A deep foundation pit construction parameter self-adaptive regulation and control method based on support axial force and enclosure wall deformation joint inversion

Abstract

This invention discloses an adaptive control method for deep foundation pit construction parameters based on the joint inversion of support axial force and retaining wall deformation, relating to the field of construction technology, and includes the following steps: S1, determination of stable monitoring interval: receiving axial force monitoring data of each support and deformation monitoring data of each monitoring point of the retaining wall in the current excavation stage; determining a stable monitoring interval in which both the support axial force and the retaining wall deformation are in a stable state according to the rate of change of continuous monitoring data; outputting the benchmark support axial force, benchmark retaining wall deformation and corresponding change trend in the stable monitoring interval. Before the construction of the next excavation unit, this invention applies a reversible axial force disturbance to the target support to restore the benchmark axial force, and jointly corrects the current construction stage model based on the synchronous incremental response of the target support, adjacent supports and the retaining wall, and uses the corrected model to determine the construction parameters of the next excavation unit.

Description

Technical Field

[0001] This invention relates to the field of construction technology, specifically to an adaptive control method for deep foundation pit construction parameters based on the joint inversion of support axial force and retaining wall deformation. Background Technology

[0002] Deep foundation pit construction typically employs a layered, segmented excavation method with gradual erection of supports. During construction, the retaining wall deforms under the influence of external soil pressure, internal unloading, and support constraints. Each support layer accordingly bears and transmits the load of the retaining system. To monitor the current stress state of the foundation pit, axial force monitoring points for supports and deformation monitoring points for the retaining wall are usually installed. Combined with a foundation pit construction stage model, the deformation of the retaining wall and the axial force of the supports under subsequent excavation conditions are predicted. Based on this, the excavation layer thickness, excavation segment length, and support follow-up time limit for the next excavation unit are determined.

[0003] In deep foundation pits where excavation is carried out in sections, supports are gradually formed, and the forces in each construction area influence each other, axial force redistribution may occur between adjacent supports. The retaining wall may also be simultaneously affected by soil unloading, support constraints, and slow deformation trends, leading to similar monitoring results for support axial force and retaining wall deformation under different actual stress states. Existing technologies, when modifying construction stage models based solely on static monitoring data obtained during normal construction, struggle to distinguish whether monitoring changes are caused by actual changes in the retaining wall's flexibility or by changes in axial force transmission between supports. This can result in a modified model that, while able to fit existing monitoring data, fails to accurately reflect the incremental stress relationships of the current construction stage, thereby reducing the reliability of the predicted construction parameters for the next excavation unit. Summary of the Invention

[0004] The purpose of this invention is to provide an adaptive control method for deep foundation pit construction parameters based on the joint inversion of support axial force and retaining wall deformation, so as to solve the problems mentioned in the background art.

[0005] To address the aforementioned technical problems, this invention provides the following technical solution: an adaptive control method for deep foundation pit construction parameters based on the joint inversion of support axial force and retaining wall deformation, comprising the following steps: S1, Determination of Stable Monitoring Interval: Receive axial force monitoring data of each support and deformation monitoring data of each monitoring point of the retaining wall during the current excavation stage; determine the stable monitoring interval where both the axial force of the support and the deformation of the retaining wall are in a stable state based on the rate of change of the continuous monitoring data; output the reference axial force of the support, the reference deformation of the retaining wall, and the corresponding trend of change within the stable monitoring interval; S2, Reversible axial force disturbance application: Based on the position of the next excavation unit, determine the target support from the supports already in operation; control the target support to sequentially complete loading, recovery, unloading and recovery again, so that the axial force of the target support after the disturbance ends returns to the reference support axial force before the disturbance; output the actual axial force disturbance sequence of the target support and the time range of each disturbance stage; S3, Incremental response data extraction: During the application of the actual axial force disturbance sequence, monitoring data of each monitoring point of the target support, adjacent support and retaining wall are collected simultaneously; according to the change trend output in step S1, the background change when no axial force disturbance is applied is removed from the monitoring data; the target support axial force increment, adjacent support axial force increment and retaining wall deformation increment corresponding to each disturbance stage are output; S4, Current Stage Response Relationship Inversion: Receive the initial stage model corresponding to the current construction state of the deep foundation pit, and apply the same axial force disturbance sequence as in step S2 to the initial stage model; determine the retaining wall deformation response correction coefficient and the support axial force transmission correction coefficient based on the incremental response data output in step S3 and the simulated incremental response output by the initial stage model; correct the initial stage model using the retaining wall deformation response correction coefficient and the support axial force transmission correction coefficient, and output the current stage model; S5, Determining construction parameters: Input multiple candidate construction parameter groups into the current stage model respectively. Each candidate construction parameter group includes the excavation layer thickness, excavation segment length, and support follow-up time limit; predict the retaining wall deformation and support axial force corresponding to each candidate construction parameter group, and eliminate candidate construction parameter groups whose prediction results exceed the remaining deformation allowance or the remaining support bearing capacity; determine the construction parameters of the next excavation unit based on the retained candidate construction parameter groups and output the construction instructions.

