A servo shaft force dynamic adjustment method and system based on foundation pit displacement feedback

Abstract

The application provides a servo axial force dynamic adjustment method and system based on foundation pit displacement feedback, relates to the technical field of foundation pit engineering safety control, and solves the technical problem that the axial force adjustment in the prior art cannot adapt to the support bearing capacity and the force transmission interface state. The method specifically comprises the following steps: obtaining the real-time rebound strength of the concrete support, performing hierarchical initial loading based on the strength grade reached by the real-time rebound strength, making the servo jack and the force transmission interface closely attached and establishing an initial axial force; obtaining the interface separation displacement of the force transmission interface; mapping the interface separation displacement to a plurality of preset displacement threshold intervals to determine the target displacement threshold interval in which the interface separation displacement is located; and based on the target displacement threshold interval, performing a corresponding axial force adjustment action, which includes at least one of positive compensation, pressure maintenance or gradient unloading. The application is used for adjusting the servo axial force.

Description

Technical Field

[0001] This application relates to the field of safety control technology for foundation pit engineering, and in particular to a servo axial force dynamic adjustment method and system based on foundation pit displacement feedback. Background Technology

[0002] In deep foundation pit engineering, concrete support servo systems are widely used to actively control the deformation of the retaining structure. Existing technologies often focus on emergency pressure relief and risk mitigation under extreme and dangerous conditions. For example, when monitoring data reaches a preset danger threshold, the axial force is gradually reduced according to a preset gradient to prevent sudden stress changes. However, during the conventional construction phase of foundation pit excavation and support service, the bearing capacity of the concrete support dynamically changes with curing time, and the state of the force transmission interface between the support end and the retaining structure directly affects the axial force transmission efficiency. Existing control methods often neglect the coupling relationship between the strength growth law of concrete materials and the micro-deformation of the force transmission interface. They typically employ fixed loading programs or single axial force closed-loop control, leading to premature loading before the support strength meets the standard, causing structural damage, or blindly applying pressure when the force transmission interface separates, resulting in ineffective compensation or even exacerbating interface separation. This fails to achieve precise and proactive adaptation of axial force throughout the entire construction cycle. Therefore, existing technologies suffer from the technical problem that axial force adjustment cannot adapt to the bearing capacity of the support and the state of the force transmission interface. Summary of the Invention

[0003] This application provides a servo axial force dynamic adjustment method and system based on foundation pit displacement feedback, which solves the technical problem that the axial force adjustment in the prior art cannot adapt to the bearing capacity of the support and the state of the force transmission interface.

[0004] To achieve the above objectives, this application adopts the following technical solution: Firstly, a servo axial force dynamic adjustment method based on foundation pit displacement feedback is provided, comprising: acquiring the real-time rebound strength of the concrete support; performing graded initial loading based on the strength level achieved by the real-time rebound strength to make the servo jack closely adhere to the force transmission interface and establish an initial axial force; the force transmission interface is the physical contact area between the end bearing surface of the concrete support and the lateral force-bearing surface of the retaining structure; acquiring the interface separation displacement of the force transmission interface; the interface separation displacement is the relative displacement difference between the end of the concrete support and the retaining structure; mapping the interface separation displacement to a preset multi-level displacement threshold range to determine the target displacement threshold range in which the interface separation displacement is located; and performing corresponding axial force adjustment actions based on the target displacement threshold range, wherein the axial force adjustment actions include at least one of positive compensation, pressure maintenance, or gradient unloading.

[0005] The above scheme constructs a "strength-displacement" dual-dimensional feedback adjustment mechanism by combining the material strength properties of the concrete support with the geometric deformation properties of the force transmission interface. On the one hand, graded initial loading based on real-time rebound strength ensures the synchronization of axial force application timing with concrete bearing capacity, avoiding early overload damage. On the other hand, by mapping the interface separation displacement to multiple threshold ranges and executing differentiated adjustment actions, a refined response to the health status of the force transmission interface is achieved. This not only actively compensates for axial force loss under safe fit but also promptly stops damage when interface separation is severe, solving the problem that traditional single axial force control modes cannot adapt to complex interface conditions.

[0006] In conjunction with the first aspect mentioned above, in one possible implementation, based on the strength level achieved by the real-time rebound strength, a graded initial loading is performed to ensure close contact between the servo jack and the force transmission interface and establish an initial axial force. This includes: when the real-time rebound strength reaches the first strength level, applying a preloaded axial force to eliminate the gap at the force transmission interface; when the real-time rebound strength successively reaches higher second and third strength levels, gradually increasing the initial axial force according to a preset grade difference; after each loading stage, monitoring the stress state of the force transmission system, and executing the next loading stage after confirming that there are no abnormalities.

[0007] In conjunction with the first aspect mentioned above, in one possible implementation, obtaining the interface separation displacement of the force transmission interface includes: acquiring lateral displacement data of the retaining structure and axial displacement data of the concrete support end by means of displacement monitoring components arranged on both sides of the force transmission interface; calculating the interface separation displacement based on the difference between the lateral displacement data and the axial displacement data; or, directly acquiring the gap width of the force transmission interface as the interface separation displacement by means of crack ranging sensors arranged at the force transmission interface.

[0008] In conjunction with the first aspect mentioned above, in one possible implementation, the interface separation displacement is mapped to a preset multi-level displacement threshold interval to determine the target displacement threshold interval in which the interface separation displacement falls. This includes: acquiring multiple preset separation thresholds; dividing the displacement range into multiple sequentially increasing displacement threshold intervals using the multiple separation thresholds; comparing the interface separation displacement with the multiple separation thresholds; and determining the displacement threshold interval into which the interface separation displacement falls as the target displacement threshold interval based on the comparison results. The target displacement threshold interval characterizes the severity of the separation of the force transmission interface.

[0009] In conjunction with the first aspect mentioned above, in one possible implementation, based on the target displacement threshold range, corresponding axial force adjustment actions are performed, including: when the target displacement threshold range is the first range, positive compensation is performed; the first range indicates that the force transmission interface is in a safe fit state; when the target displacement threshold range is the second range, the adjustment increment of positive compensation is reduced; the second range indicates that the force transmission interface is in a slightly disengaged state; when the target displacement threshold range is the third range, pressure holding is performed; the third range indicates that the force transmission interface is in a moderately disengaged state; when the target displacement threshold range is the fourth range, gradient unloading is performed; the fourth range indicates that the force transmission interface is in a severely disengaged state.

