A pile foundation jack force control method and system for underpassing existing station underground excavation construction

Abstract

The present application relates to the technical field of construction technology of underpassing existing station, in particular to a method and system for force control of pile foundation jacks in underpassing existing station excavation construction, the present application first collects information such as the position of the construction pile in the underpassing construction area, the load of the existing station, the rigidity of the bottom plate of the existing station, and the geological information of the stratum where the construction pile is located, uses the above information to construct a finite element analysis model, and uses the finite element analysis model to simulate stress change sample data generated when multiple construction piles are subjected to changes. Then, the stress change sample data is fitted to construct a stress relationship model reflecting the stress change relationship of different construction piles. When performing pressure analysis, if an unbalanced pressure condition occurs, the stress relationship model can be used to adjust and control the force of the construction pile with abnormal stress to avoid exacerbating the local stress imbalance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of underpassing existing station construction, and particularly relates to a method and system for force control of pile foundation jacks in underpassing existing station excavation construction. BACKGROUND

[0002] Figure 1 A structural diagram for underpassing existing station excavation construction is shown in FIG. 1. When underpassing construction is performed at the bottom of an existing station, an excavation construction passage is needed, and then a construction pile is erected in the construction passage. The top of the construction pile is used to support the bottom plate of the bottom of the existing station, and a jack is arranged for support force adjustment. The bottom of the construction pile is supported by rock soil. After the construction is completed, the lower station top plate is poured, and the existing station bottom is stable. Then, the construction pile and the jack are removed. Figure 1

[0003] In the above process, the support force of the rock soil is not constant. Due to the change of the support force of the rock soil caused by underground water activity, the support force of the construction pile on the bottom plate of the bottom of the existing station will change locally. Therefore, the jack needs to be adjusted to maintain the force balance of multiple positions of the bottom plate of the bottom of the existing station. The prior art, such as a method for underpassing existing subway station by large-section excavation in CN117780358A, records that a self-locking jack 3 is arranged between a support pile 1 and a steel pipe support 2. During the construction process, the axial force of the jack is actively adjusted according to the monitoring data to ensure the operation safety of the existing station. Therefore, in the prior art, the jack is manually adjusted according to the monitoring data. However, since multiple jacks are arranged, and the forces of the multiple jacks will affect each other, the control of a single point may trigger a chain reaction (for example, adjusting the force of one jack causes the force of the adjacent point to suddenly change), which may even exacerbate the imbalance. SUMMARY

[0004] Therefore, the present application aims to provide a method and system for force control of pile foundation jacks in underpassing existing station excavation construction to solve the above technical problems.

[0005] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0006] The method for force control of pile foundation jacks in underpassing existing station excavation construction comprises the following steps:

[0007] Obtain the position of the construction pile in the underpassing construction area, the load of the existing station, the rigidity of the bottom plate of the existing station, and the geological information of the stratum where the construction pile is located. Obtain real-time pressure data of the jack at the top of the construction pile.

[0008] ​construct a finite element analysis model based on the position of the construction pile in the construction area, the load of the existing station, the stiffness of the bottom plate of the existing station, and geological information of the stratum where the construction pile is located, and simulate force changes of the construction pile based on the finite element analysis model to obtain a plurality of sets of force change sample data, wherein each set of force change sample data includes value changes of forces of other construction piles when a force of one of the construction piles deviates from a set value by different degrees;

[0009] construct a force relationship model of the plurality of construction piles based on the plurality of sets of force change sample data, wherein the force relationship model represents changes in forces of other construction piles when forces of different construction piles deviate from a set value by different degrees;

[0010] perform balance state analysis on the real-time pressure data, and when the real-time pressure data is in an unbalanced state, plan force adjustment amounts of the jacks based on the real-time pressure data and the force relationship model to obtain force adjustment amounts of one or more jacks, and control forces of the jacks based on the force adjustment amounts of the one or more jacks.