[0006] According to the above technical solution, S1 includes: S1-1, receive axial force monitoring data of each support and deformation monitoring data of each monitoring point of the retaining wall at the same sampling time, and establish a continuous sliding interval according to the preset time length; S1-2, calculate the unit time change of the support axial force and the unit time change of the retaining wall deformation in each continuous sliding interval respectively; S1-3, when the unit time change of the axial force of all supports is less than the corresponding axial force stability threshold, and the unit time change of the deformation of all retaining walls is less than the corresponding deformation stability threshold, the continuous sliding interval is determined as the stability monitoring interval. S1-4, perform linear fitting on the axial force monitoring data of each support and the deformation monitoring data of each monitoring point within the stable monitoring interval, determine the data at the starting time of the fitting as the reference support axial force and the reference retaining wall deformation, and determine the fitting slope as the corresponding trend of change.

[0007] According to the above technical solution, step S2 includes: S2-1, the adjustable support that corresponds to the next excavation unit in the horizontal direction and is closest to the bottom of the next excavation unit in the vertical direction is determined as the target support; S2-2, Determine the axial force disturbance amount based on the reference support axial force of the target support, the upper limit of the design axial force, and the preset disturbance ratio, so that the axial force of the target support after the load increase is lower than the upper limit of the design axial force; S2-3, control the target support to increase the axial force disturbance from the reference support axial force, restore it to the reference support axial force, then decrease the axial force disturbance from the reference support axial force, and finally restore it to the reference support axial force; S2-4. During any disturbance phase, when the deformation increment of the retaining wall reaches the detection deformation limit, or the axial force of any support reaches the corresponding detection axial force limit, the current disturbance phase is terminated and the target support is controlled to return to the reference support axial force.

[0008] According to the above technical solution, step S3 includes: S3-1, Based on the reference support axial force, reference retaining wall deformation and change trend determined in step S1, calculate the background value of support axial force and the background value of retaining wall deformation at each sampling time during the axial force disturbance period; S3-2, subtract the corresponding background value of the support axial force from the actual support axial force at each sampling time to obtain the support axial force increment, and subtract the corresponding background value of the enclosure wall deformation from the actual enclosure wall deformation at each sampling time to obtain the enclosure wall deformation increment. S3-3, extract the median of the support axial force increment and the median of the retaining wall deformation increment within the preset sampling interval at the end of the load increase and load decrease stages, respectively, as the incremental response data for the corresponding disturbance stages; S3-4: After the target support recovers to the reference support axial force, compare the remaining deformation increment of the retaining wall at each monitoring point with the maximum deformation increment of the retaining wall in the corresponding disturbance stage. If the residual deformation limit is exceeded, discard the disturbance data for this time and reduce the axial force disturbance amount before re-executing step S2.

[0009] According to the above technical solution, in step S4, the load-holding stage... The median deformation increment of the retaining wall at each monitoring point is divided by the median axial force increment of the target support during the load-holding phase to obtain the load-load deformation response coefficient. The load reduction and maintenance phase will be in progress. The median deformation increment of the retaining wall at each monitoring point is divided by the median axial force increment of the target support during the load reduction and maintenance phase to obtain the load reduction deformation response coefficient. ; calculate the first according to the following formula Measured deformation response coefficients at monitoring points of the retaining wall: ,in, For the first The measured deformation response coefficients of each monitoring point of the retaining wall are used to correct the deformation response of the retaining wall in the initial stage model. The load maintenance phase The axial force transfer coefficient is obtained by dividing the median axial force increment of each support by the median axial force increment of the target support during the load holding phase. The load reduction and maintenance phase will be in progress. The axial force transmission coefficient is obtained by dividing the median axial force increment of each support by the median axial force increment of the target support during the load reduction and holding phase. ; calculate the first according to the following formula Measured axial force transmission coefficient of each support: ,in, For the first The measured axial force transmission coefficients of each support are used to correct the support axial force transmission response of the initial stage model.

