Towing anchor suitable for offshore platform mooring system and method for evaluating load bearing performance thereof

Abstract

The application provides a towing anchor suitable for a mooring system of an offshore platform and a method for evaluating the carrying capacity of the towing anchor, and belongs to the technical field of offshore engineering. The anchor plate of the towing anchor adopts a folded wing flat plate structure, a main flat plate and wing plates folded downward on both sides are arranged, and a baffle with a fan-shaped protrusion is arranged at the tail of the anchor plate corresponding to the main flat plate and the two wing plates. The evaluation method constructs a coupled deformation numerical model of independent modeling of components, obtains full-process simulation data through staged numerical calculation, calculates a comprehensive performance index through quantitative indexes combined with adaptive weights, and completes hierarchical evaluation. The application enhances the passive resistance of the tail soil body and improves the single-anchor carrying efficiency and the stability of the penetration posture by using the folded wing anchor plate combined with the three fan-shaped protrusions. The application obtains actual performance evaluation results and improves the engineering adaptability by using the coupled deformation numerical model of independent modeling of components and taking the connection angle as a variable, combined with the staged calculation and multi-index comprehensive evaluation method.

Description

Technical Field

[0001] This application belongs to the field of marine engineering technology, specifically relating to a towed anchor suitable for offshore platform mooring systems and a method for evaluating its load-bearing capacity. Background Technology

[0002] Floating offshore platforms represent the main direction of development for deep-sea equipment, and the supporting mooring and anchoring systems are the foundation for ensuring the safety of platform operations.

[0003] Among them, towed anchors are widely used in mooring systems of floating structures such as floating wind turbines and deep-sea oil and gas platforms due to their advantages of simple installation, high anchoring force, and low environmental disturbance. The ultimate bearing capacity of existing towed anchors is usually directly related to the anchor body's self-weight and structural dimensions. To meet the mooring requirements of large tonnage vessels, it is often necessary to increase the mass and volume of the anchor body, which leads to increased transportation and hoisting difficulties and increased installation costs. The bearing efficiency of small-mass anchor bodies is difficult to meet the high requirements of deep-sea engineering.

[0004] The existing towed anchor plate configuration has limited ability to mobilize and utilize seabed soil, and the passive resistance of the soil in the anchor tail area is not fully utilized, leaving room for improvement in the efficiency of the single anchor bearing surface. Furthermore, the design optimization process for towed anchors lacks evaluation results that accurately reflect actual performance, making them prone to insufficient attitude stability in practical applications. This leads to discrepancies between the actual anchor penetration depth and bearing capacity, as well as insufficient engineering adaptability to different seabed conditions.

[0005] In summary, existing towed anchors suffer from technical problems such as insufficient lightweight design and inadequate load-bearing capacity. Summary of the Invention

[0006] This application addresses the problems existing in the prior art by providing a towed anchor and its load-bearing performance evaluation method that takes into account both soil resistance utilization efficiency and penetration attitude stability, and is applicable to offshore platform mooring systems.

[0007] To achieve the above objectives, the technical solution adopted in this application is as follows: On the one hand, this application provides a towed anchor suitable for offshore platform mooring systems, which includes an anchor shank and an anchor plate; the anchor shank is connected to the anchor plate; The anchor plate is a folded-wing flat plate structure, with a main flat plate and two downward-folding wing plates on both sides; The anchor plate is provided with three fan-shaped protruding baffles at its tail, corresponding to the main plate and the two wing plates respectively; The baffle is set at an angle.

[0008] Furthermore, the three fan-shaped protruding baffles are distributed on the same plane, and adjacent baffles are connected by concave arc portions.

[0009] Furthermore, the effective width of the baffle for: ; In the formula, the effective width The equivalent soil width is perpendicular to the towing direction; The soil weight, This is the passive earth pressure coefficient. To increase the load-bearing ratio, The depth of the anchor in the soil. This refers to the anchor body's bearing capacity without a tail baffle.

[0010] Furthermore, the lower surface of the anchor plate is provided with at least two vertical guide plates; The vertical guide plate is provided at the junction of the main plate and the wing plate.

[0011] Furthermore, the lower end of the anchor shank has multiple connection holes arranged along its length, and the upper part of the anchor plate is provided with corresponding fixing holes; The anchor shank and the anchor plate are connected by a connecting hole and a fixing hole to adjust the connection angle.

[0012] Furthermore, the anchor shank is a vertical single-plate structure; The thickness of the anchor shank increases from top to bottom; The front side of the anchor shank is provided with a toothed structure, a stepped structure, or an equally spaced spike structure.