[0010] In conjunction with the first aspect mentioned above, in one possible implementation, the corresponding axial force adjustment action is performed, including: calculating the axial force adjustment increment based on the adjustment strategy corresponding to the target displacement threshold range; generating a control command containing the axial force adjustment increment and a preset loading or unloading rate; outputting the control command to the servo hydraulic pump station to drive the servo jack to perform the action; acquiring the axial force feedback value of the servo jack in real time, and triggering pressure stabilization self-locking when the axial force feedback value reaches the target axial force value.

[0011] In conjunction with the first aspect mentioned above, in one possible implementation, the method further includes: obtaining the lateral displacement deformation of the enclosure structure; determining whether the lateral displacement deformation exceeds a preset lateral displacement alarm threshold; if it exceeds the lateral displacement alarm threshold, triggering a joint adjustment mechanism to dynamically correct the axial force adjustment action determined based on the interface separation displacement.

[0012] In conjunction with the first aspect mentioned above, in one possible implementation, the axial force adjustment action determined based on the interface separation displacement is dynamically corrected, including: when the interface separation displacement is within the range corresponding to the pressure holding, and the lateral deformation exceeds the lateral displacement alarm threshold, the pressure holding axial force target value is dynamically increased according to the preset lateral displacement compensation gradient; when the lateral deformation is detected to fall back to a safe range, the pressure holding axial force target value is restored to the initial pressure holding value.

[0013] In conjunction with the first aspect mentioned above, in one possible implementation, the measurement accuracy of the interface separation displacement is not less than 0.01 mm, and when the interface separation displacement exceeds 25 mm, the unloading amplitude of the gradient unloading is 500 kN.

[0014] Secondly, a servo axial force dynamic adjustment system based on foundation pit displacement feedback is provided, comprising: an initial loading module for acquiring the real-time rebound strength of the concrete support, and performing graded initial loading based on the strength level achieved by the real-time rebound strength to ensure close contact between the servo jack and the force transmission interface and establish an initial axial force; the force transmission interface is the physical contact area between the end bearing surface of the concrete support and the lateral force-bearing surface of the retaining structure; a displacement acquisition module for acquiring the interface separation displacement of the force transmission interface; the interface separation displacement is the relative displacement difference between the end of the concrete support and the retaining structure; an interval mapping module for mapping the interface separation displacement to a preset multi-level displacement threshold interval to determine the target displacement threshold interval in which the interface separation displacement is located; and an adjustment control module for performing corresponding axial force adjustment actions based on the target displacement threshold interval, wherein the axial force adjustment actions include at least one of positive compensation, pressure maintenance, or gradient unloading.

[0015] The servo axial force dynamic adjustment method and system based on foundation pit displacement feedback provided in this application constructs a "strength-displacement" dual-dimensional feedback adjustment mechanism. It drives graded initial loading based on real-time rebound strength, so that the axial force application is synchronized with the concrete strength growth, avoiding early-age overload damage. By mapping the interface separation displacement to multi-level threshold ranges and matching differentiated adjustment strategies, it achieves adaptive response to the entire process of the force transmission interface from contact to separation. At the same time, it introduces a joint adjustment mechanism for lateral deformation, taking into account both the local interface state and the overall stability of the foundation pit, and provides continuous dynamic feedback adjustment covering the entire construction life cycle, effectively improving the control accuracy and safety of the servo system.

[0016] It should be understood that the descriptions of technical features, technical solutions, beneficial effects, or similar language in this application do not imply that all features and advantages can be achieved in any single embodiment. Rather, it is understood that the description of a feature or beneficial effect means that a specific technical feature, technical solution, or beneficial effect is included in at least one embodiment. Therefore, the descriptions of technical features, technical solutions, or beneficial effects in this specification do not necessarily refer to the same embodiment. Furthermore, the technical features, technical solutions, and beneficial effects described in this embodiment can be combined in any suitable manner. Those skilled in the art will understand that embodiments can be implemented without one or more specific technical features, technical solutions, or beneficial effects of a particular embodiment. In other embodiments, additional technical features and beneficial effects may be identified in specific embodiments that do not embody all embodiments. Attached Figure Description

[0017] Figure 1 A flowchart illustrating a servo axial force dynamic adjustment method based on foundation pit displacement feedback provided in this application embodiment; Figure 2A flowchart illustrating another servo axial force dynamic adjustment method based on foundation pit displacement feedback provided in this application embodiment; Figure 3 A flowchart illustrating another servo axial force dynamic adjustment method based on foundation pit displacement feedback provided in this application embodiment; Figure 4 This is a system architecture diagram of a servo axial force dynamic adjustment system based on foundation pit displacement feedback provided in an embodiment of this application. Detailed Implementation

[0018] In the description of this application, unless otherwise stated, " / " means "or," for example, A / B can mean A or B. "And / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, and B alone. Furthermore, "at least one" means one or more, and "multiple" means two or more. The terms "first," "second," etc., do not limit the quantity or order of execution, and "first," "second," etc., do not necessarily imply differences.

[0019] It should be noted that, in this application, the terms "exemplary" or "for example" are used to indicate that something is being described as an example, illustration, or illustration. Any embodiment or design described as "exemplary" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments or design solutions. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0020] Example 1: like Figure 1 As shown, this embodiment provides a servo-based dynamic adjustment method for axial force based on foundation pit displacement feedback. This method achieves refined active control of the axial force of concrete supports by constructing a two-dimensional feedback mechanism of strength and displacement. The method mainly includes the following steps: S101. Obtain the real-time rebound strength of the concrete support. Based on the strength level achieved by the real-time rebound strength, perform graded initial loading to ensure close contact between the servo jack and the force transmission interface and establish the initial axial force.

[0021] Among them, real-time rebound strength refers to the surface hardness characterization value of concrete obtained directly on the construction site through non-destructive testing methods. It can reflect the actual bearing capacity of the concrete support at present, which is different from the laboratory compressive strength under standard curing conditions. The force transmission interface is the physical contact area between the end bearing surface of the concrete support and the lateral force-bearing surface of the retaining structure. It is the key physical channel for the axial force applied by the servo jack to be transmitted to the retaining structure. Its tightness directly determines the efficiency and uniformity of axial force transmission.

[0022] In this embodiment, the rebound value of the concrete support surface is periodically collected through the rebound test of the support beam, and converted into the corresponding strength level as the gating condition for loading permission. When the strength is detected to reach the preset first level, the servo jack is controlled to apply a preloaded axial force to eliminate the assembly gap at the force transmission interface. Subsequently, the target value of the axial force is gradually increased according to the strength growth until an initial axial force state matching the design working condition is established.

[0023] It should be noted that the initial loading increments and timing are not fixed, but dynamically determined based on the actual evolution of concrete material properties. This loading logic, which uses material strength as the trigger condition, fundamentally avoids the risk of localized crushing or plastic damage to concrete caused by early-age overloading.

