimate bearing capacity test include the following steps S221 to S223.

[0148] S221: Control the swing motor to rotate unidirectionally at a slow rate less than the predetermined rate, apply a monotonically increasing quasi-static load, and collect complete pile earth pressure and acceleration data once after each load level stabilizes.

[0149] S222: Identify the static fixed end positions under different loads and calculate the static ultimate bearing capacity.

[0150] S223: Analyze the influence of various parameters on the static embedded end position, effective stress zone range, and static ultimate bearing capacity of the anchor pile.

[0151] For example, a static experiment could be conducted by controlling a swing motor to rotate unidirectionally at an extremely slow rate of 0.1° / s, applying a monotonically increasing quasi-static load. Each load level is held for 30 seconds after stabilization, allowing the pile deformation and earth pressure distribution to fully stabilize. Then, a complete set of data on pile earth pressure, acceleration, mooring cable tension, and pile top displacement is collected. The experiment continues until the anchor pile fails, recording the maximum tension at the moment of instability and the corresponding pile response data.

[0152] The steps of the dynamic cyclic loading test include the following steps S224 to S226.

[0153] S224: Control the swing motor to swing periodically back and forth according to the preset frequency and amplitude to simulate periodic wave load. After each preset number of cycles, the loading is paused and steady-state pile response data is collected once.

[0154] S225: Identify the average and peak fixed end positions under different cycle numbers, and calculate the dynamic ultimate bearing capacity and the remaining ultimate bearing capacity.

[0155] S226: Analyze the influence of various parameters on the cumulative deformation characteristics, stiffness degradation law and fixed end evolution rate of the anchor pile, and evaluate the service performance of the anchor pile throughout its entire life cycle.

[0156] For example, a dynamic experiment could involve controlling a swing motor to periodically oscillate at a preset frequency (0.1Hz) and amplitude to simulate periodic wave loads under normal sea conditions. The data acquisition system uses a sampling frequency of 1 second per cycle to continuously and synchronously acquire the output signals of all sensors, with a maximum data capacity of no less than 10,000 sets, meeting the continuous monitoring requirements for long-cycle loading. Loading is paused after every 1000 cycles, and steady-state pile response data is collected once to analyze the impact of the number of cycles on the anchor pile performance.

[0157] S23: Perform quadratic integration and filtering on the collected pile acceleration time history data to calculate the lateral displacement of each measuring point; automatically identify the fixed end position in the static experiment based on the displacement criterion, or identify the evolution law of the average fixed end and the peak fixed end in the dynamic experiment respectively; cross-validate the fixed end identification results using the synchronously collected earth pressure data.

[0158] The collected pile acceleration time history data can be processed by Butterworth low-pass filtering to eliminate high-frequency noise interference; then, a second integral is performed to calculate the lateral displacement of each measuring point, and baseline correction technology is used to eliminate integral drift error during the integration process.

[0159] The cubic spline interpolation method was used to interpolate the discrete displacement data of each measuring point to reconstruct the continuous displacement distribution curve of the entire pile length.

[0160] Regarding the automatic identification of the fixed end, in the static experiment, the load increases monotonically and slowly, and the pile deformation and soil pressure distribution are stable and unchanged. Therefore, the fixed end is unique and fixed, and only needs to be calculated once. However, in the dynamic experiment, the load changes periodically (tension-relaxation-tension-relaxation...), which leads to: (1) the pile deformation fluctuates synchronously with the load; (2) the instantaneous fixed end position also changes synchronously with the load; (3) there is no fixed "dynamic fixed end".

[0161] If the static method is applied directly and the instantaneous embedded end at a certain moment is arbitrarily taken as the result, it will lead to: (1) the result is completely random and has no statistical significance; (2) it cannot reflect the long-term stable state of the anchor pile; (3) it cannot evaluate the instantaneous bearing capacity under extreme loads.

[0162] Therefore, the identification of the embedded end under dynamic operating conditions must adopt the process of "intercepting the stable cycle → calculating the instantaneous embedded end time by time → statistically obtaining the average / peak embedded end".

[0163] For example, for static experiments, the static embedded end position can be automatically identified based on the dual criterion of "displacement ≤ 0.1 mm"; for dynamic experiments, acceleration data of 3-5 stable cycles can be extracted, the instantaneous embedded end position can be calculated moment by moment, the average value of all instantaneous embedded ends in one cycle can be obtained as the average embedded end, and the instantaneous embedded end at the moment of maximum load can be obtained as the peak embedded end, and then its evolution law with the number of cycles can be analyzed.

[0164] For cross-validation, the identification results of the fixed end are cross-validated using synchronously acquired earth pressure data. According to the pile-soil interaction theory, the relative displacement between the pile and soil at the fixed end approaches zero, and the corresponding lateral earth pressure should also approach zero. If the measured earth pressure at the identified fixed end location is less than or equal to a small preset value (e.g., 0.5 N), the identification result is considered reliable.

[0165] S24: Determine the effective stress zone of the pile body based on the identified fixed end position, and obtain the theoretically calculated lateral ultimate bearing capacity by integrating the earth pressure distribution curve within the effective stress zone; introduce the soil cyclic softening correction coefficient under dynamic working conditions to calculate the dynamic ultimate bearing capacity and the remaining ultimate bearing capacity.