[0010] According to the above technical solution, step S4 further includes: S4-1, In the initial stage model, apply the same axial force disturbance sequence as in step S2 to the target support, and obtain the result according to the calculation method described in claim 5. Simulated deformation response coefficients at monitoring points of the retaining wall and the Simulated axial force transmission coefficient of each support ; S4-2, calculate the following formula: Deformation response correction factor for each monitoring point of the retaining wall: ,in, For the first Deformation response correction coefficient for each monitoring point of the retaining wall; These are the measured deformation response coefficients; To simulate the deformation response coefficients; S4-3, calculate the following formula: Axial force transmission correction factor for each support: ,in, For the first Correction factor for axial force transmission of each support; This is the measured axial force transmission coefficient; To simulate the axial force transmission coefficient; S4-4, in the initial stage model, the... The deformation response value corresponding to each monitoring point of the retaining wall is multiplied by the deformation response correction coefficient, and then compared with the first... The axial force transmission amount corresponding to each support is multiplied by the axial force transmission correction coefficient to obtain the model for the current stage; where, when or When the absolute value is less than the preset minimum response value, the corresponding response data is discarded and the target support is redefined.

[0011] According to the above technical solution, step S5 includes: S5-1, establish candidate construction parameter groups based on preset values ​​for excavation layer thickness, excavation segment length, and support follow-up time limit, and input each candidate construction parameter group into the current stage model respectively; S5-2, Current stage model output (number) The simulated retaining wall deformation increment and simulated support axial force increment corresponding to each candidate construction parameter group; S5-3, calculate the following formula: The first candidate construction parameter group corresponding to the first Predicted deformation at monitoring points of the retaining wall: ,in, For the first The first candidate construction parameter group corresponding to the first Predicted deformation at monitoring points of the retaining wall; For the first The deformation of the reference retaining wall determined in step S1 at each retaining wall monitoring point; This is the deformation response correction factor; This represents the incremental deformation of the simulated retaining wall output by the model in the initial stage. S5-4, calculate the following formula: The first candidate construction parameter group corresponding to the first Predicted axial force for each support: ,in, For the first The first candidate construction parameter group corresponding to the first Predicted axial force of each support; For the first The reference support axial force determined in step S1; This is the correction factor for axial force transmission; This represents the incremental simulated support axial force output by the model in the initial stage.

[0012] According to the above technical solution, step S5 specifically includes: S5-5, compare the predicted deformation of each wall monitoring point with the corresponding deformation control limit, and compare the predicted axial force of each support with the corresponding design axial force upper limit; S5-6, remove candidate construction parameter groups where the predicted deformation at any monitoring point of the retaining wall reaches the corresponding deformation control limit, or the predicted axial force of any support reaches the corresponding design axial force upper limit. S5-7, sort the retained candidate construction parameter groups from largest to smallest according to the product of excavation layer thickness and excavation segment length, and determine the candidate construction parameter group with the largest product as the target construction parameter group; when the products of multiple candidate construction parameter groups are the same, determine the candidate construction parameter group with the longest support follow-up time limit as the target construction parameter group. S5-8, output the excavation layer thickness, excavation segment length and support follow-up time limit in the target construction parameter group, and return to step S1 after completing the corresponding excavation unit and support construction.

[0013] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: By first determining a stable monitoring range in which both the support axial force and the retaining wall deformation are in a stable state, the present invention can obtain the reference support axial force, the reference retaining wall deformation, and their background change trends; by sequentially implementing loading, recovery, unloading, and recovery again on the target support, and simultaneously extracting the incremental responses of the target support, adjacent supports, and the retaining wall, the influence of slow background changes on the response identification results can be reduced, and the deformation response of the retaining wall to the change of support axial force and the axial force transmission relationship between supports can be reflected respectively; by using the measured incremental response to correct the initial stage model, the accuracy of the current stage model in representing the actual incremental stress state of the deep foundation pit can be improved, and the inversion deviation caused by similar static monitoring results corresponding to different actual stress states can be reduced; furthermore, the current stage model is used to predict the retaining wall deformation and support axial force corresponding to different excavation layer thicknesses, excavation segment lengths, and support follow-up time limits, and the target construction parameter group is determined from the candidate construction parameter group that meets the deformation control limit and the upper limit of the design axial force, thereby improving the reliability of the determination of construction parameters for the next excavation unit. Attached Figure Description