[0013] Furthermore, the leading edge of the anchor plate has a W-shaped structure; The leading edge of the main plate has a V-shaped structure, and the connection between the main plate and the two side wing plates is provided with a sharp corner. The pointed corner is inclined downwards along the horizontal.

[0014] On the other hand, this application also provides a method for evaluating the load-bearing capacity of a towed anchor, the main steps of which include: Under the same conditions, numerical calculation models of coupled deformation of the dragged anchor to be evaluated and the reference dragged anchor were constructed respectively. When modeling, each structural component of the dragged anchor was treated as an independent component, and the connection angle between the anchor plate and the anchor shank was used as a model variable. A phased numerical calculation is performed on the coupled deformation numerical calculation model, and simulation data of the entire drag-in process is obtained; the phases of the phased numerical calculation include the initial anchoring phase, the soil contact equilibrium phase, and the drag-in phase. Based on the simulation data, the effective weight ratio, normalized penetration depth, penetration stability coefficient, and installation energy efficiency coefficient were calculated respectively. Based on the preset adaptive weighting coefficients, the corresponding ratios of the effective gripping weight ratio, normalized penetration depth, penetration stability coefficient, and installation energy efficiency coefficient of the to be evaluated towed anchor and the benchmark towed anchor are weighted and summed to obtain the comprehensive performance index. Based on the grading standard corresponding to the comprehensive performance index, the comprehensive performance evaluation result of the towed anchor to be evaluated is output.

[0015] Furthermore, the coupled deformation numerical calculation model is constructed using the coupled Euler-Lagrange finite element method; In the coupled deformation numerical calculation model, a contact interface is provided between the anchor body and the soil body, and the contact interface adopts a friction contact model or an adhesive contact model. The simulated data includes attitude angle data; before calculating the penetration stability coefficient, the attitude angle data is resampled at equal time intervals, outlier removal is performed, and filtering is performed sequentially, and the attitude angle data of the installation stage before the stable towing stage is extracted for the calculation of the penetration stability coefficient. The penetration stability coefficient is calculated based on the ratio of the standard deviation of the attitude angle fluctuation during the installation phase to the allowable attitude angle fluctuation value.

[0016] Furthermore, the adaptive weight coefficients are obtained through expert weighting or entropy weighting, and the sum of the values ​​of the adaptive weight coefficients is 1.

[0017] Compared with the prior art, this application has the following advantages: This application enhances the passive resistance of the soil at the tail end by adopting a folded-wing anchor plate and arranging three fan-shaped protruding baffles at the tail end of the anchor plate, thereby improving the single anchor bearing efficiency. Under the same bearing requirements, it reduces the mass and volume of the anchor body, balancing lightweight and high bearing capacity, while improving penetration attitude stability and reducing performance dispersion. Furthermore, by adopting a coupled deformation numerical model with independent modeling of each component and connection angle as a variable, combined with staged calculation and multi-index comprehensive evaluation, it obtains realistic performance evaluation results, thereby improving the engineering adaptability of the towed anchor. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a perspective view of the towed anchor in a specific embodiment of this application; Figure 2 This is a top view of the towed anchor in a specific embodiment of this application; Figure 3 This is a side view of the towed anchor in a specific embodiment of this application; Figure 4 This is a rear view of the towed anchor in other embodiments of this application; Figure 5 This is a side view of the anchor shank in a specific embodiment of this application; Figure 6 This is a rear view of the anchor shank in a specific embodiment of this application; Figure 7 This is a diagram showing the anchor adjustment angle in a specific embodiment of this application; Figure 8 This is a top view of the anchor plate in a specific embodiment of this application; Figure 9 This is a schematic diagram of the anchor plate dimensions in a specific embodiment of this application; Figure 10 This is a side view of the vertical guide plate in a specific embodiment of this application; Figure 11 This is a rear view of the vertical guide plate in a specific embodiment of this application; Figure 12 This is a projection view of the fan-shaped protruding baffle in a specific embodiment of this application; Figure 13 This is a side view of the fan-shaped protruding baffle in a specific embodiment of this application.

[0020] In the picture: 1. First connecting part; 101. Handle body; 102. Spike; 103. Anchor ring; 1011. Anchor hole; 2. Second connecting part, 201, first leg, 202, second leg, 2011, pivot hole, 2021, connecting hole position; 3. Anchor plate; 301. Main plate; 302. Wing plate; 303. Main plate raised baffle; 304. Wing plate raised baffle; 305. Vertical guide plate. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of 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, not all of them. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0023] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0024] In addition, in the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0025] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature.