[0166] When calculating the lateral bearing capacity of anchor piles, the effective stress zone is first determined. Specifically, the pile segment above the embedded end is defined as the effective stress zone, where the soil can provide effective lateral restraint for the anchor pile.

[0167] For static experiments, the earth pressure distribution curve within the effective stress zone can be integrated to obtain the theoretically calculated static lateral ultimate bearing capacity.

[0168] For dynamic experiments, a soil cyclic softening correction factor is introduced to correct the foundation reaction coefficient. The correction factor is determined based on the soil strength test results under different cycles. Based on the corrected foundation reaction coefficient, the dynamic ultimate bearing capacity and residual ultimate bearing capacity are calculated.

[0169] S25: Compare and analyze the theoretical calculation results of the fixed end position and lateral bearing capacity with the experimental measurement results, calculate the relative error, and thus verify the accuracy of the method for determining the stability of deep-sea anchor piles.

[0170] The theoretical calculation results are derived from the above-mentioned method for determining the stability of deep-sea anchor piles by filtering, quadratic integration, curve interpolation, dual criteria identification of the embedded end, and earth pressure data of the pile body acceleration and earth pressure, and by calculating the earth pressure integral.

[0171] The experimentally measured values ​​are obtained directly from displacement sensors and mooring cable tension sensors, without being derived through the above evaluation methods, and are the true fixed end positions and critical bearing capacities of anchor piles for instability.

[0172] Verification experiments show that the fixed-end position error calculated using the above-mentioned method for determining the stability of deep-sea anchor piles is less than 5%, and the lateral bearing capacity error is less than 8%, which is significantly better than existing methods. Existing methods, because they do not consider the ineffective constraints of the soil below the fixed end, generally overestimate the calculated results by 20%-30% (this is because existing methods use the full-pile-length integration method to calculate the lateral bearing capacity). Therefore, the above-mentioned method for determining the stability of deep-sea anchor piles can more accurately reflect the true bearing mechanism of the anchor pile.

[0173] By changing at least one of the following parameters—pile diameter, pile length, anchor hole height, mooring angle, and initial tension—a new pre-designed experimental scheme was formed. Steps S21-S25 were repeated to verify the universal applicability of the deep-sea anchor pile stability determination method under different parameter conditions. The verification results show that the above-mentioned deep-sea anchor pile stability determination method has good accuracy under all parameter conditions and can be applied to the stability assessment of deep-water mooring anchor piles under different engineering conditions.

[0174] The verification method for determining the stability of deep-sea anchor piles described in S21 to S25 above has the following technical effects: 1. By comparing the theoretical calculation results of the fixed end and bearing capacity obtained by the evaluation method with the experimental measurement results directly measured by the sensor and calculating the relative error, the calculation accuracy and precision of this evaluation method can be quantitatively evaluated, avoiding qualitative subjective judgment, and making the verification results quantifiable and reproducible. 2. By using the controlled variable method to successively change key parameters such as pile diameter, pile length, anchor hole height, mooring angle, and initial tension, and repeating the entire experimental and verification process, the general applicability and robustness of the stability assessment method under different combinations of structural and mooring parameters can be systematically verified, proving that the method is not limited to a single working condition and has a wide range of applications in engineering. 3. The entire verification method has a closed-loop process and standardized procedures. It forms a complete system from experimental setup, data acquisition, signal processing, fixed end identification, bearing capacity calculation to error comparison and multi-condition generalization verification. Experimental interference is controllable, and boundary effects and installation deviations are strictly constrained, ensuring that the verification process is repeatable and the verification conclusions are scientific and credible. This provides a solid experimental basis for the engineering promotion and application of methods for determining the stability of deep-sea anchor piles.

[0175] This specification also provides a method for determining the main influencing factors of mooring parameters, which can be used to provide guiding data for the engineering design of deep-water mooring anchor piles based on the aforementioned deep-sea anchor pile stability determination equipment. For example... Figure 9 As shown, the verification method includes the following steps S31 to S35.

[0176] S31: Using the controlled variable method, multiple comparative experiments were conducted to control the influence of at least one of the following on the stability of the anchor pile: pile diameter, pile length, mooring anchor height, mooring angle, and initial tension. Data on pile earth pressure, acceleration, mooring cable tension, and displacement were collected for each group of experiments.

[0177] The mooring angle, derived from the arrangement of anchor piles and the platform's geometry, is the angle between the line connecting the anchor hole of the anchor pile and the platform's mooring guide wheel and the horizontal line. It is a key parameter in static design and differs from the anchor chain incident angle. The anchor chain incident angle is the instantaneous angle between the anchor chain and the mudline under the coupled effects of waves, wind, and currents, reflecting the dynamic response characteristics of the mooring system under sea conditions.

[0178] Multiple sets of comparative experiments were conducted using the controlled variable method. Specifically, pile diameter, pile length, mooring anchor height, mooring angle, and initial mooring tension were each used as a single variable factor, while the remaining experimental environment, soil conditions, installation accuracy, and sensor layout were kept completely consistent. Multiple sets of parameters were set sequentially to form multiple experimental groups. Each experimental group was simultaneously equipped with static loading experiments and dynamic cyclic loading experiments. Both the stability performance of the anchor pile under monotonic quasi-static load and the long-period dynamic cyclic load test simulating wave action were carried out.