[0014] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a flowchart illustrating the present invention. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] Please see Figure 1 This invention provides a technical solution: an adaptive control method for deep foundation pit construction parameters based on the joint inversion of support axial force and retaining wall deformation, comprising the following steps: S1, Determination of Stable Monitoring Interval: Receives axial force monitoring data of each support and deformation monitoring data of each monitoring point of the retaining wall during the current excavation stage; determines the stable monitoring interval where both the axial force of the supports and the deformation of the retaining wall are in a stable state based on the rate of change of the continuous monitoring data; outputs the benchmark axial force of the supports, the benchmark deformation of the retaining wall, and the corresponding trend of change within the stable monitoring interval. S2, Reversible axial force disturbance application: Based on the location of the next excavation unit, determine the target support from the supports already in operation; control the target support to sequentially complete the loading, recovery, unloading and recovery again, so that the axial force of the target support after the disturbance ends returns to the reference support axial force before the disturbance; output the actual axial force disturbance sequence of the target support and the time range of each disturbance stage; S3, Incremental response data extraction: During the actual axial force disturbance sequence, monitoring data of each monitoring point of the target support, adjacent support and retaining wall are collected simultaneously; according to the change trend output in step S1, the background change when no axial force disturbance is applied is removed from the monitoring data; the target support axial force increment, adjacent support axial force increment and retaining wall deformation increment corresponding to each disturbance stage are output; S4, Current Stage Response Relationship Inversion: Receive the initial stage model corresponding to the current construction state of the deep foundation pit, and apply the same axial force disturbance sequence as in step S2 to the initial stage model; determine the retaining wall deformation response correction coefficient and the support axial force transmission correction coefficient based on the incremental response data output in step S3 and the simulated incremental response output by the initial stage model; correct the initial stage model using the retaining wall deformation response correction coefficient and the support axial force transmission correction coefficient, and output the current stage model; S5, Determining Construction Parameters: Input multiple candidate construction parameter sets into the current stage model. Each candidate construction parameter set includes the excavation layer thickness, excavation segment length, and support follow-up time limit. Predict the retaining wall deformation and support axial force corresponding to each candidate construction parameter set, and eliminate candidate construction parameter sets whose prediction results exceed the remaining deformation allowance or the remaining support bearing capacity. Determine the construction parameters for the next excavation unit based on the retained candidate construction parameter sets and output the construction instructions. S1 includes: S1-1, receive axial force monitoring data of each support and deformation monitoring data of each monitoring point of the retaining wall at the same sampling time, and establish a continuous sliding interval according to the preset time length; S1-2, calculate the unit time change of the support axial force and the unit time change of the retaining wall deformation in each continuous sliding interval respectively; S1-3, when the unit time change of the axial force of all supports is less than the corresponding axial force stability threshold, and the unit time change of the deformation of all retaining walls is less than the corresponding deformation stability threshold, the continuous sliding interval is determined as the stability monitoring interval. S1-4, linear fitting is performed on the axial force monitoring data of each support and the deformation monitoring data of each monitoring point within the stable monitoring interval. The data at the beginning of the fitting is determined as the reference support axial force and the reference retaining wall deformation, and the fitting slope is determined as the corresponding trend. Step S1 involves simultaneously examining the continuous changes in the axial force of the support and the deformation of the retaining wall, selecting a time interval where both types of monitoring data remain stable, and determining the baseline state and slow change trend before the disturbance begins. This process allows for the separate retention of background processes, including continuous soil deformation, environmental changes, and slow changes during construction pauses, establishing a unified data starting point for subsequent identification of short-term responses caused by axial force disturbances. If disturbances are implemented at arbitrary times, background changes can easily overlap with the disturbance response, causing deviations in the relationship between the retaining wall deformation response and the axial force transmission. Therefore, a stable monitoring interval is a prerequisite for accurate extraction of subsequent field responses.

[0017] Step S2 includes: S2-1, the adjustable support that corresponds to the next excavation unit in the horizontal direction and is closest to the bottom of the next excavation unit in the vertical direction is determined as the target support; S2-2, determine the axial force disturbance amount based on the reference support axial force of the target support, the upper limit of the design axial force, and the preset disturbance ratio, so that the axial force of the target support after the load is increased is lower than the upper limit of the design axial force; S2-3, control the target support to increase the axial force disturbance from the reference support axial force, restore it to the reference support axial force, then decrease the axial force disturbance from the reference support axial force, and finally restore it to the reference support axial force; S2-4, During any disturbance stage, when the deformation increment of the retaining wall reaches the detection deformation limit, or the axial force of any support reaches the corresponding detection axial force limit, the current disturbance stage is terminated and the target support is controlled to recover to the reference support axial force. Steps S2-3 and S2-4 sequentially apply load, restore, reduce load, and restore again to the target support, inputting axial force changes in opposite directions and with controlled amplitudes into the retaining system without altering the final working axial force of the support. This axial force change is equivalent to applying a known short-term excitation to the current foundation pit stress system. The synchronous response of the retaining wall and adjacent supports to this excitation reflects the true load transfer state at the current construction stage. Conventional support pressure adjustment typically serves deformation control, and the support maintains a new axial force state after pressure adjustment. This step restores the original axial force after completing response acquisition and sets disturbance termination conditions, allowing the same support to simultaneously perform construction support and on-site condition detection functions, obtaining active response data usable for inversion without advancing the excavation process.