[0024] As an example, after the concrete support is poured, rebound tests are conducted daily. When the measured rebound strength reaches the C15 level (the standard value of the cubic compressive strength of C15 concrete is about 15MPa), the servo system is activated to apply a preloaded axial force of 500kN to ensure that the jack is in close contact with the embedded steel plate. When the strength increases to the C20 level, the axial force is increased to 1000kN as the initial working axial force, thereby ensuring that the axial force is always within the safe bearing envelope of the concrete material during the axial force establishment process.

[0025] Based on the above steps, the timing of axial force application and the bearing capacity of concrete supports are synchronized, effectively solving the problem of structural damage or insufficient axial force caused by material strength dispersion in the traditional fixed-sequence loading mode, and ensuring the safety and effectiveness of the force transmission system.

[0026] S102. Obtain the interface separation displacement of the force transmission interface.

[0027] Among them, the interface separation displacement is the relative displacement difference between the concrete support end and the retaining structure. It is a key geometric parameter characterizing the degradation of the physical contact state of the force transmission interface. Its value directly reflects the degree of opening of the gap between the concrete support end and the retaining structure, and is a direct basis for judging whether the axial force transmission has failed.

[0028] In this embodiment of the application, high-precision displacement monitoring components are arranged on both sides of the force transmission interface. The lateral displacement data of the retaining structure and the axial displacement data of the concrete support end are obtained by the displacement acquisition module, and the two are synchronously differentially calculated to eliminate the interference of the overall deformation of the foundation pit on the local interface measurement and accurately extract the relative displacement component caused only by the interface separation.

[0029] As an example, vibrating wire displacement gauges were installed on the embedded steel plates on both sides of the servo jack. The sampling frequency was set to 1 time / hour. When the lateral displacement reading of the enclosure structure was 12.50 mm and the displacement reading of the concrete support end was 12.35 mm, the current interface separation displacement was calculated to be 0.15 mm. This value indicates that the force transmission interface is still in a tight fit.

[0030] Based on the above steps, accurate quantitative perception of the microscopic deformation state of the force transmission interface is achieved, providing high-confidence data input for subsequent axial force adjustment decisions and overcoming the technical blind spot that single axial force monitoring cannot identify the potential for interface detachment.

[0031] S103. Map the interface separation displacement to a preset multi-level displacement threshold range to determine the target displacement threshold range where the interface separation displacement is located.

[0032] Among them, the multi-level displacement threshold interval is a division rule that discretizes the continuous interface separation displacement value into several status labels with clear engineering semantics. Each interval corresponds to a specific interface health level, such as safe fit, slight separation, moderate separation or severe separation.

[0033] In this embodiment, multiple separation threshold boundaries are pre-set according to engineering design requirements and historical experience data to form a sequentially increasing displacement threshold interval sequence. After obtaining the real-time interface separation displacement, it is compared with the threshold boundaries at each level to quickly determine the target interval to which the current interface state belongs, thus completing the conversion from numerical signal to working condition semantics.

[0034] As an example, four displacement threshold ranges are set as [0,5)mm, [5,10)mm, [10,25)mm and ≥25mm respectively. When the interface separation displacement obtained by S102 is 8.788mm, it is determined by comparison that it falls into the second range [5,10)mm, which indicates that the current force transmission interface is in a slightly separated state.

[0035] Based on the above steps, standardized hierarchical identification of interface deformation states is achieved, enabling the control system to take targeted response measures according to different severity levels, avoiding control oscillations or response lags caused by single threshold judgments, and improving the system's decision-making intelligence level.

[0036] S104. Based on the target displacement threshold range, perform the corresponding axial force adjustment action, which includes at least one of positive compensation, pressure maintenance, or gradient unloading.

[0037] Among them, axial force adjustment is the mechanical response behavior of the servo system in response to a specific interface state. Positive compensation is used to actively make up for axial force loss when the interface is safe. Pressure holding is used to stabilize the current state and observe the trend when the interface is moderately separated. Gradient unloading is used to release stress in an orderly manner to prevent structural damage when the interface is severely separated.

[0038] In this embodiment of the application, a mapping relationship table between the target displacement threshold range and the axial force adjustment action is established. When the target range to which the interface state belongs is determined, the corresponding adjustment strategy is automatically called to generate control commands, which drive the servo hydraulic pump station to perform corresponding pressurization, pressure stabilization or pressure relief operations, so as to realize closed-loop feedback adjustment of the force transmission interface state.

[0039] Based on the above steps, the adaptive matching between the axial force adjustment strategy and the actual state of the force transmission interface is realized, enabling the servo system to maximize the active support efficiency while ensuring structural safety. This is significantly different from the extensive management method of blindly pressurizing or passively depressurizing under the traditional single axial force control mode.

[0040] Based on the above technical solution, this embodiment establishes the basic framework of the servo axial force dynamic adjustment method based on pit displacement feedback by constructing a dual main logic of strength-triggered loading and displacement-triggered adjustment. This ensures the synchronization between the axial force establishment process and the material performance evolution, and also achieves precise adaptation between axial force output and interface force transmission state during service. This provides a solid technical foundation for the development of subsequent advanced embodiments.

[0041] Example 2: In some embodiments, based on the strength level achieved by the real-time rebound strength, a graded initial loading is performed to ensure close contact between the servo jack and the force transmission interface and establish an initial axial force. This process is further refined into a step-by-step control logic synchronized with the evolution of material properties, such as... Figure 2 As shown, the specific steps include: S201. When the real-time rebound strength reaches the first strength level, apply a preloaded axial force to eliminate the gap at the force transmission interface.

[0042] Among them, the first strength grade is the minimum material performance threshold that allows the servo system to intervene in the work, and the preloaded axial force is the contact pressure used to overcome the mechanical assembly tolerance and the flatness deviation of the concrete surface. Its core purpose is to transform the force transmission interface from a physical "point contact" or "line contact" to a "surface contact" state that can uniformly transmit the load.

[0043] In this embodiment, by continuously monitoring the rebound strength value of the concrete support, once it is determined that it has reached the preset first strength level threshold, the preloading program is automatically triggered, and the servo jack is controlled to output a preset small tonnage axial force in a low-speed and stable mode. This axial force value is usually set to 10% to 20% of the maximum design axial force, which is sufficient to compact the micro-unevenness of the interface without causing structural deformation, thereby completing the initial construction of the force transmission channel as soon as the material has basic load-bearing capacity.

[0044] As an example, when the measured rebound strength of the concrete support reaches the C15 grade, the system automatically starts the preloading program, controls the servo jack to apply an axial pressure of 500kN, and maintains this pressure for 30 minutes. During this period, the interface compression is monitored by the displacement sensor. If the compression tends to stabilize and the oil pressure does not drop significantly, it is determined that the gap at the force transmission interface has been effectively eliminated, and the preloading stage is completed.