[0179] For example, to study the effects of diameter and length on the stability of anchor piles, two groups of anchor piles can be selected for comparative experiments. The first group of experiments uses pile diameter as the main variable, selecting anchor piles numbered 1#, 2#, 3#, 4#, and 5#. The pile depth is maintained at 1000mm, the wall thickness at 1.5mm, the mooring anchor is positioned 677mm above the pile bottom, the mooring angle is 30°, and an initial tension of 15N is applied. The second group of experiments uses pile length as the variable, selecting anchor piles numbered 1#, 6#, 7#, 8#, and 9#. The pile diameter is controlled at 40mm, the wall thickness at 1.5mm, the mooring anchor height is maintained at 677mm from the pile bottom, the mooring angle is 30°, and the initial tension is also set at 15N.

[0180] For example, to study the effect of mooring anchor hole height on anchor pile stability, anchor piles #1, #10, #11, #12, and #13 can be selected as research objects. The experimental conditions are uniformly set as follows: anchor pile diameter 40mm, mud penetration depth 1000mm, pile wall thickness 1.5mm, mooring angle 30°, and initial tension 15N. Based on these conditions, the mooring anchor hole heights, measured from the bottom of the anchor piles, are set to 510mm, 590mm, 677mm, 770mm, and 1020mm, respectively.

[0181] Table 1 below shows the relevant parameters of the verification experiment on the influence of diameter, length, and anchor hole height on the stability of anchor piles.

[0182] Table 1

[0183] For example, to study the effect of mooring angle on anchor stability, anchor pile #1 can be selected as the experimental object. The experimental conditions are set as follows: anchor pile diameter 40mm, mud penetration depth 1000mm, anchor pile wall thickness 1.5mm, mooring eye height 677mm, and applied initial tension 15N. The experiment considers five mooring angles: 20°, 30°, 40°, 50°, and 60°.

[0184] For example, to study the effect of initial tension of the mooring cable on the stability of the anchor pile, anchor pile #1 can be selected as the research object. The experimental conditions are set as follows: anchor pile diameter 40mm, mud penetration depth 1000mm, pile wall thickness 1.5mm; mooring anchor height 677mm, mooring angle 30°. Based on this, five different initial tension levels of the mooring cable are set: 10N, 12.5N, 15N, 17.5N, and 20N.

[0185] Multiple sets of comparative experiments were conducted, setting multiple gradient levels for each parameter under study to form multiple parallel control experiments, ensuring the uniqueness of variables and comparability of conditions. These comparative experiments are inclusive of the static and dynamic experiments; each set of comparative experiments simultaneously includes static and dynamic condition tests, acquiring static stability response and dynamic service response data for the anchor piles. During the experiments, uniformly collected full-dimensional measured data on pile earth pressure, acceleration, mooring cable tension, and anchor pile displacement for each set, laying a standardized data foundation for subsequent quantitative analysis.

[0186] S32: By processing multiple sets of controlled variable experimental data through verification equipment, establish a quantitative relationship between parameters such as pile diameter, pile length, mooring anchor height, mooring angle, initial tension and anchor end position, lateral bearing capacity, cumulative deformation and stiffness degradation rate.

[0187] The deep-sea anchor stability determination equipment performs unified preprocessing, signal analysis, and algorithm calculation on the measured data of each group of controlled variable experiments. Based on the aforementioned fixed end identification, bearing capacity solution, and dynamic deformation evolution analysis process, it batch calculates the core performance indicators such as the anchor fixed end position, lateral ultimate bearing capacity, cumulative deformation under cyclic load, and stiffness degradation rate corresponding to each group of experiments.

[0188] Based on this, a quantitative numerical relationship is established between the input design parameters such as pile diameter, pile length, mooring anchor height, mooring angle, and initial tension, and various static and dynamic performance indicators of the anchor pile, so as to realize the digital correlation and characterization between the design parameters and the stability performance of the anchor pile.

[0189] S33: Using sensitivity analysis, the influence of each parameter on the static stability and dynamic service performance of the anchor pile is quantified, and the key control parameters for controlling the stability of the anchor pile are identified.

[0190] A single-factor local sensitivity analysis method was adopted. The fixed end position and lateral bearing capacity calculated by each group of experiments were used as static stability evaluation indicators, and the cumulative deformation, stiffness degradation rate and fixed end evolution rate were used as dynamic service performance evaluation indicators. Based on the parameters and corresponding performance of the benchmark experimental group, the relative change rate of each design parameter and the relative change rate of the corresponding anchor pile performance index were calculated respectively. The absolute value of the ratio of the two was used as the sensitivity coefficient. The magnitude of the sensitivity coefficient was used to quantify the influence of each parameter on the static stability and dynamic service performance of the anchor pile.

[0191] The key control parameters are identified as follows: they are sorted according to the magnitude of their sensitivity coefficients. Parameters with large sensitivity coefficients, where even small fluctuations can cause significant changes in the anchor pile's bearing capacity, embedded end position, deformation, and stiffness, are identified as key control parameters. Parameters with medium sensitivity coefficients that have a certain impact on performance are classified as secondary influencing parameters. Parameters with small sensitivity coefficients that have a negligible impact on the stability of the anchor pile are classified as non-sensitive parameters. This method accurately distinguishes between core parameters that require key control in the design and secondary parameters that can be flexibly selected.

[0192] S34: Plot the influence curves of each parameter on the performance of the anchor pile, and analyze the effect of parameter changes on the formation conditions of double embedded ends, the effective stress zone range and bearing capacity.