[0026] It is worth noting that, unless otherwise specified, the methods used in this application are all conventional methods; and the raw materials and equipment used are all conventional commercially available products, and their sources are not specifically limited.

[0027] On the one hand, such as Figures 1-4 As shown, this embodiment provides a towed anchor suitable for offshore platform mooring systems, including an anchor shank and an anchor plate 3, with the anchor shank connected to the anchor plate 3.

[0028] The anchor plate 3 is a folded-wing flat plate structure, comprising a main flat plate 301 and two downward-folding wing plates 302 on both sides. Three fan-shaped protruding baffles are provided at the tail of the anchor plate 3, corresponding to the main flat plate 301 and the two wing plates 302 respectively, and the fan-shaped protruding baffles are inclined. Specifically, the fan-shaped protruding baffles are inclined backward in the opposite direction of the anchor body's dragging, and the angle between the baffle surface and the plane of the main flat plate 301 ranges from 20° to 60°; in this embodiment, the preferred angle range is 30° to 45°. The inclined angle of the fan-shaped protruding baffles ensures that the baffles have sufficient effective soil projection area, fully mobilizing the passive resistance of the tail soil to improve bearing capacity; on the other hand, it avoids an excessively large soil-facing area on the front of the baffles, preventing a significant increase in resistance during dragging and penetration, thus balancing penetration efficiency and bearing capacity gain. Furthermore, the three fan-shaped protruding baffles are integrally formed and distributed on the same plane, with adjacent baffles connected by concave arc portions.

[0029] Specifically, in this embodiment, the three fan-shaped protrusions include a main plate protrusion baffle 303 and two wing plate protrusion baffles 304. The main plate protrusion baffle 303 corresponds to the main plate 301, and the two wing plate protrusion baffles 304 correspond to the two side wing plates 302 respectively. The leading edge of the anchor plate 3 has a W-shaped structure, the leading edge of the main plate 301 has a V-shaped structure, and the connection between the main plate 301 and the two side wing plates 302 is provided with a pointed corner, which is inclined downwards horizontally.

[0030] Specifically, in this embodiment, the pointed corner of the front end of the anchor plate 3 adopts a streamlined anchor tip configuration with bilateral symmetry. The joint area between the anchor tip surface and the anchor plate 3 is rounded to reduce the frictional resistance coefficient of the soil-metal interface, improve the soil breaking efficiency when the anchor body penetrates the soil, and enhance the attitude stability of the anchor body on the seabed surface.

[0031] Taking a specific set of structural dimensions as an example, refer to Figures 5-7 As shown, the anchor shank is a vertical single-plate structure, and the thickness of the anchor shank increases from the top to the bottom. The front side of the anchor shank is provided with a toothed structure, a stepped structure, or an evenly distributed spike structure.

[0032] Specifically, the anchor shank in this embodiment includes a first connecting part 1 and a second connecting part 2, forming an integral force transmission structure. The first connecting part 1 includes a handle 101, which is inclined and has a 10mm anchor hole 1011 at its top for threading an anchor ring 103, thereby connecting the shackle and the anchor chain. The front side of the handle 101 has five equally spaced spikes 102 as a soil-breaking structure. In this embodiment, there are five spikes 102 distributed in the middle of the anchor shank, enhancing the soil-breaking ability during anchor penetration and reducing soil resistance. In this embodiment, the anchor shank sketch is first topologically optimized, and then the structure is refined based on the optimization results, adding details such as serrations, gradient thickness, and connecting holes. The lightweight design utilizes the topology optimization module in the Altair Inspire simulation software to simulate the load position and direction of the anchor shank in actual engineering, performing stress analysis on the anchor shank to obtain the overall stress distribution. Redundant materials are removed while meeting the load-bearing requirements, reducing the overall mass of the anchor body.