[0018] Step S3 includes: S3-1, Based on the reference support axial force, reference retaining wall deformation and change trend determined in step S1, calculate the background value of support axial force and the background value of retaining wall deformation at each sampling time during the axial force disturbance period; S3-2, subtract the corresponding background value of the support axial force from the actual support axial force at each sampling time to obtain the support axial force increment, and subtract the corresponding background value of the enclosure wall deformation from the actual enclosure wall deformation at each sampling time to obtain the enclosure wall deformation increment. S3-3, extract the median of the support axial force increment and the median of the retaining wall deformation increment within the preset sampling interval at the end of the load increase and load decrease stages, respectively, as the incremental response data for the corresponding disturbance stages; S3-4: After the target support recovers to the reference support axial force, the remaining deformation increment of the retaining wall at each monitoring point is compared with the maximum deformation increment of the retaining wall in the corresponding disturbance stage. If the residual deformation limit is exceeded, the disturbance data of this time is discarded and the axial force disturbance amount is reduced before step S2 is executed again. Step S3 first calculates the background axial force and background deformation during the disturbance period based on the changing trend within the stable monitoring interval, and then separates the incremental response directly caused by the axial force disturbance from the actual monitoring results. The loading and unloading stages provide response data in opposite directions, allowing for cross-verification and reducing the impact of monitoring zero-point drift, slow deformation of soft soil, and environmental factors on the identification results. After the target support restores the baseline axial force, steps S3-4 further check whether the retaining wall has any abnormal residual deformation, and re-acquire disturbance data exceeding the allowable range, excluding test results that have caused significant irreversible responses from the data entry point. Compared to directly using the absolute changes in axial force and deformation for inversion, this processing can retain effective responses with a clear correspondence to known disturbances, improving the comparability and reliability of the field response data.

[0019] In step S4, the load holding phase will be... The median deformation increment of the retaining wall at each monitoring point is divided by the median axial force increment of the target support during the load-holding phase to obtain the load-load deformation response coefficient. The load reduction and maintenance phase will be in progress. The median deformation increment of the retaining wall at each monitoring point is divided by the median axial force increment of the target support during the load reduction and maintenance phase to obtain the load reduction deformation response coefficient. ; calculate the first according to the following formula Measured deformation response coefficients at monitoring points of the retaining wall: ,in, For the first The measured deformation response coefficients of each monitoring point of the retaining wall are used to correct the deformation response of the retaining wall in the initial stage model. The load maintenance phase The axial force transfer coefficient is obtained by dividing the median axial force increment of each support by the median axial force increment of the target support during the load holding phase. The load reduction and maintenance phase will be in progress. The axial force transmission coefficient is obtained by dividing the median axial force increment of each support by the median axial force increment of the target support during the load reduction and holding phase. ; calculate the first according to the following formula Measured axial force transmission coefficient of each support: ,in, For the first The measured axial force transmission coefficient of each support is used to correct the support axial force transmission response of the initial stage model. Step S4 also includes: S4-1, In the initial stage model, the same axial force disturbance sequence as in step S2 is applied to the target support. Following the calculation method of claim 5, the following is obtained: Simulated deformation response coefficients at monitoring points of the retaining wall and the Simulated axial force transmission coefficient of each support ; S4-2, calculate the following formula: Deformation response correction factor for each monitoring point of the retaining wall: ,in, For the first Deformation response correction coefficient for each monitoring point of the retaining wall; These are the measured deformation response coefficients; To simulate the deformation response coefficients; S4-3, calculate the following formula: Axial force transmission correction factor for each support: ,in, For the first Correction factor for axial force transmission of each support; This is the measured axial force transmission coefficient; To simulate the axial force transmission coefficient; S4-4, in the initial stage model, the... The deformation response value corresponding to each monitoring point of the retaining wall is multiplied by the deformation response correction factor, and then compared with the first... The axial force transmission amount corresponding to each support is multiplied by the axial force transmission correction coefficient to obtain the model for the current stage; where, when or When the absolute value is less than the preset minimum response value, discard the corresponding response data and redetermine the target support; Steps S4-1 to S4-4 are the core of the joint inversion process of this invention. In the initial stage, after the model receives the same axial force disturbance as in the field, it outputs the deformation response of the retaining wall and the axial force transmission response of each support. These simulated responses are then compared item by item with the measured responses in the field. The deformation response of the retaining wall reflects the deformation constraint capacity jointly formed by the supports, the retaining wall, and the surrounding soil. The axial force transmission response of the supports reflects the degree of redistribution of the axial force change of the target support within the support system. Both types of responses jointly correct the initial stage model, distinguishing between changes in the actual deformation capacity of the retaining wall and monitoring changes caused by load transfer from adjacent supports. Conventional model correction typically uses single-item data of the retaining wall displacement or adjusts the overall model using a uniform ratio, easily achieving similar fitting results for various actual stress states. This step utilizes two types of synchronous responses generated by the same controllable disturbance to limit the direction of model correction, ensuring that the current stage model simultaneously conforms to the wall deformation law and the support load transmission law, reducing inversion bias caused by multiple interpretations of static monitoring data.