[0193] The location of the embedded end can be identified using the aforementioned method for identifying the location of the embedded end of deep-sea anchor piles.

[0194] By combining the identification results of static single embedded end, dynamic average embedded end, and peak embedded end, we can start from the characteristics such as curve change trend, slope magnitude, and abrupt change inflection point to analyze the intrinsic laws of the effect of parameter increase or decrease on the conditions for the generation and stable formation of double embedded ends, the length and distribution range of the effective stress zone of the pile body, the ultimate bearing capacity of the anchor pile, the long-term deformation development and stiffness attenuation rate, and clarify the intrinsic mechanism of the influence of each design parameter on pile-soil interaction and anchor pile stability.

[0195] S35: Based on the influence of parameters, determine the optimal design range of anchor pile structure and mooring parameters under different engineering conditions to guide the engineering design of deep-water mooring anchor piles.

[0196] By combining the sensitivity levels of each parameter and the parameter-performance variation curve, and matching the actual engineering conditions such as geological strength, sea state and wave level, and service life of the project in different sea areas, the bearing safety, deformation control and economic rationality of the anchor pile are comprehensively considered. Under the constraints of meeting the safety reserve of the specifications, the stability and controllability of the embedded end, and the cumulative deformation and stiffness degradation not exceeding the limit, the reasonable value range of each structural parameter and mooring parameter is defined to form the optimal design range that is suitable for different engineering conditions.

[0197] This optimal design range can be directly used for the design, parameter comparison and optimization of deep-water mooring anchor pile schemes, avoiding the blindness of traditional experience-based design, and providing quantitative and reliable design basis and technical guidance for practical engineering applications.

[0198] The experimental verification scheme (including verification equipment and methods) for determining the stability of deep-sea anchor piles constructs a multi-dimensional coupled systematic experimental framework, specifically reflected in the following three aspects: 1. Two-stage progressive experimental architecture: The first stage focuses on the main control effects of the anchor pile's own structure and mooring parameters, while the second stage extends to the coupling effect of external landslide disturbances, realizing full coverage of the stability evolution mechanism from "single factor" to "complex disaster", making up for the shortcomings of traditional experiments that only consider static design parameters; 2. Orthogonal comparative experimental design of all-dimensional main control factors: The system selects five core design variables: pile diameter, pile length, anchor hole height, mooring angle, and initial tension. Five gradient levels are set for each variable. A comparative experiment is conducted using the controlled variable method, which can quantitatively identify the influence weight of each parameter on the lateral displacement of the anchor pile, soil pressure distribution, and ultimate bearing capacity. The system clearly distinguishes between the concepts of "mooring angle (static design parameter)" and "anchor chain incident angle (dynamic response parameter)," resolving the design deviation problem caused by confusion between these two types of parameters in engineering. 3. Precise scaled design adapted for deep-sea soft soil: Addressing the two-dimensional pile-soil interaction problem, a matching scheme of geometric and mechanical scaling ratios is adopted. Following the similarity criterion that "force is proportional to the square of the geometric dimension," equivalent reproduction of prototype loads and soil reactions is achieved. Real soft clay from the target sea area is used as the experimental soil. A standardized preparation process recreates the high water content and low strength characteristics of deep-sea saturated soft soil, resolving the disconnect between simulated soil and actual engineering conditions.

[0199] To ensure the accuracy, repeatability, and representativeness of the data obtained during the anchor pile stability verification experiment, strict control must be exercised over multiple aspects, including the experimental environment, sensor configuration, soil treatment, and data acquisition system. Therefore, the following control measures were formulated and strictly implemented to improve the accuracy and reliability of the experiment. The specific operations are as follows: (1) All displacement sensors, earth pressure sensors, accelerometers, and tension sensors shall undergo zero-point calibration and sensitivity testing before installation. Sensors exhibiting drift or abnormal response shall be replaced immediately. (2) All sensors were encased in waterproof material and fixed with thin film tape during the experiment to prevent damage or signal error caused by water immersion, friction or vibration during pile insertion and landslide scouring. (3) The installation position of each anchor pile is arranged according to the calculated mooring angle to ensure that the anchor pile is perpendicular to the mud surface and the error angle is controlled within ±1°. The installation depth and direction are strictly in accordance with the design parameters; (4) In order to eliminate the interference of boundary effects on the anchor pile response, the minimum distance between all piles and the model trench wall is set to more than 6 times the anchor pile diameter to ensure that the soil box boundary has no effect. (5) In the landslide experiment, the positions of the mud storage tank and the guide trough are calibrated so that their centers are aligned with the center of the anchor pile axis to ensure that the sliding soil impacts the anchor pile evenly and improve the consistency of the experiment. (6) Before and after the experiment, check the anchor chain and polyester cable for breakage, wear, or elongation, paying particular attention to whether the permanent deformation exceeds 3% of the original length. If any issues are found, repeat the experiment. (7) After each round of experiments, the experimental soil needs to be filled to restore homogeneity, and then left to stand for at least 72 hours to ensure the stability of the soil structure; (8) The moisture content, density, void ratio and other indicators of the soil were tested before and after each round of experiments to ensure that they were basically consistent with the previous round of experiments; (9) Since the performance of the sensor may fluctuate with the ambient temperature, the data acquisition system is equipped with a temperature compensation module to automatically correct the influence of temperature on the readings and improve data stability.