[0045] Based on the above steps, the force transmission relationship between the servo system and the concrete support was established at an early stage. By anchoring the loading starting point on the safety baseline of the material strength, the risk of early-age concrete damage caused by premature loading was fundamentally avoided, while providing reliable mechanical boundary conditions for subsequent high-precision axial force adjustment.

[0046] S202. When the real-time rebound strength reaches the higher second and third strength levels in sequence, the initial axial force is gradually increased according to the preset grade difference.

[0047] Among them, the second and third strength grades represent key nodes in the growth of concrete support bearing capacity. The preset grade difference is the incremental step size connecting each strength node with the corresponding axial force target value. Its value reflects the matching relationship between the improvement of material performance and the increase in load demand.

[0048] In this embodiment, a dynamic mapping model between strength grade and axial force target value is established. When the real-time rebound strength is detected to cross a higher grade threshold, the system automatically calculates or looks up the corresponding axial force increment based on the ratio of the current strength to the design axial force, and drives the servo jack to perform loading action according to the increment, forming an axial force loading trajectory that gradually increases with the increase of material strength, ensuring that the axial force level at each stage is within the safe bearing envelope of the current concrete material.

[0049] As an example, when the rebound strength of the concrete support increases from C15 to C20, the system increases the target axial force value from 500kN to 1000kN, with a increment of 500kN; when the strength further increases to C25, the target axial force value increases to 2000kN, with the increment expanding to 1000kN; when the strength reaches C30 and above, the target axial force value is adjusted to the range of 2500kN to 3000kN, with the increment narrowing to 500kN to 1000kN. The entire loading process exhibits a non-linear step characteristic of "small-large-small", which is highly consistent with the concrete strength growth rate and the structural stress requirements.

[0050] Based on the above steps, the axial force establishment process and the performance growth curve of concrete materials are precisely synchronized. By using a stepped loading path, the huge design axial force is decomposed into several safe increments that match the current bearing capacity of the material. This effectively prevents structural overload damage caused by one-time loading or mismatch in loading steps, and ensures the mechanical stability of the support system throughout its entire life cycle.

[0051] S203. After each loading stage, monitor the stress state of the force transmission system, and execute the next loading stage after confirming that there are no abnormalities.

[0052] Among them, the stress state of the force transmission system is a comprehensive indicator reflecting the effectiveness of axial force transmission and structural integrity. Confirming that there are no abnormalities is a necessary prerequisite for entering the next loading stage. In essence, it embeds a mandatory safety verification gate in the loading process.

[0053] In this embodiment, after each axial force loading action is completed, the system automatically enters the load observation period. During this period, hydraulic pump station oil pressure data, force transmission interface displacement data, and surface strain or crack observation data of the support structure are collected simultaneously. Only when the oil pressure remains stable within a preset time, the interface displacement converges, and no new cracks or abnormal deformations appear, it is determined that the current loading has been safely accepted by the structure, and the next loading permission is unlocked. Otherwise, the system will maintain the current state or trigger the degradation protection mechanism.

[0054] It should be noted that confirming the stress state is a multi-dimensional cross-verification process. The qualification of a single indicator is not enough to prove the overall safety. For example, stable oil pressure only means that the hydraulic system is normal, but if the interface displacement continues to diverge, it may mean that the concrete is undergoing plastic flow or the embedded parts are slipping. In this case, even if the oil pressure meets the standard, the loading must be stopped. This judgment logic of multi-source information fusion significantly improves the reliability and safety of state confirmation.

[0055] As an example, after loading a 1000kN axial force, the system enters a 2-hour load observation period, during which oil pressure and displacement data are recorded every 5 minutes. If the oil pressure fluctuation is less than 2% and the interface displacement change is less than 0.1mm within 4 consecutive sampling cycles, and the on-site inspectors report no new cracks on the surface of the support beam, the system automatically determines that the stress state is normal and allows the next stage of loading to the 2000kN target to be executed. Conversely, if an abnormal drop in oil pressure or a continuous increase in displacement is found during the observation period, the system locks the current axial force and generates an anomaly report, which can only continue after manual investigation and handling are completed.

[0056] Based on the above steps, real-time linkage between the loading process and the structural safety status was achieved. By setting a mandatory health check after each loading stage, potential risk transmission paths caused by material defects, construction deviations, or environmental disturbances were effectively identified and blocked, ensuring the controllability and safety of the entire initial loading process and avoiding sudden structural failures caused by the accumulation of hidden dangers under the traditional open-loop loading mode.

[0057] Example 3: In some embodiments, obtaining the interface separation displacement of the force transmission interface includes: acquiring lateral displacement data of the retaining structure and axial displacement data of the concrete support end by means of displacement monitoring components arranged on both sides of the force transmission interface; calculating the interface separation displacement based on the difference between the lateral displacement data and the axial displacement data; or, directly acquiring the gap width of the force transmission interface as the interface separation displacement by means of a crack ranging sensor arranged at the force transmission interface.

[0058] Among them, the indirect calculation method inverts the relative deformation by decoupling the absolute motion of the enclosure structure and the support end, which is suitable for working conditions where conventional automated monitoring systems have been deployed; the direct measurement method directly senses the geometric opening and closing of the physical gap by installing special sensing elements across the gap, which can eliminate the interference of the overall rigid body displacement of the structure and more purely characterize the degree of degradation of the contact state of the force transmission interface.

[0059] In this embodiment, for the indirect calculation method, a first measuring point is set at a position near the force transmission interface of the retaining structure to collect lateral displacement data, and a second measuring point is set at a position close to the force transmission interface at the end of the concrete support to collect axial displacement data. The data acquisition modules of the two measuring points keep their clocks synchronized. The system performs vector difference calculation on the lateral displacement data and axial displacement data at the same time to eliminate common-mode interference caused by the overall settlement or horizontal drift of the foundation pit, thereby extracting the true interface separation component. For the direct measurement method, a high-precision crack ranging sensor is installed across the force transmission interface. Its fixed end and movable end are anchored to the end face of the retaining structure and the concrete support, respectively. The sensor has a built-in temperature compensation module to eliminate the influence of ambient temperature changes on the reading accuracy, and continuously outputs the crack width value at a sampling rate of not less than a preset frequency. This value is directly identified as the interface separation displacement.