[0011] The application also provides a jack force control system for a construction pile of a construction pile of a construction area under an existing station, comprising:

[0012] an acquisition module configured to acquire the position of the construction pile in the construction area, the load of the existing station, the stiffness of the bottom plate of the existing station, and geological information of the stratum where the construction pile is located, and acquire real-time pressure data of the jacks at the top of the construction pile;

[0013] a simulation module configured to construct a finite element analysis model based on the position of the construction pile in the construction area, the load of the existing station, the stiffness of the bottom plate of the existing station, and geological information of the stratum where the construction pile is located, and simulate force changes of the construction pile based on the finite element analysis model to obtain a plurality of sets of force change sample data, wherein each set of force change sample data includes value changes of forces of other construction piles when a force of one of the construction piles deviates from a set value by different degrees;

[0014] a relationship model construction module configured to construct a force relationship model of the plurality of construction piles based on the plurality of sets of force change sample data, wherein the force relationship model represents changes in forces of other construction piles when forces of different construction piles deviate from a set value by different degrees;

[0015] An analysis and control module is configured to perform balanced state analysis on the real-time pressure data, and when the real-time pressure data is in an unbalanced state, to perform force adjustment amount planning based on the real-time pressure data and the force relationship model, to obtain force adjustment amounts of one or more jacks; and to perform force control on the jacks based on the force adjustment amounts of the one or more jacks.

[0016] The method and system for controlling the force of jacks in pile foundation in underground excavation construction under existing stations according to the present application first collects information such as the positions of construction piles in the area under construction, the load of the existing station, the rigidity of the bottom plate of the existing station, and the geological information of the stratum where the construction piles are located, uses the above information to construct a finite element analysis model, and uses the finite element analysis model to simulate sample data of force changes of multiple construction piles when the construction piles are subjected to changes. Then, the sample data of force changes are fitted to construct a force relationship model reflecting the force change relationship of different construction piles. When performing pressure analysis, if an unbalanced pressure condition occurs, the force relationship model can be used to adjust and control the force of the construction pile with abnormal force to avoid exacerbating the local force imbalance. BRIEF DESCRIPTION OF DRAWINGS

[0017] The present application will be further described below in conjunction with the drawings and embodiments:

[0018] Figure 1 A structural schematic diagram of underground excavation construction under existing stations;

[0019] Figure 2 A use scene diagram of the method for controlling the force of jacks in pile foundation in underground excavation construction under existing stations in an embodiment of the present application;

[0020] Figure 3 A flowchart of the method for controlling the force of jacks in pile foundation in underground excavation construction under existing stations in an embodiment of the present application;

[0021] Figure 4 A flowchart of the optimal solution iteration in an embodiment of the present application;

[0022] Figure 5 A structural diagram of the system for controlling the force of jacks in pile foundation in underground excavation construction under existing stations in an embodiment of the present application. DETAILED DESCRIPTION

[0023] Figure 2 A use scene diagram of the method for controlling the force of jacks in pile foundation in underground excavation construction under existing stations in an embodiment of the present application, as Figure 2As shown, the computer device 210 is used to construct a three-dimensional model and a finite element analysis model, and simulation data is obtained through simulation analysis. In addition, the hydraulic data of the jack is collected to convert into stress data of the pressure change sensor 220 at the top of the construction pile, or the pressure change sensor is directly set. The stress data is transmitted to the computer device 210 for analysis and processing, and the computer device 210 sends a control signal to the PLC programmable device 230 according to the analysis and processing result, and the PLC programmable device 230 controls the hydraulic pump and valve and other components in the hydraulic system 240 according to the control signal, so as to realize closed-loop control of the jack 250.

[0024] Figure 3 The flow chart of the pile-jack force control method for the underpassing existing station underground construction pile in an embodiment of the present application is shown in Figure 3 As shown, the pile-jack force control method for the underpassing existing station underground construction pile in the present application comprises:

[0025] S310, obtaining the position of the construction pile in the underpassing construction area, the load of the existing station, the stiffness of the bottom plate of the existing station, and the geological information of the stratum where the construction pile is located; and obtaining the real-time pressure data of the jack at the top of the construction pile;

[0026] In the present application, the coordinates, spacing, and buried depth of the construction pile are directly obtained from the construction drawings. The pile position can also be laid out on site by using a total station, RTK (real-time kinematic positioning), and other measuring equipment to verify the consistency of the design drawings and the actual construction.