[0200] This specification provides a device for determining the stability of deep-sea anchor piles, which can be used to implement the aforementioned method for determining the stability of deep-sea anchor piles. For example... Figure 10 As shown, the device includes a construction unit 11, an identification unit 12, and a determination unit 13.

[0201] The construction unit 11 is used to construct the lateral deflection control differential equation of the anchor pile on the seabed for the engineering condition where the mooring load acts on the middle part of the anchor pile. The anchor pile is divided into upper anchor pile and lower anchor pile based on the point of application of the mooring load. The lateral deflection control differential equation is solved segment by segment to obtain the pile displacement distribution function of the upper anchor pile and the lower anchor pile respectively.

[0202] The identification unit 12 is used to calculate and identify the position of the embedded end based on the pile displacement distribution function of the upper and lower anchor piles; the embedded end is the position point on the pile body where the flexural displacement approaches zero, except for the pile end.

[0203] The determining unit 13 is used to determine the stability of the anchor pile based on the number of embedded ends.

[0204] This specification provides a device for identifying the embedded end position of a deep-sea anchor pile, which can be used to implement the aforementioned method for identifying the embedded end position of a deep-sea anchor pile. The device includes a construction unit and an identification unit.

[0205] The construction unit is used to construct the lateral deflection control differential equation of the anchor pile on the seabed for the engineering condition of mooring load acting on the middle part of the anchor pile. Based on the point of application of the mooring load, the anchor pile is divided into upper anchor pile and lower anchor pile. The lateral deflection control differential equation is solved segment by segment to obtain the pile displacement distribution function of the upper anchor pile and the lower anchor pile respectively.

[0206] The identification unit is used to calculate and identify the position of the embedded end based on the pile displacement distribution function of the upper and lower anchor piles; the embedded end is the position point on the pile body where the flexural displacement approaches zero, except for the pile end.

[0207] This specification provides a verification device for a method of determining the stability of deep-sea anchor piles, which can be used to perform the aforementioned verification device for determining the stability of deep-sea anchor piles. For example... Figure 11 As shown, the device includes a first control unit 21, a second control unit 22, a first data processing unit 23, a second data processing unit 24, a comparison unit 25, and a scheme update unit 26.

[0208] The first control unit 21 is used to control the vertical pressing of the anchor pile into the simulated seabed soil to the design depth after the sensor is installed and calibrated according to the preset experimental plan, and to adjust the initial tension to the design value after connecting the mooring system.

[0209] The second control unit 22 is used to start the data acquisition system, control the swing motor to apply a preset load, and continuously and synchronously acquire data on soil pressure, acceleration, tension at both ends of the mooring cable, and displacement at the top of the anchor pile at each measuring point on the pile body.

[0210] The first data processing unit 23 is used to perform secondary integration and filtering on the collected pile acceleration time history data, calculate the lateral displacement of each measuring point; automatically identify the fixed end position in the static experiment based on the displacement criterion, or identify the evolution law of the average fixed end and the peak fixed end in the dynamic experiment respectively; and cross-validate the fixed end identification results using the synchronously collected earth pressure data.

[0211] The second data processing unit 24 is used to determine the effective stress zone of the pile body based on the identified fixed end position, and to obtain the theoretically calculated lateral ultimate bearing capacity by integrating the earth pressure distribution curve in the effective stress zone; under dynamic working conditions, a soil cyclic softening correction coefficient is introduced to calculate the dynamic ultimate bearing capacity and the remaining ultimate bearing capacity.

[0212] The comparison unit 25 is used to compare and analyze the theoretical calculation results of the fixed end position and the lateral bearing capacity with the experimental measurement results, calculate the relative error, and thus verify the accuracy of the method for determining the stability of deep-sea anchor piles.

[0213] The scheme update unit 26 is used to replace at least one of different pile diameter, pile length, anchor hole height, mooring angle and initial tension to form a new preset experimental scheme, so that the first control unit, the second control unit, the first data processing unit, the second data processing unit and the comparison unit can repeatedly execute it to verify the universal applicability of the deep-sea anchor pile stability determination method under different parameter conditions.

[0214] This specification provides a device for determining the main influencing factors of mooring parameters, which can be used to implement the above-mentioned method for determining the main influencing factors of mooring parameters. For example... Figure 12 As shown, the device includes a third control unit 31, a third data processing unit 32, a fourth data processing unit 33, an analysis unit 34, and a second determination unit 35.

[0215] The third control unit 31 is used to conduct multiple comparative experiments on the influence of at least one of the following on the stability of the anchor pile using the controlled variable method: pile diameter, pile length, mooring anchor height, mooring angle, and initial tension. Data on pile earth pressure, acceleration, mooring cable tension, and displacement are collected for each group of experiments.

[0216] The third data processing unit 32 is used to process multiple sets of experimental data of controlled variables through the above-mentioned verification equipment, and to establish a quantitative relationship between parameters such as pile diameter, pile length, mooring anchor height, mooring angle, and initial tension and the anchor pile embedment end position, lateral bearing capacity, cumulative deformation and stiffness degradation rate; wherein, the embedment end position identification method of deep-sea anchor pile described above is used to identify the embedment end position.

[0217] The fourth data processing unit 33 is used to employ sensitivity analysis to quantify the influence of each parameter on the static stability and dynamic service performance of the anchor pile, and to identify the key control parameters for controlling the stability of the anchor pile.