[0060] It should be noted that the two acquisition methods mentioned above are not mutually exclusive. In practical engineering applications, they can be flexibly configured according to the on-site monitoring conditions. For example, in scenarios where monitoring resources are limited, the indirect calculation method can be used first to reuse existing components and reduce costs. At critical nodes where the sensitivity to interface status is extremely high, the direct measurement method can be used to improve data confidence. The two methods can even be deployed in parallel, using the direct measurement value as a benchmark to calibrate the indirect calculation model in real time, thereby building a multi-redundant data verification system to prevent control decision errors caused by the failure or drift of a single sensor.

[0061] Based on the above steps, a variety of methods for obtaining interface separation displacement have been achieved. This not only ensures data availability under different construction environments and cost constraints, but also improves the accuracy and anti-interference ability of local deformation characterization through direct measurement. It effectively prevents risks that can be easily avoided due to a single technical means, and provides a solid and reliable data foundation for subsequent multi-level threshold mapping.

[0062] Example 4: In some embodiments, based on the two-dimensional feedback regulation framework determined in Example 1, the threshold mapping logic, differentiated regulation strategy, execution closed-loop mechanism, and key parameter boundaries are further specified to construct a complete and refined control link, such as... Figure 3 As shown, it specifically includes: S301. Obtain multiple preset separation thresholds; compare the interface separation displacement with the multiple separation thresholds; based on the comparison results, determine the displacement threshold interval into which the interface separation displacement falls as the target displacement threshold interval.

[0063] Among them, multiple separation thresholds divide the displacement range into multiple displacement threshold intervals that increase sequentially. The separation thresholds are critical values ​​that are pre-calibrated based on engineering experience and structural mechanical characteristics. Their function is to transform the analog quantity of continuously changing interface separation displacement into a discrete state label with clear engineering semantics, so that the control system can identify different damage levels from intact to failed. The target displacement threshold interval characterizes the severity of the separation of the force transmission interface.

[0064] In this embodiment, five key separation threshold nodes are set: 5mm, 10mm, 20mm, 25mm, and an implicit 0mm starting point. This constructs five sequentially increasing displacement threshold intervals. The interface separation displacement data received by the system in real time is automatically substituted into this interval sequence for comparison and calculation. Once the value falls into a specific interval, it is marked as the corresponding target displacement threshold interval. This interval is not only a numerical range, but also directly maps the current physical contact state and health level of the force transmission interface, providing standardized decision input for subsequent differentiated adjustment.

[0065] As an example, in a deep foundation pit project, the system divides the displacement threshold range into five levels: [0,5)mm, [5,10)mm, [10,20)mm, [20,25)mm, and ≥25mm. When the measured interface separation displacement is 8.788mm, it is determined by comparison to fall into the second range [5,10)mm. The system then marks it as a "slightly detached" state, thereby triggering an adjustment strategy that matches this state.

[0066] Based on the above steps, standardized hierarchical identification of interface deformation states is achieved, transforming complex physical deformation problems into computable logical state problems, which significantly improves the perception granularity and decision-making accuracy of the control system regarding the health status of the force transmission interface.

[0067] S302. Based on the target displacement threshold range, perform the corresponding axial force adjustment action, including: when the target displacement threshold range is the first range, perform positive compensation; the first range indicates that the force transmission interface is in a safe fit state; when the target displacement threshold range is the second range, reduce the adjustment increment of positive compensation; the second range indicates that the force transmission interface is in a slightly disengaged state; when the target displacement threshold range is the third range, perform pressure holding maintenance; the third range indicates that the force transmission interface is in a moderately disengaged state; when the target displacement threshold range is the fourth range, perform gradient unloading; the fourth range indicates that the force transmission interface is in a severely disengaged state.

[0068] Among them, the four adjustment actions correspond to four different mechanical response requirements of the force transmission interface. Positive compensation aims to actively make up for axial force loss to maintain support effectiveness, reduction compensation is intended to prevent excessive compression from aggravating interface damage, pressure holding is used to stabilize the working condition under uncertain conditions to observe trends, and gradient unloading is to release stress in an orderly manner to avoid structural damage when the interface fails.

[0069] In this embodiment, for the first interval, i.e., the safe fit state, the system increases the axial force by a preset step size to offset the prestress loss caused by concrete shrinkage and creep, fully utilizing the active support efficiency of the servo system; for the second interval, i.e., the slight separation state, the system automatically reduces the loading increment or switches to a low-speed fine-tuning mode to avoid localized stress concentration at the interface due to blind pressure, which could induce a larger-scale separation; for the third interval, i.e., the moderate separation state, the system locks the current axial force value and enters a pressure-holding observation period, suspending all active adjustment actions until the interface deformation trend stabilizes before making a decision, preventing secondary risks caused by misoperation during the rapid deformation development period; for the fourth interval, i.e., the severe separation state, the system immediately starts a gradient unloading program, reducing the target axial force value in stages, so that the internal force of the support is gradually transferred to the retaining structure or other support components, avoiding uncontrolled redistribution of internal forces due to instantaneous unloading.

[0070] It should be noted that this graded response mechanism embodies the control concept of applying force on demand and prioritizing safety. Its physical mechanism is based on the recognition that there are essential differences in the bearing capacity and transmission efficiency of the force transmission interface under different degrees of damage. Applying pressure is only effective when the interface is intact, while continuing to apply pressure when the interface is damaged may become a cause of damage. Therefore, the force output strategy must be dynamically adjusted according to the interface state.

[0071] As an example, when the interface separation displacement is less than 5mm, the system determines that it is a safe fit and increases the axial force by 500kN in each cycle to compensate for the loss; when the displacement is between 5mm and 10mm, the system adjusts the single loading increment to 150kN and extends the loading interval; when the displacement is between 10mm and 20mm, the system maintains the current axial force and monitors continuously for 2 hours; when the displacement exceeds 25mm, the system unloads in increments of 500kN until the displacement falls back to the safe range or reaches the minimum safe axial force limit.

[0072] Based on the above steps, an adaptive and precise match between the axial force adjustment strategy and the actual state of the force transmission interface is achieved, enabling the servo system to maximize its active support performance while ensuring structural safety. This effectively solves the problem of extensive management caused by blindly applying pressure or passively releasing pressure under the traditional single axial force control mode.

[0073] S303. Based on the adjustment strategy corresponding to the target displacement threshold range, calculate the axial force adjustment increment; generate a control command containing the axial force adjustment increment and a preset loading or unloading rate; output the control command to the servo hydraulic pump station to drive the servo jack to perform the action; obtain the axial force feedback value of the servo jack in real time, and trigger the pressure stabilization self-locking when the axial force feedback value reaches the target axial force value.

[0074] Among them, the axial force adjustment increment is the target change amount of this adjustment action, the preset loading or unloading rate is a safety parameter that limits the pressure change gradient of the hydraulic system, and the pressure stabilization self-locking is a closed-loop confirmation mechanism that ensures the final adjustment value is accurately maintained.