[0027] The original design load (including static load and dynamic load) of the existing station is obtained from the design file, such as track load, train operation load, equipment weight, etc.

[0028] The stiffness of the bottom plate of the existing station can also be obtained from the design file.

[0029] The stiffness of the bottom plate of the existing station is extracted from the exploration data in the early stage of construction.

[0030] S320, constructing a finite element analysis model based on the position of the construction pile in the underpassing construction area, the load of the existing station, the stiffness of the bottom plate of the existing station, and the geological information of the stratum where the construction pile is located, and simulating the stress change of the construction pile based on the finite element analysis model to obtain a plurality of sets of stress change sample data, wherein each set of stress change sample data includes the value change of the stress of the other construction piles when the stress of one of the construction piles deviates from the set value to different degrees;

[0031] Because the arrangement position of the construction pile, the stratum parameter, and the existing station load are not the same in different underpass construction scenes, the stress analysis data in different situations cannot be directly used, and thus the construction data of other subway construction projects cannot be used for reference. In this embodiment, the finite element analysis is used to determine the stress change of the construction pile, and the change of other construction piles is determined.

[0032] The specific process of constructing the finite element model is as follows:

[0033] S321, a three-dimensional model of the existing station and the underpass construction area is constructed based on the position of the construction pile in the underpass construction area;

[0034] When the three-dimensional model is constructed, a three-dimensional geometric model of the station bottom plate, side wall, top plate, column, beam, and the like is established first. The pile body is embedded in the model as a solid element or a beam element and needs to be in contact with the soil layer. The soil body model is established according to the geological stratification and simplified by using a layered medium.

[0035] S322, material attribute definition is performed on the three-dimensional model based on the stiffness of the existing station bottom plate and the geological information of the stratum where the construction pile is located, boundary constraint is performed on the three-dimensional model, and load is applied to the three-dimensional model based on the load of the existing station, to obtain a finite element analysis model.

[0036] For the concrete material and the stratum, the elastic modulus, density, Poisson's ratio, and compressive / tensile strength need to be defined. Then, the bottom constraint and the lateral constraint are performed. The lateral constraint is used to fix the degrees of freedom (UX, UY, UZ) of the model bottom. The lateral constraint is used to set the lateral displacement constraint (such as normal degree of freedom release) according to the geological condition.

[0037] In addition, the pile-soil interaction and the contact attribute (such as friction coefficient, normal stiffness, and tangential stiffness) of the pile and the soil body need to be defined.

[0038] Finally, the load is applied. The load is a static load (station structure dead weight: applied by dead load) and a dynamic load. The dynamic load is the load generated by the operation of the existing station above. The average value is calculated by collecting data and added to the static load to obtain the total load.

[0039] After the model is constructed, the finite element model is used to simulate the stress change. The specific process is as follows:

[0040] S11, a current construction pile is selected, and the stress of the current construction pile is adjusted multiple times. The adjustment amount of each stress adjustment is n x ΔF or -n x ΔF. The stress change amount of other construction piles is recorded at each adjustment, to obtain a group of stress change sample data. n is the adjustment number, and ΔF is the adjustment amount of single adjustment.

[0041] In the actual monitoring process, the single maximum settlement tolerance value of the station is 3mm, and the corresponding single construction pile jack stress change amount is between 100kN-150kN. Therefore, 150kN is divided into n adjustment amounts, 2n adjustment amounts are obtained from-150kN to 150kN, and the stress of the single pile in the model is adjusted in sequence, so as to simulate the possible stress change in the actual process, and record the stress change amount of other piles. Thus, the simulated basic data is obtained.

[0042] S12, the next construction pile is taken as the current construction pile, and step S11 is returned until the stress adjustment of all construction piles is completed, and a plurality of groups of stress change sample data are obtained.

[0043] The plurality of groups of stress change sample data in the application are based on each construction pile as the independent variable and other construction piles as the dependent variable. The basic data is obtained by sequentially performing experimental simulation.