[0020] Step S5 includes: S5-1, establish candidate construction parameter groups based on preset values ​​for excavation layer thickness, excavation segment length, and support follow-up time limit, and input each candidate construction parameter group into the current stage model respectively; S5-2, Current stage model output (number) The simulated retaining wall deformation increment and simulated support axial force increment corresponding to each candidate construction parameter group; S5-3, calculate the following formula: The first candidate construction parameter group corresponding to the first Predicted deformation at monitoring points of the retaining wall: ,in, For the first The first candidate construction parameter group corresponding to the first Predicted deformation at monitoring points of the retaining wall; For the first The deformation of the reference retaining wall determined in step S1 at each retaining wall monitoring point; This is the deformation response correction factor; This represents the incremental deformation of the simulated retaining wall output by the model in the initial stage. S5-4, calculate the following formula: The first candidate construction parameter group corresponding to the first Predicted axial force for each support: ,in, For the first The first candidate construction parameter group corresponding to the first Predicted axial force of each support; For the first The reference support axial force determined in step S1; This is the correction factor for axial force transmission; The simulated support axial force increment output by the model in the initial stage; Step S5 specifically includes: S5-5, compare the predicted deformation of each wall monitoring point with the corresponding deformation control limit, and compare the predicted axial force of each support with the corresponding design axial force upper limit; S5-6, remove candidate construction parameter groups where the predicted deformation at any monitoring point of the retaining wall reaches the corresponding deformation control limit, or the predicted axial force of any support reaches the corresponding design axial force upper limit. S5-7: Sort the retained candidate construction parameter groups in descending order according to the product of the excavation layer thickness and the excavation segment length, and determine the candidate construction parameter group with the largest product as the target construction parameter group; when multiple candidate construction parameter groups have the same product, determine the candidate construction parameter group with the longest support follow-up time limit as the target construction parameter group. S5-8 outputs the excavation layer thickness, excavation segment length, and support follow-up time limit from the target construction parameter group, and returns to step S1 after completing the corresponding excavation unit and support construction.

[0021] Step S5 uses the current stage model to select construction parameters for the next excavation unit, allowing the model correction results to directly enter the construction control process. Different excavation layer thicknesses, excavation segment lengths, and support follow-up time limits correspond to different unloading ranges, spatial effect durations, and support constraint formation times. Based on these, the current stage model predicts retaining wall deformation and support axial force, and excludes construction parameter combinations that may exceed control limits. The ranking of retained schemes considers both excavation scale and support follow-up arrangements, ensuring that construction efficiency is based on the actual incremental stress capacity of the current foundation pit. This approach avoids the long-term use of fixed models formed in the design stage and reduces the lag of passively reducing construction parameters only after monitoring values ​​approach alarm limits, ensuring that each excavation unit uses the stress relationships identified on-site in the previous construction stage for decision-making.

[0022] This invention addresses the potential deviation between the construction stage model and the actual stress state of the foundation pit. It establishes a continuous processing procedure encompassing stable state selection, reversible axial force disturbance, incremental response separation, joint inversion of axial force and deformation, and screening of construction parameters. Reversible axial force disturbance provides a clearly defined on-site excitation for the current retaining system. Incremental response separation ensures a direct correspondence between the inversion data and this excitation. The joint inversion further utilizes the deformation of the retaining wall and the changes in axial force of adjacent supports to impose dual constraints on the model. The resulting current-stage model simultaneously reflects the deformation capacity of the retaining system and the load transfer relationship between supports. Based on this, the excavation layer thickness, excavation segment length, and support follow-up time limit for the next excavation unit are determined. This reduces the deviation in construction parameter judgment caused by similar static monitoring results corresponding to different actual stress states, and improves the matching degree between the layered and segmented construction parameters of deep foundation pits and the on-site stress state.