[0218] Analysis unit 34 is used to plot the influence curves of each parameter on the performance of the anchor pile, and to analyze the effect of parameter changes on the formation conditions of double embedded fixed ends, the effective stress zone range and bearing capacity.

[0219] The second determining unit 35 is used to determine the optimal design range of anchor pile structure and mooring parameters under different engineering conditions based on the parameter influence law, so as to guide the engineering design of deep-water mooring anchor piles.

[0220] The descriptions and functions of the above-mentioned devices can be understood by referring to the corresponding methods section, and will not be repeated here.

[0221] This invention also provides an electronic device, such as... Figure 13 As shown, the electronic device may include a processor 1301 and a memory 1302, wherein the processor 1301 and the memory 1302 may be connected via a bus or other means. Figure 13 Taking the example of a connection between China and Israel via a bus.

[0222] Processor 1301 may be a central processing unit (CPU). Processor 1301 may also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or combinations thereof.

[0223] The memory 1302, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs, non-transitory computer-executable programs, and modules, such as the program instructions / modules corresponding to the deep-sea anchor stability determination method, the deep-sea anchor embedment end position identification method, the deep-sea anchor stability determination method verification method, or the mooring parameter main control influencing factor determination method in the embodiments of the present invention (e.g., Figure 10 The shown components are the construction unit 13, the identification unit 20, and the determination unit 30. The processor 1301 executes various functional applications and data processing by running non-transient software programs, instructions, and modules stored in the memory 1302, thereby realizing the deep-sea anchor stability determination method, the deep-sea anchor embedment end position identification method, the deep-sea anchor stability determination method verification method, and the mooring parameter main control influencing factor determination method in the above method embodiments.

[0224] The memory 1302 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created by the processor 1301, etc. Furthermore, the memory 1302 may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, the memory 1302 may optionally include memory remotely located relative to the processor 1301, and these remote memories may be connected to the processor 1301 via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0225] The one or more modules are stored in the memory 1302. When executed by the processor 1301, they implement the above-mentioned method for determining the stability of deep-sea anchor piles, the method for identifying the embedded end position of deep-sea anchor piles, the verification method for determining the stability of deep-sea anchor piles, or the method for determining the main influencing factors of mooring parameters.

[0226] The specific details of the above-mentioned electronic device can be understood by referring to the relevant descriptions and effects in the method embodiments, and will not be repeated here.

[0227] This specification also provides a computer storage medium storing computer program instructions, which, when executed by a processor, implement the steps of the above-described method for determining the stability of deep-sea anchor piles, the method for identifying the embedded end position of deep-sea anchor piles, the verification method for determining the stability of deep-sea anchor piles, or the method for determining the main influencing factors of mooring parameters.

[0228] This specification also provides a computer program product, comprising a computer program that, when executed by a processor, implements the steps of the above-mentioned method for determining the stability of deep-sea anchor piles, the method for identifying the embedded end position of deep-sea anchor piles, the method for verifying the method for determining the stability of deep-sea anchor piles, or the method for determining the main influencing factors of mooring parameters.

[0229] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), random access memory (RAM), flash memory, hard disk drive (HDD), or solid-state drive (SSD), etc.; the storage medium can also include combinations of the above types of memory.

[0230] The various embodiments in this specification are described in a progressive manner. For the same or similar parts between the various embodiments, please refer to each other. The focus of each embodiment is to describe the differences from other embodiments.

[0231] The systems, devices, modules, or units described in the above embodiments can be implemented by computer chips or entities, or by products with certain functions.

[0232] For ease of description, the above devices are described separately by function as various units. Of course, in implementing this application, the functions of each unit can be implemented in one or more software and / or hardware.

[0233] As can be seen from the above description of the embodiments, those skilled in the art can clearly understand that this application can be implemented by means of software plus necessary general-purpose hardware platforms. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute certain parts of the methods of various embodiments of this application.

[0234] This application can be used in a wide variety of general-purpose or special-purpose computer system environments or configurations. For example: personal computers, server computers, handheld or portable devices, tablet devices, multiprocessor systems, microprocessor-based systems, set-top boxes, programmable consumer electronics devices, network PCs, minicomputers, mainframe computers, distributed computing environments including any of the above systems or devices, etc.

[0235] This application can be described in the general context of computer-executable instructions, such as program modules, that are executed by a computer. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform a specific task or implement a specific abstract data type. This application can also be practiced in distributed computing environments where tasks are performed by remote processing devices connected via a communication network. In distributed computing environments, program modules can reside in local and remote computer storage media, including storage devices.

[0236] Although this application has been described through embodiments, those skilled in the art will know that this application has many modifications and variations without departing from the spirit of this application, and it is intended that the appended claims cover such modifications and variations without departing from the spirit of this application.

Claims

1. A method for determining the stability of deep-sea anchor piles, characterized in that, include: For the engineering case where the mooring load acts on the middle part of the anchor pile, the differential equation for the lateral deflection control of the anchor pile on the seabed is constructed. The anchor pile is divided into an upper anchor pile and a lower anchor pile based on the point of application of the mooring load. The differential equation for the lateral deflection control is solved piecewise to obtain the displacement distribution function of the upper anchor pile and the lower anchor pile respectively. The location of the embedded end is calculated and identified based on the pile displacement distribution function of the upper and lower anchor piles; the embedded end is the location point on the pile body where the flexural displacement approaches zero, except for the pile end. The stability of the anchor pile is determined by the number of embedded ends.