[0044] S330, a stress relationship model of the plurality of construction piles is constructed based on the plurality of groups of stress change sample data, wherein the stress relationship model represents the change of the stress of other construction piles when the stress of different construction piles deviates from the set value to different degrees;

[0045] In the application, the total load of the existing vehicle and the load of all construction piles are the same. Under ideal conditions (the bottom plate is an absolute rigid body), the relationship between the stress influence of different construction piles is linear, for example, the increase of pile A is equal to the decrease of pile B. However, in fact, due to the complex position relationship between the plurality of construction piles and the fact that the bottom plate of the existing station is not an absolute rigid body, a quadratic nonlinear relationship is used to describe the stress change relationship between different construction piles.

[0046] The construction process of the stress relationship model is as follows:

[0047] S331, for each group of stress change sample data, a quadratic nonlinear relationship equation is constructed, wherein the mathematical expression of the quadratic nonlinear relationship equation is:

[0048]

[0049] In the formula, ΔF i is the stress change amount of the current construction pile in the current group of stress change sample data, ΔF j is the stress change amount of the jth other construction pile in the current group of stress change sample data, a j is the quadratic term to be estimated parameter of the jth other construction pile, b j is the linear term to be estimated parameter of the jth other construction pile, and c ja j is the estimated offset parameter of the jth other construction pile;

[0050] S332, each group of stress change sample data is brought into a quadratic nonlinear relationship equation for fitting to obtain a nonlinear relationship equation for representing the corresponding change of the construction pile j when the construction pile i changes in stress; and a stress relationship model is constructed based on the plurality of nonlinear relationship equations.

[0051] In this application, the least squares method is used to fit the above quadratic nonlinear relationship equation, and the core idea is to solve the polynomial coefficients by minimizing the sum of squares of errors. The specific process includes:

[0052] For the m groups of data that exist, m = 2n, the following design matrix A and target vector B are constructed;

[0053]

[0054] The target is to solve the coefficient vector β, β = [a j ,b j ,c j ] T , so that Aβ≈B;

[0055] By minimizing the sum of squares of errors E, E = ‖Aβ-B‖ 2 , the linear equation is obtained:

[0056] A T Aβ=A T B

[0057] Solving the above linear equation, the parameters a j ,b j ,c j can be obtained, thereby completing the fitting of the above quadratic nonlinear relationship equation.

[0058] S340, the real-time pressure data is analyzed for a balanced state, and when the real-time pressure data is in an unbalanced state, a force adjustment amount planning is performed based on the real-time pressure data and the stress relationship model to obtain a force adjustment amount of one or more jacks; and the force adjustment amount of the one or more jacks is used to control the force of the jacks.

[0059] After the stress relationship model is constructed, the stress relationship model can be used to participate in the force control process of the plurality of jacks.

[0060] In this application, the stress balance state is analyzed in real time to determine whether there is a stress imbalance. If there is a stress imbalance, it may cause rapid increase of the settlement of the existing station.

[0061] The analysis process of the force balance state is as follows:

[0062] (1) extracting a pressure data sequence {F1, F2,..., F j ,F j+1} of the current time point from the real-time pressure data, wherein the subscripts 1 to j+1 are all construction pile serial numbers;

[0063] (2) calculating the variance Var(F1, F2,..., F j ,F j+1 ) of all construction pile top jack pressure data in the pressure data sequence, and calculating the difference between each pressure data in the pressure data sequence {F1, F2,..., F j ,F j+1} and the preset reference force F to obtain a pressure change data sequence {(F1-F), (F2-F),..., (F j -F), (F j+1 -F)};

[0064] (3) when the variance Var(F1, F2,..., F j ,F j+1 ) is greater than a preset variance threshold, or any one of the pressure change values in the pressure change data sequence {(F1-F), (F2-F),..., (F j -F), (F j+1 -F)} is greater than a preset change threshold, it is determined that the real-time pressure data is unstable, otherwise, it is determined that the real-time pressure data is stable.

[0065] The application reflects the overall stable state by collecting variance, and reflects the local stable state by comparing the pressure threshold. The variance measures the dispersion degree of all construction pile pressure values. If the variance is too large, it means that the pile pressure difference is significant, which may imply a potential unstable state. When there is a pressure change value greater than the preset change threshold, it can directly indicate that the settlement has started, and the force of the corresponding jack needs to be adjusted.