[0023] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0024] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An adaptive control method for deep foundation pit construction parameters based on the joint inversion of support axial force and retaining wall deformation, characterized in that: Includes the following steps: S1, Stable monitoring interval determination: Receive axial force monitoring data of each support and deformation monitoring data of each monitoring point of the retaining wall during the current excavation stage; Based on the rate of change of continuous monitoring data, a stable monitoring range in which both the axial force of the support and the deformation of the retaining wall are in a stable state is determined. Output the reference support axial force, reference retaining wall deformation, and corresponding trends within the stable monitoring interval; S2, Reversible axial force disturbance application: Based on the position of the next excavation unit, determine the target support from the supports that have been put into operation; control the target support to sequentially complete the loading, recovery, unloading and recovery again, so that the axial force of the target support after the disturbance ends returns to the reference support axial force before the disturbance; Output the actual axial force disturbance sequence of the target support and the time range of each disturbance stage; S3, Incremental response data extraction: During the application of the actual axial force disturbance sequence, monitoring data of each monitoring point of the target support, adjacent support and retaining wall are collected simultaneously; Based on the changing trend output in step S1, remove the background changes from the monitoring data when no axial force disturbance was applied; Output the target support axial force increment, adjacent support axial force increment, and retaining wall deformation increment corresponding to each disturbance stage; S4, Current stage response relationship inversion: Receive the initial stage model corresponding to the current construction state of the deep foundation pit, and apply the same axial force disturbance sequence as in step S2 to the initial stage model; determine the retaining wall deformation response correction coefficient and the support axial force transmission correction coefficient based on the incremental response data output in step S3 and the simulated incremental response output by the initial stage model. The initial stage model is corrected using the deformation response correction coefficient of the retaining wall and the axial force transmission correction coefficient of the support, and the current stage model is output. S5, Determining construction parameters: Input multiple candidate construction parameter groups into the current stage model respectively. Each candidate construction parameter group includes the excavation layer thickness, excavation segment length, and support follow-up time limit; predict the retaining wall deformation and support axial force corresponding to each candidate construction parameter group, and eliminate candidate construction parameter groups whose prediction results exceed the remaining deformation allowance or the remaining support bearing capacity; determine the construction parameters of the next excavation unit based on the retained candidate construction parameter groups and output the construction instructions.

2. The adaptive control method for deep foundation pit construction parameters based on the joint inversion of support axial force and retaining wall deformation according to claim 1, characterized in that: S1 includes: S1-1, receive axial force monitoring data of each support and deformation monitoring data of each monitoring point of the retaining wall at the same sampling time, and establish a continuous sliding interval according to the preset time length; S1-2, calculate the unit time change of the support axial force and the unit time change of the retaining wall deformation in each continuous sliding interval respectively; S1-3, when the unit time change of the axial force of all supports is less than the corresponding axial force stability threshold, and the unit time change of the deformation of all retaining walls is less than the corresponding deformation stability threshold, the continuous sliding interval is determined as the stability monitoring interval. S1-4, perform linear fitting on the axial force monitoring data of each support and the deformation monitoring data of each monitoring point within the stable monitoring interval, determine the data at the starting time of the fitting as the reference support axial force and the reference retaining wall deformation, and determine the fitting slope as the corresponding trend of change.

3. The adaptive control method for deep foundation pit construction parameters based on the joint inversion of support axial force and retaining wall deformation according to claim 2, characterized in that: Step S2 includes: S2-1, the adjustable support that corresponds to the next excavation unit in the horizontal direction and is closest to the bottom of the next excavation unit in the vertical direction is determined as the target support; S2-2, Determine the axial force disturbance amount based on the reference support axial force of the target support, the upper limit of the design axial force, and the preset disturbance ratio, so that the axial force of the target support after the load increase is lower than the upper limit of the design axial force; S2-3, control the target support to increase the axial force disturbance from the reference support axial force, restore it to the reference support axial force, then decrease the axial force disturbance from the reference support axial force, and finally restore it to the reference support axial force; S2-4. During any disturbance phase, when the deformation increment of the retaining wall reaches the detection deformation limit, or the axial force of any support reaches the corresponding detection axial force limit, the current disturbance phase is terminated and the target support is controlled to return to the reference support axial force.

4. The adaptive control method for deep foundation pit construction parameters based on the joint inversion of support axial force and retaining wall deformation according to claim 3, characterized in that: Step S3 includes: S3-1, Based on the reference support axial force, reference retaining wall deformation and change trend determined in step S1, calculate the background value of support axial force and the background value of retaining wall deformation at each sampling time during the axial force disturbance period; S3-2, subtract the corresponding background value of the support axial force from the actual support axial force at each sampling time to obtain the support axial force increment, and subtract the corresponding background value of the enclosure wall deformation from the actual enclosure wall deformation at each sampling time to obtain the enclosure wall deformation increment. S3-3, extract the median of the support axial force increment and the median of the retaining wall deformation increment within the preset sampling interval at the end of the load increase and load decrease stages, respectively, as the incremental response data for the corresponding disturbance stages; S3-4: After the target support recovers to the reference support axial force, compare the remaining deformation increment of the retaining wall at each monitoring point with the maximum deformation increment of the retaining wall in the corresponding disturbance stage. If the residual deformation limit is exceeded, discard the disturbance data for this time and reduce the axial force disturbance amount before re-executing step S2.