2. The method according to claim 1, characterized in that, Determining the stability of the anchor pile based on the number of embedded ends includes: If there are two embedded ends, then the anchor pile has reached the target stable state of the engineering design. If the number of embedded ends is zero, the anchor pile is determined to be in an unstable state.

3. The method according to claim 1, characterized in that, When two embedded ends are identified, the method further includes: The total lateral bearing capacity of the anchor pile is calculated by integrating the soil reaction force in the region between the two fixed ends of the anchor pile. The formula for calculating the total lateral bearing capacity is: ， Among them, F L denoted as the total lateral bearing capacity, x1 as the coordinate of the upper fixed end, x2 as the coordinate of the lower fixed end, and p(x) as the soil reaction force at the position x on the anchor pile.

4. A method for identifying the embedded end position of a deep-sea anchor pile, characterized in that, include: For the engineering case where the mooring load acts on the middle part of the anchor pile, the differential equation for the lateral deflection control of the anchor pile on the seabed is constructed. The anchor pile is divided into an upper anchor pile and a lower anchor pile based on the point of application of the mooring load. The differential equation for the lateral deflection control is solved piecewise to obtain the displacement distribution function of the upper anchor pile and the lower anchor pile respectively. The location of the embedded end is calculated and identified based on the pile displacement distribution function of the upper and lower anchor piles; the embedded end is the location point on the pile body where the flexural displacement approaches zero, except for the pile end.

5. A verification device for a method of determining the stability of deep-sea anchor piles, characterized in that, A method for verifying the stability determination method of deep-sea anchor piles according to any one of claims 1 to 3; the verification equipment includes: The experimental test model includes multiple sets of simulated anchor piles with different geometric parameters, as well as a mooring system composed of anchor chains and polyester cables; The installation and environmental simulation system includes a soil box for simulating seabed soil, a vertical loading system for simulating anchor insertion and extraction, and a swing motor for applying periodic loads. The data acquisition system includes soil pressure sensors and acceleration sensors installed on the pile body of the simulated anchor pile, tension sensors installed at both ends of the mooring cable, displacement sensors for monitoring the displacement of the anchor pile, and a data acquisition instrument for collecting data from all sensors. Electronic equipment is used to verify the method for determining the stability of deep-sea anchor piles based on the collected data from various sensors, and / or to analyze the main influencing factors of mooring parameters and determine the optimal design range of the main influencing factors.

6. A verification method for determining the stability of deep-sea anchor piles, characterized in that, The verification equipment employs the deep-sea anchor pile stability determination method described in claim 5; the verification method includes: S21: After installing the sensors and completing the calibration according to the preset experimental plan, control the vertical pressing of the anchor pile into the simulated seabed soil to the design depth, and adjust the initial tension to the design value after connecting the mooring system; S22: Start the data acquisition system, control the swing motor to apply the preset load, and continuously and synchronously collect data on soil pressure, acceleration, tension at both ends of the mooring cable and displacement at the top of the anchor pile at each measuring point on the pile body. S23: Perform quadratic integration and filtering on the collected pile acceleration time history data to calculate the lateral displacement of each measuring point; automatically identify the fixed end position in the static experiment based on the displacement criterion, or identify the evolution law of the average fixed end and the peak fixed end in the dynamic experiment respectively; cross-validate the fixed end identification results using the synchronously collected earth pressure data. S24: Determine the effective stress zone of the pile body based on the identified fixed end position, and obtain the theoretically calculated lateral ultimate bearing capacity by integrating the earth pressure distribution curve within the effective stress zone; introduce the soil cyclic softening correction coefficient under dynamic working conditions to calculate the dynamic ultimate bearing capacity and the remaining ultimate bearing capacity; S25: Compare and analyze the theoretical calculation results of the fixed end position and the lateral bearing capacity with the experimental measurement results, calculate the relative error, and thus verify the accuracy of the method for determining the stability of deep-sea anchor piles; By changing at least one of the following parameters—pile diameter, pile length, anchor hole height, mooring angle, and initial tension—a new pre-set experimental scheme is formed. Steps S21-S25 are repeated to verify the universal applicability of the method for determining the stability of deep-sea anchor piles under different parameter conditions.

7. A method for determining the main influencing factors of mooring parameters, characterized in that, include: S31: Using the controlled variable method, multiple sets of comparative experiments were conducted to control the influence of at least one of the following on the stability of the anchor pile: pile diameter, pile length, mooring anchor height, mooring angle and initial tension. Data on pile earth pressure, acceleration, mooring cable tension and displacement were collected for each set of experiments. S32: Using the verification equipment described in claim 5, process multiple sets of experimental data with controlled variables to establish a quantitative relationship between parameters such as pile diameter, pile length, mooring anchor height, mooring angle, and initial tension, and the anchor pile embedment end position, lateral bearing capacity, cumulative deformation, and stiffness degradation rate; wherein, the embedment end position identification method of the deep-sea anchor pile described in claim 4 is used to identify the embedment end position. S33: Using sensitivity analysis, the influence of each parameter on the static stability and dynamic service performance of the anchor pile is quantified, and the key control parameters for controlling the stability of the anchor pile are identified. S34: Plot the influence curves of each parameter on the performance of the anchor pile, and analyze the effect of parameter changes on the formation conditions of double embedded ends, the effective stress zone range and bearing capacity. S35: Based on the influence of parameters, determine the optimal design range of anchor pile structure and mooring parameters under different engineering conditions to guide the engineering design of deep-water mooring anchor piles.