[0066] If the analysis result of the real-time pressure data is unstable, further jack force adjustment control is needed, and the specific process is as follows:

[0067] (1) determining the adjustment amount; the application constructs an optimization problem, introduces a force relationship model into the value optimization problem, and solves the optimal solution under the constraint condition, including:

[0068] S21, constructing an objective function with the minimum pressure data variance as the target, and configuring a total load balance constraint condition and a force range constraint condition for limiting the force of a single construction pile;

[0069] When the pressure data variance is minimized, it can be approximately considered that the pressure data of each construction pile is almost the same, at this time, it is in a balanced and stable state, and the horizontal state of the existing station floor can also be maintained.

[0070] The mathematical expression of the target function is as follows:

[0071] Mini Var(F′1,F′2,...,F′ j ,F′ j+1 )

[0072] In the formula, F′1~F′ j+1 respectively represent the force of the jack at the top of the construction pile after the force adjustment;

[0073] The mathematical expression of the total load balance constraint condition is as follows:

[0074] ∑(F′1,F′2,...,F′ j ,F′ j+1 )∈P total ±P total ×ρ

[0075] In the formula, P total is the total load of the existing station, and ρ is a deviation tolerance ratio;

[0076] Since the actual load of the existing station is not constant, there is a dynamic load. Therefore, it is impossible to strictly limit ∑(F′1,F′2,...,F′ j ,F′ j+1 )=P total Therefore, the present application limits that the total force of the multiple construction piles is within 5% of the total load of the existing station, that is, ρ=5%.

[0077] The mathematical expression of the force range constraint condition of the force is as follows:

[0078] F min ≤F′ j ≤F max

[0079] In the formula, F min is the minimum force, and F max is the maximum force;

[0080] In order to ensure that the force adjustment of the jack of one construction pile does not aggravate the local force imbalance, the present application also limits the force range of each construction pile to ensure that the force of the construction pile does not exceed this range in the subsequent adjustment process.

[0081] S22, extracting a target construction pile with the largest deviation from the preset reference force F from the real-time pressure data, and updating the force of the jack of the target construction pile under the total load balance constraint condition and the force range constraint condition, calculating the variance of a plurality of force data each time the updating is performed until the variance is minimized;

[0082] Figure 4 An optimal solution iteration flowchart in an embodiment of the present application is shown in FIG. 1. In this embodiment, the optimal solution is approached by adjusting one by one. First, a target construction pile with the largest deviation from the preset reference force F is extracted from the real-time pressure data. The force of the target construction pile is updated, and the specific process is as follows: Figure 4

[0083] (1) determining an initial adjustment amount ΔF0, and simulating the adjustment of the force of the target construction pile based on the initial adjustment amount, and updating the real-time pressure data after the adjustment is completed;

[0084] (2) obtaining the variance Var0 at the last update and the current variance Var1, and obtaining the initial variance Var base before the update is performed;

[0085] (3) determining the adjustment amount ΔF next for the next update based on the variance Var0 at the last update, the current variance Var1 and the initial variance Var base , and the mathematical expression of the adjustment amount ΔF next for the next update is:

[0086]

[0087] In the formula, ΔF is the set maximum single adjustment amount.

[0088] In this embodiment, in order to ensure the adjustment speed while also ensuring the adjustment accuracy, the present application adopts dynamic adjustment amount control. The adjustment amount ΔF next for the next update is determined based on the variance change rate of the last adjustment. Therefore, when the variance change rate is relatively large at the early stage of adjustment, a larger adjustment amount is used. When the variance change rate is relatively low near the fitting, a smaller adjustment amount is automatically switched to, so as to ensure the adjustment accuracy.

[0089] (4) repeating steps (2)-(3), if the variance no longer decreases but increases, or if the constraint condition is broken during the adjustment, the update is stopped. The adjustment amount at the time when the variance is the smallest is taken as the adjustment amount of the target construction pile at present, and the adjustment amount at this time satisfies the variance minimization in the objective function.

[0090] ​​S23, when the variance of the plurality of stress data is minimized, comparing the variance with a preset variance threshold value, if the variance is greater than the preset variance threshold value, returning to step S22 until the variance is less than or equal to the preset variance threshold value; when the variance is less than or equal to the preset variance threshold value, obtaining the force adjustment amount of one or more jacks.