[0033] The lower end of the anchor shank has multiple connecting holes arranged along its length, and the upper part of the anchor plate 3 has corresponding fixing holes. The anchor shank and the anchor plate 3 are connected through the connecting holes and fixing holes to adjust the connection angle. Specifically, in this embodiment, the second connecting part 2 is located at the lower end of the handle 101 and has an inverted two-pronged structure, including a first leg 201 and a second leg 202. The first leg 201 is provided with a pivot hole 2011, and the second leg 202 is provided with multiple sets of connecting holes 2021. By engaging the connecting holes 2021 at different positions with a pin, the connection angle between the anchor shank and the anchor plate 3 can be adjusted to meet different engineering requirements. The distance between the connecting holes 2021 and the pivot holes 2011 is... The diameter is 75mm. Furthermore, the connecting hole 2021 consists of three 5mm holes, which are fixed to different holes on the rear side by bolts. This allows adjustment of the angle between the anchor plate 3 and the anchor shank, with the corresponding angles being... , , Thickness of the opening area at the lower end of the anchor shank The thickness of the front shackle connection area is set to 10mm. The thickness is set to 5mm, with a gradient transition design in the middle of the anchor shank, smoothly increasing from 5mm to 10mm to avoid excessive stress in the connection area and resulting in yielding deformation. The overall length of the anchor shank... Set to 320mm, overall height Set to 160mm.

[0034] refer to Figure 8 and Figure 9 As shown, the overall width of anchor plate 3 The width is set to 300mm, where the main plate is 301mm wide. The width of one side of the two wing plates 302 is 150mm. The anchor plate is designed to be 75mm thick. The length is 5mm; the main plate 301 has a length of 5mm. The distance from the bottom of the V-shape to the tail end of the main plate 301 is equal to the width of the main plate 301, and is set as follows: The length of the front anchor tip Set as The angle at which the two side wing plates 302 bend downwards along the central plane is... Two shaft supports are provided at the central axis position of anchor plate 3. A set of connecting holes, including four bolt holes, is machined on the shaft supports to connect anchor plate 3 to anchor shank. Two of the holes are 20mm × 10mm in size. The spacing between the holes on the two shaft supports is the same as the spacing between connecting hole 2021 and rotating shaft hole 2011. .

[0035] Combination Figure 10 and Figure 11 As shown, the lower surface of the anchor plate 3 is provided with at least two vertical guide plates 305, and the junction of the main plate 301 and the wing plate 302 is provided with vertical guide plates 305.

[0036] Specifically, in this embodiment, two vertical guide plates 305 are provided. The vertical guide plates 305 are streamlined in shape, running horizontally across the entire lower surface of the anchor plate 3 from the anchor tip to the rear. The front end has a sharp angle structure, and the rear end tends to be flat. The total length of the vertical guide plates 305 is... Set to the same effective length as anchor plate 3. ,thickness Set as The front end is horizontally downward. The direction extends forward by a length of The sharp corner, with the middle of the guide plate being the widest point, is set as follows: This position corresponds vertically to the tail of the anchor tip. The width gradually decreases from the widest point towards the front sharp corner, while remaining constant towards the rear. The tail end face of the vertical guide plate 305 is perpendicular to the horizontal direction. Angle.

[0037] Effective width of the fan-shaped raised baffle for: ; In the formula, the effective width The equivalent soil width is perpendicular to the towing direction; The soil weight, This is the passive earth pressure coefficient. To increase the load-bearing ratio, The depth of the anchor in the soil. This refers to the anchor body's bearing capacity without a tail baffle.

[0038] Specifically, the design of the tail baffle in this embodiment differs from the conventional approach of minimizing tail resistance in traditional towed anchors. The raised tail structure may increase soil resistance during anchor towing, hindering anchor penetration. In contrast, the tail baffle design in this embodiment increases the effective soil contact area without impeding penetration. The specific design is as follows: Let the effective area of ​​the tail baffle be The effective bearing area of ​​the anchor plate is The rear fender area is greater than Defined as: ; when When the tail section is too small, the tail baffle cannot effectively mobilize the soil resistance at the tail, thus having limited effect on improving bearing capacity and attitude stability; when If the tail baffle is too large, it will significantly increase the penetration resistance, making it difficult for the anchor body to penetrate.

[0039] Therefore, the area ratio of the three fan-shaped protruding baffles in this embodiment is determined by both the additional load-bearing ratio and the allowable penetration resistance. Let the additional load-bearing ratio of the tail baffle be... ,Right now ,in This refers to the anchor body's bearing capacity without a tail baffle.

[0040] In this embodiment, the target additional load-bearing ratio of the baffle is taken as... The design objective of the fan-shaped protrusion baffle is to increase the anchor's bearing capacity by approximately 20% compared to when the tail fan-shaped protrusion is not present, without significantly increasing the penetration resistance. The additional bearing capacity of the tail baffle can be approximated as: ; In the formula, The effective width of the tail baffle is denoted by , and the equivalent soil-bearing width of the tail baffle perpendicular to the towing direction is denoted by .