[0075] In this embodiment, the system first calculates the required increase or decrease in axial force based on the strategy corresponding to the current axial force value and the target range. Then, it packages the incremental value with a preset safety rate parameter to generate a standard control command, which is sent to the controller of the servo hydraulic pump station via a communication bus. After parsing the command, the pump station controller drives the proportional valve or servo motor to adjust the oil pressure at a specified rate. At the same time, during the execution process, the real-time axial force feedback value of the jack's built-in sensor is collected at a millisecond frequency. Once the deviation between the feedback value and the target value is detected to enter the allowable tolerance zone, the hydraulic lock-up circuit is immediately triggered and the power output is stopped, completing a complete adjustment closed loop.

[0076] It should be noted that the introduction of rate control and pressure stabilization self-locking mechanism is the key to ensuring the smooth operation and adjustment accuracy of the hydraulic system. Without rate limit, rapid pressurization may cause hydraulic shock to damage the seals or cause reading distortion. Without self-locking confirmation, the system cannot determine whether the adjustment is truly in place, which may cause the axial force to deviate from the target value for a long time and lose its control significance.

[0077] As an example, when the system decides to increase the axial force by 500kN, the generated control command includes an increment of +500kN and a loading rate of 100kN / min. After receiving the command, the pump station steadily increases the pressure at this rate. When the real-time axial force feedback value reaches the target value within ±20kN, the solenoid valve automatically closes and triggers mechanical self-locking. The entire loading process takes 5 minutes and there is no pressure overshoot.

[0078] Based on the above steps, a complete closed-loop control from decision-making to execution is achieved, ensuring that every axial force adjustment action can be smoothly and accurately implemented and maintained, effectively preventing control deviations and equipment damage caused by the dynamic characteristics of the hydraulic system.

[0079] S304. Constrain the measurement accuracy of the interface separation displacement and the unloading amplitude of the gradient unloading.

[0080] Among them, measurement accuracy is the technical prerequisite for ensuring the observability of minute interface changes, while unloading range is the safety boundary to prevent structural instability caused by excessive unloading under extreme working conditions.

[0081] In this embodiment, a high-precision crack ranging sensor or differential displacement meter with a resolution of 0.01 mm is selected as the data acquisition source to ensure that the initial evolution signal of the force transmission interface from close contact to slight separation can be captured, providing data support for early warning and fine adjustment. At the same time, a safety limit for unloading is set in the control algorithm. When the system determines that the interface separation displacement has exceeded 25 mm and entered the severe separation range, the unloading amplitude of the gradient unloading is set to 500 kN.

[0082] Based on the above steps, the dual protection of high-precision perception and safety boundary constraints not only improves the system's sensitivity to normal small deformations, but also ensures the safety of emergency response under abnormal large deformation conditions, significantly enhancing the robustness and reliability of the servo system in complex engineering environments.

[0083] Based on the above technical solutions, this embodiment organically integrates multi-level threshold mapping, differentiated adjustment strategies, execution closed-loop mechanisms, and key parameter boundaries to construct a complete and refined control link from state perception to decision execution and then to safety assurance. It achieves adaptive and precise matching between axial force adjustment and force transmission interface state, which not only ensures the active support efficiency under normal conditions but also ensures structural safety under extreme working conditions, significantly improving the intelligence level and engineering applicability of the servo system.

[0084] Example 5: In some embodiments, to address potential conflicts between maintaining the local state of the force transmission interface and controlling the overall stability of the foundation pit, this application further constructs a joint adjustment mechanism for lateral displacement deformation in addition to the main control link described in embodiments 1 to 4. This mechanism includes: acquiring the lateral displacement deformation of the retaining structure; determining whether the lateral displacement deformation exceeds a preset lateral displacement alarm threshold; and if it exceeds the lateral displacement alarm threshold, triggering the joint adjustment mechanism to dynamically correct the axial force adjustment action determined based on the interface separation displacement.

[0085] Among them, lateral displacement deformation is a macroscopic geometric indicator characterizing the overall stability of the foundation pit retaining structure. It is usually collected by inclinometers and inclinometers embedded in the retaining wall, or provided periodically by a third-party monitoring unit. It reflects the comprehensive response of the retaining system under soil pressure. The lateral displacement alarm threshold is a critical safety boundary set according to the foundation pit safety level and design specifications. Once this boundary is exceeded, it means that the foundation pit faces the risk of overall instability. The joint adjustment mechanism is a high-priority safety intervention strategy. Its essence is to temporarily suspend the conventional adjustment logic based on the interface state under specific emergency conditions, and instead forcibly correct the axial force output with the primary goal of ensuring overall stability.

[0086] In this embodiment, the system accesses or periodically reads deep horizontal displacement monitoring data of the enclosure structure through a data interface and compares it with a preset lateral displacement alarm threshold. When the lateral displacement deformation exceeds the limit, a joint adjustment trigger signal is immediately generated. This signal has a higher execution priority than conventional interface displacement adjustment commands and can directly intervene and modify the axial force adjustment action parameters that are currently being executed or about to be executed. Thus, in the event of a conflict where the interface state logic believes that the status quo should be maintained but the overall safety logic requires "immediate action", the system response always conforms to the higher-level safety requirements.

[0087] As an example, the system receives tilt measurement data submitted by a third-party monitoring unit every day. When it detects that the daily lateral displacement of the retaining structure corresponding to a certain support point is greater than 2mm or the cumulative deformation reaches 70% of the design alarm value, it determines that the lateral displacement deformation exceeds the preset lateral displacement alarm threshold, and then triggers the joint adjustment mechanism to send a correction command to the servo hydraulic pump station, overriding the original control logic based on the interface separation displacement.

[0088] Based on the above steps, the coordination between local component status maintenance and overall structural safety management is realized, solving the problem that traditional single-dimensional control cannot take into account multiple safety objectives, and ensuring that the servo system can always make the correct decisions that meet the highest safety interests in the complex and ever-changing foundation pit engineering environment.

[0089] Furthermore, the process of dynamically correcting the axial force adjustment action determined based on the interface separation displacement specifically includes: when the interface separation displacement is in the range corresponding to the pressure holding, and the lateral deformation exceeds the lateral displacement alarm threshold, the target value of the pressure holding axial force is dynamically increased according to the preset lateral displacement compensation gradient; when the lateral deformation is detected to fall back to the safe range, the target value of the pressure holding axial force is restored to the initial pressure holding value.