[0091] In many cases, only adjusting a single construction pile cannot achieve the optimal effect, therefore, a smaller variance threshold (tolerance threshold) is set in the present application, if the overall variance cannot reach below the tolerance threshold after the first update adjustment, returning to step S22 and performing the cycle. Thus, the theoretical adjustment amount of one or more construction piles is obtained.

[0092] After obtaining the theoretical adjustment amount of one or more construction piles, a control signal can be generated based on the theoretical adjustment amount of one or more construction piles to control the force of the jacks at the top of one or more construction piles. In the embodiment, PID closed-loop control is used to perform force control adjustment of the jacks based on closed-loop control.

[0093] The present application provides a method for controlling the force of jacks in a pile foundation for underground excavation construction under an existing station, which first collects information such as the positions of construction piles in the construction area under the existing station, the load of the existing station, the stiffness of the bottom plate of the existing station, and the geological information of the stratum where the construction piles are located, uses the above information to construct a finite element analysis model, and uses the finite element analysis model to simulate stress change sample data generated when the plurality of construction piles are subjected to changes. Then, the stress change sample data is fitted to construct a stress relationship model reflecting the stress change relationship of different construction piles. When performing stress analysis, if the pressure is unbalanced, the stress relationship model can be used to control the force adjustment of the construction pile with abnormal stress to avoid exacerbating the local stress imbalance.

[0094] As shown in Figure 5 The present application also provides a system for controlling the force of jacks in a pile foundation for underground excavation construction under an existing station, which comprises:

[0095] An acquisition module is configured to acquire the positions of construction piles in the construction area under the existing station, the load of the existing station, the stiffness of the bottom plate of the existing station, and the geological information of the stratum where the construction piles are located, and to acquire real-time pressure data of jacks at the top of the construction piles.

[0096] An analog module is configured to construct a finite element analysis model based on the positions of the construction piles in the underpass construction area, the load of the existing station, the stiffness of the floor of the existing station and the geological information of the stratum where the construction piles are located, and simulate the stress change of the construction piles based on the finite element analysis model to obtain a plurality of sets of stress change sample data, wherein each set of stress change sample data includes the value change of the stress of other construction piles when the stress of one of the construction piles deviates from a set value by different degrees.

[0097] A relationship model construction module is configured to construct a stress relationship model of the plurality of construction piles based on the plurality of sets of stress change sample data, wherein the stress relationship model represents the change of the stress of other construction piles when the stress of different construction piles deviates from a set value by different degrees.

[0098] An analysis and control module is configured to perform balance state analysis on the real-time pressure data, and when the real-time pressure data is in an unbalanced state, plan the force adjustment amount of the jacks based on the real-time pressure data and the stress relationship model to obtain the force adjustment amount of one or more jacks, and control the force of the jacks based on the force adjustment amount of the one or more jacks.

[0099] The jack force control system for the underpass construction pile foundation of the underpass existing station excavation construction of the present application first collects the positions of the construction piles in the underpass construction area, the load of the existing station, the stiffness of the floor of the existing station and the geological information of the stratum where the construction piles are located, constructs a finite element analysis model using the above information, and simulates the stress change sample data generated when the stress of a plurality of construction piles changes using the finite element analysis model. Then, the stress change sample data is fitted to construct a stress relationship model that reflects the stress change relationship of different construction piles. When performing pressure analysis, if the pressure is unbalanced, the stress relationship model can be used to adjust and control the force of the construction pile with abnormal stress to avoid exacerbating the local stress imbalance.