[0041] This expression is obtained by integrating the passive earth pressure on the soil in front of the baffle along the depth of penetration. Depth passive earth pressure at the location It can be represented as: ; The additional load-bearing capacity of the tailgate for: ; Substitution We can obtain: ; After simplification, we get: ; By combining the definition of the target additional load ratio, the effective width parameter of the tail baffle can be calculated.

[0042] Furthermore, in this embodiment, the design area of ​​the three fan-shaped raised baffles is 11250 mm². 2 The effective bearing area of ​​the anchor plate body is 22500 mm². 2 The corresponding tailgate area ratio is 0.5. Combined with... Figure 12 and Figure 13 As shown, taking the main plate protruding baffle 303 as an example, the effective width is known. After setting the curvature, calculate the maximum projected width. Minimum projection width is 35mm. The thickness of the baffle is 25mm. Set to 5mm; then adjust according to the actual width of the main tablet 301. And the actual width of wing plate 302 The complete structural dimensions of the fan-shaped protrusion can be determined by the angle of inclination of the baffle.

[0043] The three fan-shaped raised baffles are arranged symmetrically. Besides increasing the bearing area, this also improves the attitude stability during penetration. When the anchor body deflects during towing, the contact area between the left and right baffles and the soil differs, generating asymmetrical earth pressure and forming a reverse restoring moment, expressed as: ; In the formula, The attitude-restoring torque generated by the tailgate; The difference in soil reaction force on the left and right tail plates; This is the lever arm from the point of application of the soil reaction force to the centerline of the anchor body. This restoring moment can suppress the lateral deflection and pitch instability of the anchor body during penetration, and improve the self-adjusting balance during the towing installation process.

[0044] The soil reaction forces on the left and right sides are obtained by integrating the soil contact pressure on the surface of the tail baffle, specifically as follows: ; ; ; In the formula, and These represent the soil reactions acting on the left and right baffles, respectively. and These are the effective soil-receiving areas of the left and right baffles, respectively. The distribution of soil contact pressure on the surface of the tail baffle.

[0045] Lever arm from the point of application of the soil reaction force to the centerline of the anchor body l b Determined by the point of application of the resultant force of the soil reactions on both sides:

[0046] ; ; ; In the formula, and These are the lateral coordinates of the points of application of the resultant forces of the soil reaction forces at the left and right tail baffles, respectively.

[0047] In summary, the fan-shaped protrusion baffle in this embodiment does not simply increase the tail area, but rather forms a composite structure with three fan-shaped protrusions to improve load-bearing capacity and attitude adjustment. On the one hand, this structure can increase the effective contact area between the anchor tail and the seabed soil, improving the grip weight ratio; on the other hand, the symmetrical arrangement of the baffles can generate a restoring torque when the anchor body deflects, enhancing the directional stability and self-balancing ability of the anchor body during penetration.

[0048] On the other hand, this embodiment also provides a method for evaluating the load-bearing performance of a towed anchor, used to quantitatively evaluate the comprehensive performance of the aforementioned towed anchor, the main steps of which include: Under identical conditions, coupled deformation numerical calculation models for the towed anchor to be evaluated and the reference towed anchor were constructed separately. During modeling, each structural component of the towed anchor was treated as an independent part, and the connection angle between the anchor plate and the anchor shank was used as a model variable. Before the evaluation, the effective unit weight, internal friction angle, cohesion, elastic modulus, shear modulus, interfacial friction coefficient, and undrained shear strength parameters of the seabed soil in the target sea area were obtained through cone penetration test (CPT), standard stress path triaxial test, and direct shear test. Traditional towed anchors or existing engineering anchor types were selected as reference objects. Under the same seabed soil conditions, towing speed, towing angle, and installation boundary conditions, coupled large deformation numerical calculation models of the anchor-chain-soil of the anchor to be evaluated and the reference anchor were established separately. Furthermore, the coupled deformation numerical calculation models were constructed using the coupled Eulerian-Lagrangian (CEL) finite element method.

[0049] In the coupled deformation numerical calculation model, a contact interface is set between the anchor body and the soil. The contact interface adopts a friction contact model or an adhesive contact model to describe the shearing, compression, and separation processes between the anchor body surface and the seabed soil during towing. In the modeling process, the anchor plate, anchor shank, bottom vertical guide plate, tail baffle, and anchor chain are modeled as independent functional components. The adjustable angle between the anchor plate and the anchor shank is used as a model variable. The anchor plate connection hole is used as the reference hole. Different adjustment holes at the lower end of the anchor shank correspond to different connection positions. Each set of connection hole positions corresponds to an angle between the anchor plate and the anchor shank. Corresponding calculation examples are established to obtain the performance parameters under different angles and determine the optimal connection scheme.