[0090] The pressure holding interval is the third interval defined in Example 4 (e.g., 10mm to 20mm). Within this interval, conventional logic prohibits active pressure application to prevent exacerbating interface separation. The lateral displacement compensation gradient is the axial force increment step size set to balance the overall stability requirements and the interface bearing capacity. Its value must be sufficient to generate support resistance to curb overall deformation, while avoiding local crushing of the concrete support end due to excessive single loading. The initial pressure holding value is the benchmark axial force value determined by the system based on the interface state before triggering joint adjustment, serving as the anchor point for returning to normal control after the danger is eliminated.

[0091] In this embodiment, when the joint adjustment mechanism is activated and it is confirmed that the current interface is in the pressure holding range, the system does not directly increase the axial force to the design maximum value. Instead, it gradually increases the target value of the pressure holding axial force according to the preset lateral displacement compensation gradient (e.g., 250kN per level). After each level of increase, a short observation window is set to evaluate the deformation suppression effect and interface response. If the lateral displacement deformation falls back to the safe range after adjustment, the system automatically resets the target value of the pressure holding axial force to the initial pressure holding value before triggering the joint adjustment, so that the control logic smoothly returns to the normal adjustment track based on the interface state. This minimizes the additional damage to the force transmission interface while completing the emergency rescue task.

[0092] As an example, during the construction of a deep foundation pit project, the system monitored an interface separation displacement of 15mm at a certain support point (within the pressure maintenance range). At the same time, the monitoring data showed that the daily lateral displacement of the retaining structure at this location reached 2.5mm (exceeding the 2mm alarm threshold). The system then triggered a joint adjustment mechanism, increasing the target value of the pressure maintenance axial force from the current 1500kN to 1750kN in increments of 250kN. After 2 hours of observation, the lateral displacement rate slowed down significantly and fell back to 1.8mm (within the safe range) the next day. The system then automatically restored the target value of the pressure maintenance axial force to 1500kN and continued to execute the original pressure maintenance strategy. The entire process did not cause further deterioration of the interface separation.

[0093] Based on the above steps, refined protection of the force transmission interface state is achieved under the premise of ensuring the overall stability of the foundation pit. The elastic correction strategy effectively avoids secondary risks that may be caused by mechanical execution of a single rule, and significantly improves the robustness and engineering applicability of the servo system under extreme contradictory working conditions.

[0094] Example 6: like Figure 4 As shown, this embodiment provides a servo axial force dynamic adjustment system based on foundation pit displacement feedback. This system achieves automated execution of the aforementioned method through a modular architecture, providing a hardware platform for the intelligent control of the deep foundation pit concrete support servo system. The system includes an initial loading module 401, a displacement acquisition module 402, an interval mapping module 403, and an adjustment control module 404.

[0095] The initial loading module 401 is used to acquire the real-time rebound strength of the concrete support. Based on the strength level achieved by the real-time rebound strength, it performs graded initial loading to ensure close contact between the servo jack and the force transmission interface and establish the initial axial force. The force transmission interface is the physical contact area between the end bearing surface of the concrete support and the lateral force-bearing surface of the retaining structure. Specifically, the initial loading module 401 can be constructed in hardware by an industrial control computer or embedded controller in conjunction with a rebound strength acquisition interface and a hydraulic drive circuit. It internally stores a strength-axial force mapping strategy table. When it receives the strength characterization value input from an external rebound detection device, it automatically matches the corresponding pre-loading or graded loading target value and sends a start command to the hydraulic pump station through analog output or bus communication. At the same time, it reads the jack stroke and pressure feedback in real time to determine the close contact state, thereby solidifying the graded loading logic in Embodiments 1 and 2 into an executable machine instruction sequence, ensuring that the axial force establishment process is strictly controlled by the material performance evolution rhythm.

[0096] The displacement acquisition module 402 is used to acquire the interface separation displacement of the force transmission interface; the interface separation displacement is the relative displacement difference between the concrete support end and the retaining structure. In this embodiment, the displacement acquisition module 402 integrates a multi-channel data acquisition unit and a signal conditioning circuit, which can be compatible with the access of various types of sensors such as vibrating wire, inductive, or laser sensors. For the indirect calculation method scenario, the module has a built-in synchronous differential algorithm to perform millisecond-level alignment and vector operation on the two signals of the lateral displacement of the retaining structure and the axial displacement of the support end, eliminating common-mode interference. For the direct measurement method scenario, the module directly parses the digital signal of the crack ranging sensor and performs temperature compensation correction. Regardless of the sensing path used, the module ultimately outputs a standardized interface separation displacement value for downstream modules to call, realizing the hardware-level adaptation and fusion of the two displacement acquisition methods in Embodiment 3.

[0097] The interval mapping module 403 is used to map the interface separation displacement to a preset multi-level displacement threshold interval, thereby determining the target displacement threshold interval in which the interface separation displacement is located. It should be noted that the interval mapping module 403 is not a simple numerical comparator, but a configurable decision unit that carries the multi-level threshold division logic in Embodiment 4. Its internal registers or storage areas are pre-set with multiple separation threshold boundary parameters. These parameters can be calibrated and dynamically adjusted on-site through a human-machine interface or a remote configuration interface to adapt to the needs of different foundation pit safety levels and geological conditions. When it receives the real-time displacement output by the displacement acquisition module 402, the module quickly determines the target interval in which it is located through a hardware comparator array or a software lookup table method, and transmits the status code representing "safe fit", "slight separation", "moderate separation" or "severe separation" to the adjustment and control module 404, thus completing the real-time conversion from continuous physical quantity to discrete control semantics.

[0098] The adjustment control module 404 is used to execute corresponding axial force adjustment actions based on the target displacement threshold range. The axial force adjustment actions include at least one of positive compensation, pressure holding, or gradient unloading. As an example, the adjustment control module 404 is implemented by a high-performance PLC or a dedicated motion controller. It internally encapsulates a PID adjustment algorithm, a rate limiting function, and safety interlock logic that correspond one-to-one with the four target ranges. When it receives a status code from the range mapping module 403, it automatically calls the corresponding control strategy to generate a composite control command containing the axial force increment, unloading amplitude, and loading / unloading rate. This command is then sent to the execution unit of the servo hydraulic pump station via an industrial Ethernet or CAN bus. Simultaneously, it continuously collects the real-time axial force feedback value of the jack during execution. Once the feedback value is detected to have reached the target value and stabilized within the allowable tolerance zone, a pressure stabilization self-locking signal is immediately triggered and the power output is shut off. This completely replicates the entire process of adjustment actions from strategy matching and command generation to closed-loop confirmation in Example 4, ensuring that each axial force adjustment is implemented accurately and smoothly.