Claims

1. A method for controlling the force application of jacks in the construction of underground tunnels for existing stations, characterized in that... Including the following steps: The system acquires information on the location of the construction piles in the construction area, the load on the existing station, the stiffness of the existing station slab, and the geological information of the strata where the construction piles are located; and it also acquires real-time pressure data of the jacks at the top of the construction piles. Based on the location of the construction piles in the underpass construction area, the load of the existing station, the stiffness of the existing station floor slab, and the geological information of the strata where the construction piles are located, a finite element analysis model is constructed. Based on the finite element analysis model, the stress change of the construction piles is simulated, and multiple sets of stress change sample data are obtained. Each set of stress change sample data includes the stress changes of other construction piles when the stress of one construction pile deviates from the set value to a different degree. Based on the multiple sets of force change sample data, a force relationship model for multiple construction piles is constructed. The force relationship model characterizes the changes in the force of other construction piles when the force of different construction piles deviates from the set value to different degrees. The real-time pressure data is analyzed for equilibrium. When the real-time pressure data is in an unbalanced state, the force adjustment amount is planned based on the real-time pressure data and the force relationship model to obtain the force adjustment amount of one or more jacks. The force control of the jacks is then performed based on the force adjustment amount of the one or more jacks. The process includes: S21, constructing an objective function aimed at minimizing the variance of the pressure data, and configuring total load balance constraints and force range constraints to limit the force on a single construction pile; wherein the mathematical expression of the objective function is: In the formula, These represent the forces exerted on the jacks at the top of the construction pile after the applied force is adjusted; the mathematical expression for the total load balance constraint condition is: In the formula, The total load of existing stations, The deviation tolerance ratio is used; the mathematical expression for the force range constraint condition is as follows: In the formula, This represents the minimum force. Maximum force; S22, extract the preset reference force from the real-time pressure data. The target construction pile with the largest deviation is identified, and under the constraints of total load balance and force range, the force applied by the jacks of the target construction pile is updated. Each time it is updated, the variance of multiple force data is calculated until the variance is minimized. S23, when the variance of multiple force data is minimized, the variance is compared with a preset variance threshold. If the variance is greater than the preset variance threshold, the process returns to step S22 until the variance is less than or equal to the preset variance threshold. When the variance is less than or equal to the preset variance threshold, the force adjustment of one or more jacks is obtained.

2. The method for controlling the force application of jacks in the underground excavation construction of pile foundations under an existing station, as described in claim 1, is characterized in that... A finite element analysis model is constructed based on the location of the construction piles in the underpass construction area, the load on the existing station, the stiffness of the existing station floor slab, and the geological information of the strata where the construction piles are located, including: Based on the location of the construction piles in the underpass construction area, a three-dimensional model of the existing station and the underpass construction area is constructed; and based on the stiffness of the existing station floor slab and the geological information of the strata where the construction piles are located, the material properties of the three-dimensional model are defined, boundary constraints are applied to the three-dimensional model, and loads are applied to the three-dimensional model based on the load of the existing station, to obtain a finite element analysis model.

3. The method for controlling the force application of jacks in the underground excavation construction of pile foundations under an existing station, as described in claim 1, is characterized in that... Based on the aforementioned finite element analysis model, the stress variation of the construction pile was simulated, and multiple sets of stress variation sample data were obtained, including: S11, Select the current construction pile and adjust the force on the current construction pile multiple times, with each adjustment amount being [amount missing]. or And during each adjustment, the stress changes of other construction piles were recorded, resulting in a set of stress change sample data, among which... To adjust the number of times, The adjustment amount for a single adjustment; S12, take the next construction pile as the current construction pile, and return to step S11 until the stress adjustment of all construction piles is completed, and obtain multiple sets of stress change sample data.

4. The method for controlling the force application of jacks in the underground excavation construction of pile foundations under an existing station, as described in claim 1, is characterized in that... Based on the aforementioned multiple sets of stress variation sample data, a stress relationship model for multiple construction piles is constructed, including: For each set of force variation sample data, a quadratic nonlinear relationship equation is constructed, wherein the mathematical expression of the quadratic nonlinear relationship equation is: In the formula, This represents the stress change of the current construction pile in the current group of stress change sample data. The first sample of force changes in the current group The stress change of other construction piles, For the first The secondary parameters of other construction piles to be estimated. For the first The parameters to be estimated for one of the other construction piles are as follows: For the first The estimated offset parameters of other construction piles; Each set of stress variation sample data is substituted into a quadratic nonlinear relational equation for fitting, yielding a result characterizing the construction pile. Construction pile under stress changes Nonlinear relational equations corresponding to changing conditions; and force relationship models constructed based on multiple nonlinear relational equations.