8. A device for determining the stability of deep-sea anchor piles, characterized in that, include: The construction unit is used to construct the lateral deflection control differential equation of the anchor pile on the seabed for the engineering condition of mooring load acting on the middle part of the anchor pile. The anchor pile is divided into upper anchor pile and lower anchor pile based on the point of application of mooring load. The lateral deflection control differential equation is solved segment by segment to obtain the pile displacement distribution function of the upper anchor pile and the lower anchor pile respectively. The identification unit is used to calculate and identify the position of the embedded end based on the pile displacement distribution function of the upper and lower anchor piles; the embedded end is the position point on the pile body where the flexural displacement approaches zero, except for the pile end. The first determining unit is used to determine the stability of the anchor pile based on the number of embedded ends.

9. A device for identifying the embedded end position of a deep-sea anchor pile, characterized in that, include: The construction unit is used to construct the lateral deflection control differential equation of the anchor pile on the seabed for the engineering condition of mooring load acting on the middle part of the anchor pile. The anchor pile is divided into upper anchor pile and lower anchor pile based on the point of application of mooring load. The lateral deflection control differential equation is solved segment by segment to obtain the pile displacement distribution function of the upper anchor pile and the lower anchor pile respectively. The identification unit is used to calculate and identify the position of the embedded end based on the pile displacement distribution function of the upper and lower anchor piles; the embedded end is the position point on the pile body where the flexural displacement approaches zero, except for the pile end.

10. A verification device for a method of determining the stability of deep-sea anchor piles, characterized in that, Verification equipment using the deep-sea anchor pile stability determination method according to claim 5; the device includes: The first control unit is used to control the vertical pressing of the anchor pile into the simulated seabed soil to the design depth after the sensor is installed and calibrated according to the preset experimental plan, and to adjust the initial tension to the design value after connecting the mooring system. The second control unit is used to start the data acquisition system, control the swing motor to apply a preset load, and continuously and synchronously collect data on soil pressure, acceleration, tension at both ends of the mooring cable, and displacement at the top of the anchor pile at each measuring point on the pile body. The first data processing unit is used to perform quadratic integration and filtering on the collected pile acceleration time history data, calculate the lateral displacement of each measuring point; automatically identify the fixed end position in the static experiment based on the displacement criterion, or identify the evolution law of the average fixed end and the peak fixed end in the dynamic experiment respectively; and cross-validate the fixed end identification results using the synchronously collected earth pressure data. The second data processing unit is used to determine the effective stress zone of the pile body based on the identified fixed end position, and to obtain the theoretically calculated lateral ultimate bearing capacity by integrating the earth pressure distribution curve within the effective stress zone; under dynamic working conditions, a soil cyclic softening correction coefficient is introduced to calculate the dynamic ultimate bearing capacity and the remaining ultimate bearing capacity. The comparison unit is used to compare and analyze the theoretical calculation results of the fixed end position and lateral bearing capacity with the experimental measurement results, calculate the relative error, and thus verify the accuracy of the method for determining the stability of deep-sea anchor piles. The scheme update unit is used to replace at least one of different pile diameter, pile length, anchor hole height, mooring angle and initial tension to form a new preset experimental scheme, so that the first control unit, the second control unit, the first data processing unit, the second data processing unit and the comparison unit can repeatedly execute it to verify the universal applicability of the deep-sea anchor pile stability determination method under different parameter conditions.

11. A device for determining the main influencing factors of mooring parameters, characterized in that, include: The third control unit is used to conduct multiple comparative experiments on the influence of at least one of the following on the stability of the anchor pile using the controlled variable method: pile diameter, pile length, mooring anchor height, mooring angle and initial tension. The unit collects data on the soil pressure, acceleration, mooring cable tension and displacement of the pile body in each experiment. The third data processing unit is used to process multiple sets of experimental data of controlled variables through the verification equipment described in claim 5, and to establish a quantitative relationship between parameters such as pile diameter, pile length, mooring anchor height, mooring angle, and initial tension and the anchor pile embedment end position, lateral bearing capacity, cumulative deformation and stiffness degradation rate; wherein, the embedment end position identification method of deep-sea anchor pile described in claim 4 is used to identify the position of the embedment end. The fourth data processing unit is used to quantify the influence of each parameter on the static stability and dynamic service performance of the anchor pile using sensitivity analysis methods, and to identify the key control parameters for controlling the stability of the anchor pile. The analysis unit is used to plot the influence curves of various parameters on the performance of anchor piles, and to analyze the effect of parameter changes on the formation conditions of double embedded fixed ends, the effective stress zone range and bearing capacity. The second determining unit is used to determine the optimal design range of anchor pile structure and mooring parameters under different engineering conditions based on the parameter influence law, so as to guide the engineering design of deep-water mooring anchor piles.

12. An electronic device, characterized in that, include: A memory and a processor, the processor and the memory being communicatively connected to each other, the memory storing computer instructions, the processor executing the computer instructions to implement the method of any one of claims 1-4 and 6-7.

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