[0050] A phased numerical calculation was performed on the coupled deformation numerical calculation model to obtain simulation data of the entire towed penetration process. The phased numerical calculation included the initial anchoring stage, the soil contact equilibrium stage, and the towed penetration stage. In the initial anchoring stage, the towed anchor was placed above the seabed surface, allowing it to contact the soil under its own weight. In the soil contact equilibrium stage, the anchor body and the seabed soil reached an initial contact stability state, and the initial anchor body attitude and initial contact pressure were obtained. In the towed penetration stage, towed displacement was applied to the end of the anchor chain to simulate the entire process of the anchor body gradually penetrating, rotating, and reaching a stable embedded state.

[0051] Based on simulation data, the effective grip weight ratio, normalized penetration depth, penetration stability coefficient, and installation energy efficiency coefficient are calculated. After running the numerical model, the bearing capacity-displacement curve, penetration depth, attitude angle-time curve, tail baffle contact pressure distribution, and anchor chain tension variation curve of the anchor body during the towing process are obtained. Furthermore, the simulation data in this embodiment includes attitude angle data. Before calculating the penetration stability coefficient, the attitude angle data is sequentially resampled at equal time intervals, outlier removal is performed, and sliding median filtering or low-pass filtering is applied. Combined with the bearing capacity change rate, penetration depth change rate, and anchor chain tension fluctuation amplitude, it is used to identify whether the towed anchor has entered the stable towing stage. The attitude angle data of the installation stage before the stable towing stage is extracted for the calculation of the penetration stability coefficient.

[0052] The penetration stability coefficient is calculated based on the ratio of the standard deviation of the attitude angle fluctuation during the installation phase to the allowable attitude angle fluctuation value, which ranges from 3° to 5°. Therefore, the specific calculation is as follows: Calculate the effective holding weight ratio of the towed anchor. Consider the buoyancy of the anchor body underwater and the effective self-weight of the anchor body. The expression is:

[0053] In the formula, The density of the anchor material. The density of seawater, For the anchor body volume, This is the acceleration due to gravity.

[0054] Effective grip weight ratio of anchor body The expression is:

[0055] In the formula, This refers to the load-bearing capacity of the towed anchor.

[0056] Calculate the normalized embedment depth of the towed anchor. The expression is:

[0057] In the formula, The depth of penetration into the soil when the new type of towed anchor reaches a stable embedded state; This is the characteristic width of the anchor plate, which is generally taken as the maximum width of the towed anchor.

[0058] Calculate the penetration stability coefficient of the towed anchor. The smaller the attitude angle fluctuation of the anchor body during towed installation, the more stable its penetration process. Define the penetration stability coefficient as the attitude stability coefficient of the towed anchor. The expression is:

[0059] In the formula, The standard deviation of the anchor body attitude angle fluctuation during the penetration process; The allowable attitude angle fluctuation value ranges from 3° to 5°.

[0060] The dragging anchor tail baffle of this application generates a restoring torque when the anchor body deflects, and the restoring torque suppresses the deflection of the anchor body. The penetration stability coefficient in step 5 is calculated from the standard deviation of the attitude angle fluctuation after the restoring torque suppresses it.

[0061] Calculate the installation energy efficiency coefficient. The lower the energy consumption required for the anchor body during towing installation, the higher its installation efficiency. Define the towing anchor installation energy efficiency coefficient. The expression is: In the formula, For the towing anchor bearing capacity; The drag distance at which the anchor body reaches a stable embedded state; This is the drag force function that varies with the dragging distance during the dragging process; The work done by the dragging force during the installation of the anchor body.

[0062] Based on preset adaptive weighting coefficients, the corresponding ratios of the effective gripping weight ratio, normalized penetration depth, penetration stability coefficient, and installation energy efficiency coefficient of the towed anchor under evaluation and the benchmark towed anchor are weighted and summed to obtain a comprehensive performance index. According to the grading standard corresponding to the comprehensive performance index, the comprehensive performance evaluation result of the towed anchor under evaluation is output.