5. The method for controlling the force application of jacks in the underground excavation construction of pile foundations under an existing station, as described in claim 4, is characterized in that... The nonlinear relationship equation is fitted using the least squares method.

6. The method for controlling the force application of jacks in the underground excavation of pile foundations for tunneling under an existing station, as described in claim 1, is characterized in that... The real-time pressure data is subjected to equilibrium state analysis, including: Extract the pressure data sequence at the current time point from the real-time pressure data. , where subscript All are construction pile serial numbers; Calculate the variance of the pressure data of all jacks at the top of the construction piles in the pressure data series. And calculate the pressure data sequence. Each pressure data point is compared with the preset reference force. The difference between them yields a pressure change data sequence. ; When the variance The variance is greater than a preset variance threshold, or the pressure change data sequence If any pressure change value exceeds a preset threshold, the real-time pressure data is determined to be unstable; otherwise, the real-time pressure data is determined to be stable.

7. The method for controlling the force application of jacks in the underground excavation of pile foundations for tunneling under an existing station, as described in claim 1, is characterized in that... Updating the applied force of the jacks on the target construction pile includes: Get the variance at the last update and current variance And obtain the initial variance before performing the update. ; Based on the variance at the time of the last update The current variance and the initial variance Determine the adjustment amount for the next update. The adjustment amount in the next update The mathematical expression is: In the formula, This is the maximum adjustment amount set for a single operation.

8. The method for controlling the force application of jacks in the underground excavation of pile foundations for tunneling under an existing station, as described in claim 1, is characterized in that... Controlling the force applied by the jacks based on the force adjustment of one or more jacks includes: The force application of the jacks is adjusted sequentially based on closed-loop control, according to the force adjustment of one or more jacks.

9. A jacking force application control system for underground tunneling of existing station foundations, characterized in that, include: The acquisition module is used to acquire the location of the construction piles in the construction area, the load of the existing station, the rigidity of the existing station floor slab, and the geological information of the strata where the construction piles are located; and to acquire the real-time pressure data of the jacks at the top of the construction piles. The simulation module is used to construct a finite element analysis model based on the location of the construction piles in the underpass construction area, the load of the existing station, the rigidity of the existing station floor slab, and the geological information of the strata where the construction piles are located. Based on the finite element analysis model, the module simulates the stress changes of the construction piles and obtains multiple sets of stress change sample data. Each set of stress change sample data includes the stress changes of other construction piles when the stress of one construction pile deviates from the set value to a certain extent. The relational model construction module is used to construct a force relational model for multiple construction piles based on the multiple sets of force change sample data. The force relational model characterizes the changes in the force of other construction piles when the force of different construction piles deviates from the set value to different degrees. The analysis and control module is used to perform balance state analysis on the real-time pressure data, and when the real-time pressure data is in an unbalanced state, to plan the force adjustment amount based on the real-time pressure data and the force relationship model, thereby obtaining the force adjustment amount of one or more jacks; and to control the force application of the jacks based on the force adjustment amount of the one or more jacks, including: S21, constructing an objective function with the goal of minimizing the variance of the pressure data, and configuring total load balance constraints and force range constraints to limit the force on a single construction pile; wherein, the mathematical expression of the objective function is: In the formula, These represent the forces exerted on the jacks at the top of the construction pile after the applied force is adjusted; the mathematical expression for the total load balance constraint condition is: In the formula, The total load of existing stations, The deviation tolerance ratio is used; the mathematical expression for the force range constraint condition is as follows: In the formula, This represents the minimum force. Maximum force; S22, extract the preset reference force from the real-time pressure data. The target construction pile with the largest deviation is identified, and under the constraints of total load balance and force range, the force applied by the jacks of the target construction pile is updated. Each time it is updated, the variance of multiple force data is calculated until the variance is minimized. S23, when the variance of multiple force data is minimized, the variance is compared with a preset variance threshold. If the variance is greater than the preset variance threshold, the process returns to step S22 until the variance is less than or equal to the preset variance threshold. When the variance is less than or equal to the preset variance threshold, the force adjustment of one or more jacks is obtained.

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