5. The adaptive control method for deep foundation pit construction parameters based on the joint inversion of support axial force and retaining wall deformation according to claim 4, characterized in that: In step S4, the load holding phase will be... The median deformation increment of the retaining wall at each monitoring point is divided by the median axial force increment of the target support during the load-holding phase to obtain the load-load deformation response coefficient. The load reduction and maintenance phase will be in progress. The median deformation increment of the retaining wall at each monitoring point is divided by the median axial force increment of the target support during the load reduction and maintenance phase to obtain the load reduction deformation response coefficient. ; calculate the first according to the following formula Measured deformation response coefficients at monitoring points of the retaining wall: ,in, For the first The measured deformation response coefficients of each monitoring point of the retaining wall are used to correct the deformation response of the retaining wall in the initial stage model. The load maintenance phase The axial force transfer coefficient is obtained by dividing the median axial force increment of each support by the median axial force increment of the target support during the load holding phase. The load reduction and maintenance phase will be in progress. The axial force transmission coefficient is obtained by dividing the median axial force increment of each support by the median axial force increment of the target support during the load reduction and holding phase. ; calculate the first according to the following formula Measured axial force transmission coefficient of each support: ,in, For the first The measured axial force transmission coefficients of each support are used to correct the support axial force transmission response of the initial stage model.

6. The adaptive control method for deep foundation pit construction parameters based on the joint inversion of support axial force and retaining wall deformation according to claim 5, characterized in that: Step S4 further includes: S4-1, In the initial stage model, apply the same axial force disturbance sequence as in step S2 to the target support, and obtain the result according to the calculation method described in claim 5. Simulated deformation response coefficients at monitoring points of the retaining wall and the Simulated axial force transmission coefficient of each support ; S4-2, calculate the following formula: Deformation response correction factor for each monitoring point of the retaining wall: ,in, For the first Deformation response correction coefficient for each monitoring point of the retaining wall; These are the measured deformation response coefficients; To simulate the deformation response coefficients; S4-3, calculate the following formula: Axial force transmission correction factor for each support: ,in, For the first Correction factor for axial force transmission of each support; This is the measured axial force transmission coefficient; To simulate the axial force transmission coefficient; S4-4, in the initial stage model, the... The deformation response value corresponding to each monitoring point of the retaining wall is multiplied by the deformation response correction coefficient, and then compared with the first... The axial force transmission amount corresponding to each support is multiplied by the axial force transmission correction coefficient to obtain the model for the current stage; where, when or When the absolute value is less than the preset minimum response value, the corresponding response data is discarded and the target support is redefined.

7. The adaptive control method for deep foundation pit construction parameters based on the joint inversion of support axial force and retaining wall deformation according to claim 6, characterized in that: Step S5 includes: S5-1, establish candidate construction parameter groups based on preset values ​​for excavation layer thickness, excavation segment length, and support follow-up time limit, and input each candidate construction parameter group into the current stage model respectively; S5-2, Current stage model output (number) The simulated retaining wall deformation increment and simulated support axial force increment corresponding to each candidate construction parameter group; S5-3, calculate the following formula: The first candidate construction parameter group corresponding to the first Predicted deformation at monitoring points of the retaining wall: ,in, For the first The first candidate construction parameter group corresponding to the first Predicted deformation at monitoring points of the retaining wall; For the first The deformation of the reference retaining wall determined by each retaining wall monitoring point in step S1; This is the deformation response correction factor; This represents the incremental deformation of the simulated retaining wall output by the model in the initial stage. S5-4, calculate the following formula: The first candidate construction parameter group corresponding to the first Predicted axial force for each support: ,in, For the first The first candidate construction parameter group corresponding to the first Predicted axial force of each support; For the first The reference support axial force determined in step S1; This is the correction factor for axial force transmission; This represents the incremental simulated support axial force output by the model in the initial stage.

8. The adaptive control method for deep foundation pit construction parameters based on the joint inversion of support axial force and retaining wall deformation according to claim 7, characterized in that: Step S5 specifically includes: S5-5, compare the predicted deformation of each wall monitoring point with the corresponding deformation control limit, and compare the predicted axial force of each support with the corresponding upper limit of the design axial force; S5-6, remove candidate construction parameter groups where the predicted deformation at any monitoring point of the retaining wall reaches the corresponding deformation control limit, or the predicted axial force of any support reaches the corresponding design axial force upper limit. S5-7, sort the retained candidate construction parameter groups from largest to smallest according to the product of excavation layer thickness and excavation segment length, and determine the candidate construction parameter group with the largest product as the target construction parameter group; when the products of multiple candidate construction parameter groups are the same, determine the candidate construction parameter group with the longest support follow-up time limit as the target construction parameter group. S5-8, output the excavation layer thickness, excavation segment length and support follow-up time limit in the target construction parameter group, and return to step S1 after completing the corresponding excavation unit and support construction.

Images