[0063] Among them, a comprehensive performance index is defined to comprehensively evaluate the anchor body's bearing capacity, penetration capacity, penetration stability, and installation energy efficiency. : In the formula, For the new type of towed anchor, the gripping weight ratio is improved; Compared to traditional towed anchors, this reduces the weight ratio. The dimensionless penetration depth of the new type of drag anchor; The dimensionless penetration depth of traditional towed anchors; The new type of anchor penetration stability coefficient; The penetration stability coefficient of a traditional anchor; The energy efficiency coefficient of the new type of anchor installation; The energy efficiency coefficient for traditional anchor installation. , , , These are the weighting coefficients for effective weight-to-weight ratio, normalized penetration depth, attitude stability, and installation energy efficiency, respectively, and they satisfy the following conditions: . , , , The weighting method can be determined using either expert weighting or entropy weighting, depending on the design requirements of different towed anchors; this is an adaptive weighting method. For the novel towed anchor in this embodiment, .

[0064] Evaluate the overall performance of the towed anchor. Based on the overall performance index... I The new type of towed anchor was graded and evaluated, as shown in Table 1: Table 1 Grading Evaluation Based on the obtained comprehensive performance index of the drag anchor I Based on this evaluation standard, the comprehensive evaluation results of the new towed anchor relative to the benchmark towed anchor are output.

[0065] Compared with existing evaluation methods that only use ultimate bearing capacity or maximum gripping weight ratio, this embodiment offers a more reliable evaluation method, specifically including: First, adopt an effective weight-to-weight ratio. Instead of the ordinary grip-weight ratio, it takes into account the buoyancy of seawater and can truly reflect the unit effective self-weight bearing efficiency of the anchor body in the underwater environment. Secondly, a normalized depth of burial is introduced. This allows for comparison of the penetration capabilities of anchors of different sizes and types on the same scale. Next, a penetration stability coefficient is introduced. The evaluation incorporates attitude fluctuations during towing installation to prevent schemes with high load-bearing capacity but unstable penetration from being mistakenly selected as the best option; and it also introduces an installation energy efficiency coefficient. The work done by external drag force is included in the evaluation, so that the evaluation results can simultaneously reflect the construction economy of the anchor foundation. Finally, by adopting adaptive weights, the contribution of each indicator can be adjusted according to engineering needs, avoiding evaluation bias caused by fixed weights.

[0066] Comparative Example 1; The superior performance of the novel towing anchor was verified by comparing it with traditional towing anchors, such as Hall anchors.

[0067] First, a numerical calculation model for anchor dragging installation is constructed. The novel dragging anchor model is shown in the above embodiment, with a material density of [missing information]. elastic modulus is taken Poisson ratio Feature width B It is 0.3m long and has a volume of approximately 550cm³. 3The mass is approximately 4.3 kg; the Hall anchor model is a traditional structure under the same conditions, i.e., the material density is... elastic modulus is taken Poisson ratio Feature width B It is 0.3m long and has a volume of approximately 1570cm³. 3 It weighs approximately 12.3 kg.

[0068] The parameters of the simulated environment are: sand density. elastic modulus Poisson's ratio The internal friction angle is 30°, and the cohesion is 1 kPa. The dragging speed is 300 mm / s.

[0069] The numerical model calculation results show that the anchor bearing capacity of the towing anchor in this application is... burial depth Standard deviation of anchor body attitude angle fluctuation during penetration process σ θ =2°, the work done by the dragging force during the anchor installation process. For Hall anchors, anchor bearing capacity burial depth Standard deviation of anchor body attitude angle fluctuation during penetration process σ θ =4°, the work done by the dragging force during the anchor installation process. Allowable attitude angle fluctuation value It is 5°.

[0070] Therefore, the evaluation methods used in this application are as follows: Regarding the towing anchor in this application: ; ; ; ; Compared to traditional Hall anchors: ; ; ; ; The comprehensive comparison is shown in Table 2. Table 2 Evaluation Results Furthermore, the comprehensive performance index was calculated. : ; According to the evaluation criteria, The overall performance of the novel towing anchor proposed in this application is rated as excellent.

[0071] To demonstrate that the evaluation method of this application is superior to existing methods, this comparative example further compares it with existing ultimate bearing capacity evaluation methods and maximum grip-weight ratio evaluation methods, as shown in Table 3 below: Table 3 Comparison Results The above comparison shows that existing ultimate bearing capacity evaluation methods can only conclude that the bearing capacity is improved, and the maximum gripping weight ratio evaluation method can only conclude that the bearing efficiency per unit weight is improved, but cannot determine whether there are potential problems such as insufficient penetration, excessive attitude fluctuations during penetration, or excessive installation energy consumption in the anchor body. The method in this application incorporates four types of indicators under the same evaluation framework, indicating that the new towed anchor does not sacrifice penetration performance, stability, or installation efficiency for high bearing capacity. Therefore, the evaluation method in this application can avoid misjudgments caused by single-indicator evaluation, and the evaluation conclusions are more scientific and reliable.