[0099] Based on the above technical solution, this embodiment materializes each key step in the method process into a dedicated functional module, and clarifies the hardware implementation, input / output interfaces and collaborative working mechanism of each module. This not only ensures the consistency of the protection scope of system independence and method independence, but also constructs an intelligent upgrade carrier with a fully automated closed loop. This enables the servo system to autonomously complete the entire control link from strength perception, displacement monitoring, state judgment to axial force adjustment without frequent manual intervention, significantly improving the precision level and safety response efficiency of deep foundation pit support construction.

[0100] Although this application has been described herein in conjunction with various embodiments, those skilled in the art, by reviewing the accompanying drawings, disclosure, and appended claims, will understand and implement other variations of the disclosed embodiments in carrying out the claimed application. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude multiple instances. A single processor or other unit can implement several functions listed in the claims. While different dependent claims may recite certain measures, this does not mean that these measures cannot be combined to produce good results.

[0101] Although this application has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made thereto without departing from the spirit and scope of this application. Accordingly, this specification and drawings are merely exemplary illustrations of this application as defined by the appended claims, and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from the spirit and scope of this application. Thus, if such modifications and modifications of this application fall within the scope of the claims of this application and their equivalents, this application is also intended to include such modifications and modifications.

Claims

1. A servo-driven dynamic adjustment method for axial force based on foundation pit displacement feedback, characterized in that, include The real-time rebound strength of the concrete support is obtained. Based on the strength level reached by the real-time rebound strength, a graded initial loading is performed to make the servo jack closely adhere to the force transmission interface and establish an initial axial force. The force transmission interface is the physical contact area between the end bearing surface of the concrete support and the lateral force-bearing surface of the enclosure structure. Obtain the interface separation displacement of the force transmission interface; The interface separation displacement is the relative displacement difference between the concrete support end and the enclosure structure. The interface separation displacement is mapped to a preset multi-level displacement threshold range to determine the target displacement threshold range in which the interface separation displacement is located. Based on the target displacement threshold range, a corresponding axial force adjustment action is performed, which includes at least one of positive compensation, pressure maintenance, or gradient unloading.

2. The method according to claim 1, characterized in that, Based on the strength level achieved by the real-time rebound strength, the step of performing graded initial loading to ensure close contact between the servo jack and the force transmission interface and establish an initial axial force includes: When the real-time rebound strength reaches the first strength level, a preloaded axial force is applied to eliminate the gap at the force transmission interface. When the real-time rebound strength successively reaches a higher second strength level and a higher third strength level, the initial axial force is gradually increased according to the preset grade difference; After each loading stage, the stress state of the force transmission system is monitored, and the next loading stage is executed only after confirming that there are no abnormalities.

3. The method according to claim 1, characterized in that, The step of obtaining the interface separation displacement of the force transmission interface includes: By using displacement monitoring components arranged on both sides of the force transmission interface, the lateral displacement data of the enclosure structure and the axial displacement data of the concrete support end are obtained respectively. The interface separation displacement is calculated based on the difference between the lateral displacement data and the axial displacement data; or, The crack width of the force transmission interface is directly collected as the interface separation displacement by means of a crack ranging sensor arranged at the force transmission interface.

4. The method according to claim 1, characterized in that, The step of mapping the interface separation displacement to a preset multi-level displacement threshold range and determining the target displacement threshold range in which the interface separation displacement is located includes: Obtain multiple preset separation thresholds; the multiple separation thresholds divide the displacement range into multiple displacement threshold intervals that increase sequentially; The interface separation displacement is compared with the plurality of separation thresholds; Based on the comparison results, the displacement threshold range into which the interface separation displacement falls is determined as the target displacement threshold range; the target displacement threshold range characterizes the severity of the separation of the force transmission interface.

5. The method according to claim 4, characterized in that, The step of performing the corresponding axial force adjustment action based on the target displacement threshold range includes: When the target displacement threshold interval is the first interval, the positive compensation is performed; the first interval indicates that the force transmission interface is in a safe fit state; When the target displacement threshold range is the second range, the adjustment increment of the positive compensation is reduced; the second range indicates that the force transmission interface is in a slightly disengaged state. When the target displacement threshold range is the third range, the pressure holding is performed; the third range indicates that the force transmission interface is in a moderately disengaged state. When the target displacement threshold interval is the fourth interval, the gradient unloading is performed; the fourth interval indicates that the force transmission interface is in a severely detached state.

6. The method according to claim 5, characterized in that, The execution of the corresponding axial force adjustment action includes: Based on the adjustment strategy corresponding to the target displacement threshold range, calculate the axial force adjustment increment; Generate control commands that include the axial force adjustment increment and the preset loading or unloading rate; The control command is output to the servo hydraulic pump station to drive the servo jack to perform the action; The axial force feedback value of the servo jack is acquired in real time. When the axial force feedback value reaches the target axial force value, the voltage stabilization self-locking is triggered.

7. The method according to claim 1, characterized in that, The method further includes: Obtain the lateral displacement deformation of the enclosure structure; Determine whether the lateral displacement deformation exceeds a preset lateral displacement alarm threshold; If the lateral displacement alarm threshold is exceeded, a joint adjustment mechanism is triggered to dynamically correct the axial force adjustment action determined based on the interface separation displacement.

8. The method according to claim 7, characterized in that, The dynamic correction of the axial force adjustment action determined based on the interface separation displacement includes: When the interface separation displacement is within the range corresponding to the pressure holding, and the lateral deformation exceeds the lateral displacement alarm threshold, the target value of the pressure holding axial force is dynamically increased according to the preset lateral displacement compensation gradient. When the lateral deformation is detected to have fallen back to a safe range, the target value of the pressure-holding axial force is restored to the initial pressure-holding value.

9. The method according to claim 1, characterized in that, The measurement accuracy of the interface separation displacement is not less than 0.01 mm. When the interface separation displacement exceeds 25 mm, the unloading amplitude of the gradient unloading is 500 kN.

10. A servo-driven axial force dynamic adjustment system based on foundation pit displacement feedback, characterized in that, The system includes: The initial loading module is used to obtain the real-time rebound strength of the concrete support. Based on the strength level reached by the real-time rebound strength, it performs graded initial loading to make the servo jack closely adhere to the force transmission interface and establish the initial axial force. The force transmission interface is the physical contact area between the end bearing surface of the concrete support and the lateral force-bearing surface of the retaining structure. The displacement acquisition module is used to acquire the interface separation displacement of the force transmission interface; the interface separation displacement is the relative displacement difference between the concrete support end and the retaining structure. The interval mapping module is used to map the interface separation displacement to a preset multi-level displacement threshold interval, and to determine the target displacement threshold interval in which the interface separation displacement is located. The adjustment control module is used to perform corresponding axial force adjustment actions based on the target displacement threshold range, wherein the axial force adjustment actions include at least one of positive compensation, pressure maintenance, or gradient unloading.

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