[0072] Finally, it should be noted that the above content is only used to illustrate the technical solution of this application, and is not intended to limit the scope of protection of this application. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of this application shall not depart from the substance and scope of the technical solution of this application.

Claims

1. A towed anchor suitable for offshore platform mooring systems, comprising an anchor shank and an anchor plate; the anchor shank is connected to the anchor plate; Its features are, The anchor plate is a folded-wing flat plate structure, with a main flat plate and two downward-folding wing plates on both sides; The anchor plate is provided with three fan-shaped protruding baffles at its tail, corresponding to the main plate and the two wing plates respectively; The baffle is set at an angle.

2. The towing anchor according to claim 1, characterized in that, The three fan-shaped raised baffles are distributed on the same plane, and adjacent baffles are connected by concave arc portions.

3. The towing anchor according to claim 2, characterized in that, The effective width of the baffle for: ； In the formula, the effective width The equivalent soil width is perpendicular to the towing direction; The soil weight, This is the passive earth pressure coefficient. To increase the load-bearing ratio, The depth of the anchor in the soil. This refers to the anchor body's bearing capacity without a tail baffle.

4. The towing anchor according to claim 1, characterized in that, The lower surface of the anchor plate is provided with at least two vertical guide plates; The vertical guide plate is provided at the junction of the main plate and the wing plate.

5. The towing anchor according to claim 1, characterized in that, The lower end of the anchor shank has multiple connection holes arranged along its length, and the upper part of the anchor plate has corresponding fixing holes. The anchor shank and the anchor plate are connected by a connecting hole and a fixing hole to adjust the connection angle.

6. The towing anchor according to claim 1, characterized in that, The anchor is a vertical single-plate structure; The thickness of the anchor shank increases from top to bottom; The front side of the anchor shank is provided with a toothed structure, a stepped structure, or an equally spaced spike structure.

7. The towing anchor according to claim 1, characterized in that, The leading edge of the anchor plate has a W-shaped structure; The leading edge of the main plate has a V-shaped structure, and the connection between the main plate and the two side wing plates is provided with a sharp corner. The pointed corner is inclined downwards along the horizontal.

8. A method for evaluating the load-bearing capacity of a towed anchor, characterized in that, include: Under the same conditions, numerical calculation models of coupled deformation of the dragged anchor to be evaluated and the reference dragged anchor were constructed respectively. When modeling, each structural component of the dragged anchor was treated as an independent component, and the connection angle between the anchor plate and the anchor shank was used as a model variable. A phased numerical calculation is performed on the coupled deformation numerical calculation model, and simulation data of the entire drag-in process is obtained; the phases of the phased numerical calculation include the initial anchoring phase, the soil contact equilibrium phase, and the drag-in phase. Based on the simulation data, the effective weight ratio, normalized penetration depth, penetration stability coefficient, and installation energy efficiency coefficient were calculated respectively. Based on the preset adaptive weighting coefficients, the corresponding ratios of the effective gripping weight ratio, normalized penetration depth, penetration stability coefficient, and installation energy efficiency coefficient of the to be evaluated towed anchor and the benchmark towed anchor are weighted and summed to obtain the comprehensive performance index. Based on the grading standard corresponding to the comprehensive performance index, the comprehensive performance evaluation result of the towed anchor to be evaluated is output.

9. The method for evaluating the load-bearing capacity of a towed anchor according to claim 8, characterized in that, The coupled deformation numerical calculation model is constructed using the coupled Euler-Lagrange finite element method; In the coupled deformation numerical calculation model, a contact interface is provided between the anchor body and the soil body, and the contact interface adopts a friction contact model or an adhesive contact model. The simulated data includes attitude angle data; before calculating the penetration stability coefficient, the attitude angle data is resampled at equal time intervals, outlier removal is performed, and filtering is performed sequentially, and the attitude angle data of the installation stage before the stable towing stage is extracted for the calculation of the penetration stability coefficient. The penetration stability coefficient is calculated based on the ratio of the standard deviation of the attitude angle fluctuation during the installation phase to the allowable attitude angle fluctuation value.

10. The method for evaluating the load-bearing capacity of a towed anchor according to claim 8, characterized in that, The adaptive weighting coefficients are obtained through expert weighting or entropy weighting, and the sum of the values ​​of the adaptive weighting coefficients is 1.

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