A method, medium and system for determining critical index of impact of pile foundation construction on surrounding areas

Abstract

The present invention provides a method, medium and system for determining critical indicators of the impact of pile foundation construction on the surrounding area, belonging to the technical field of the impact of pile foundation construction on the surrounding area, including: firstly, obtaining geological and pile foundation data, establishing a three-dimensional geological model and a hydrogeological model, and predicting the impact of pile foundation construction on groundwater level, ground subsidence and building deformation. Next, a mathematical model is established to solve the distribution functions of stress, deformation, vibration and the like, and parameterized fitting is performed according to the on-site monitoring data. Finite element analysis is used to simulate the construction process, and various uncertain factors are comprehensively considered to calculate the critical indicators of stress, deformation, groundwater level change, vibration acceleration, ground subsidence and building deformation. Finally, the critical indicators are compared with engineering specifications and regulatory requirements to determine the final safety threshold. The method makes full use of the three-dimensional model, mathematical model and monitoring data to provide comprehensive risk assessment and control measures for pile foundation construction to ensure construction safety.

Description

Technical Field

[0001] The present invention belongs to the technical field of pile foundation construction's impact on surrounding areas, and in particular, relates to a method, medium and system for determining a critical index of pile foundation construction's impact on surrounding areas. Background Art

[0002] At present, with the continuous acceleration of urbanization, various infrastructure construction projects such as roads, railways, bridges, docks and other projects are increasing. Among them, pile foundation projects are widely used in the foundation construction of various buildings and structures as an important means of foundation treatment. The impact of pile foundation construction on the surrounding environment has been a hot issue of long-term concern, mainly manifested in the changes in soil stress, stratum deformation, groundwater level changes, vibration propagation, ground subsidence and deformation of surrounding buildings caused by the construction process. These impacts may not only lead to safety hazards at the construction site, but also cause serious damage to the surrounding environment and even threaten the normal use of buildings. Therefore, how to effectively evaluate and control the impact of pile foundation construction on the surrounding environment has always been the focus of the industry.

[0003] The existing environmental impact assessment methods for pile foundation construction mainly include the following:

[0004] 1. Empirical evaluation method: Based on common experience, combined with factors such as the geological conditions of the construction area and the surrounding environment, a qualitative or semi-quantitative method is used to evaluate the possible impact of construction. However, this method lacks scientific basis, and the evaluation results are often unreliable and untargeted.

[0005] 2. Simulation analysis method: Establish a numerical analysis model, such as a finite element model, to simulate stress changes, deformation, vibration propagation, etc. during the construction process, and then evaluate the environmental impact. However, the determination of model parameters often relies on a large amount of test data, and it is difficult to fully consider the complexity of actual working conditions.

[0006] 3. On-site monitoring method: Deploy monitoring equipment at the construction site to monitor the changes in parameters such as vibration, settlement, and groundwater level in real time to evaluate the impact of construction. This method can reflect actual working conditions, but it is difficult to predict the long-term impact of construction on the future environment.

[0007] The above methods have their own advantages and disadvantages. They cannot systematically analyze and predict the overall impact of pile foundation construction on the surrounding environment, nor can they establish a scientific and reasonable critical index system, which seriously restricts the smooth progress of engineering construction. Therefore, there is an urgent need for a new method that can comprehensively analyze the environmental impact of pile foundation construction and determine reasonable critical indicators. Summary of the invention

[0008] In view of this, the present invention provides a method, medium and system for determining critical indicators of the impact of pile foundation construction on the surrounding environment, which can solve the technical problems that the prior art cannot systematically analyze and predict the comprehensive impact of pile foundation construction on the surrounding environment, and cannot establish a scientific and reasonable critical indicator system.

[0009] The present invention is achieved in that:

[0010] A first aspect of the present invention provides a method for determining a critical index of the impact of pile foundation construction on the surrounding area, which comprises the following steps:

[0011] S10, obtaining geological data of the construction area and pile foundation data of the construction, wherein the geological data at least includes stratum structure, soil parameters and groundwater level; the pile foundation data at least includes pile diameter, pile length and pile weight;

[0012] S20. Establish a three-dimensional geological model to simulate the geological conditions of the construction area and the surrounding environment; establish a hydrogeological model to predict the impact of pile foundation construction on the groundwater level and analyze the resulting ground subsidence and deformation of surrounding buildings;

[0013] S30, establishing a set of equations for the influence of the pile foundation on the surroundings, including a stress balance equation, a deformation coordination equation, a seepage control equation, a vibration propagation equation, a ground settlement equation, and a building deformation equation;

[0014] S40, analytically solving the equation group to obtain multiple analytical solutions, which are stress distribution function, deformation distribution function, groundwater level change function, vibration propagation function, ground settlement function and building deformation function; and parameterizing the analytical solutions according to the three-dimensional geological model and the hydrogeological model to obtain multiple range groups for representing stress influence range, deformation influence range, groundwater level influence range, vibration influence range, settlement influence range and building deformation influence range;

[0015] S50, using finite element analysis to establish a numerical model of the pile foundation construction process, and simulate stress changes and stratum deformation during the construction process;

[0016] S60, obtaining monitoring data from vibration monitors, settlement observation points, and groundwater level observation wells arranged at multiple key points on the pile foundation construction site, including vibration acceleration, frequency, surface settlement, building inclination angle, and groundwater level change;

[0017] S70, establishing a vibration analysis model for performing vibration analysis and calculating vibration intensity and propagation characteristics during the construction process;

[0018] S80, based on the range group obtained by S40, the numerical model simulation results of S50 and the monitoring data of S60, adopts the Bayesian inference method, comprehensively considers various uncertain factors, and calculates the critical indicators of the impact of pile foundation construction on the surrounding area. These critical indicators include: maximum allowable stress, maximum allowable deformation, maximum allowable groundwater level change, maximum allowable vibration acceleration, maximum allowable ground settlement and maximum allowable building deformation;

[0019] S90, comparing the critical indicators obtained in S80 with engineering specifications and local regulations, determining a final critical indicator threshold range set as the critical indicator of the impact of pile foundation construction on the surrounding area and outputting it.

[0020] Wherein, the specific implementation method of obtaining the geological data of the construction area and the pile foundation data of the construction in step S10 includes: first, it is necessary to obtain the geological information of the construction area, including the stratum structure, soil parameters and groundwater level. The stratum structure can be obtained by geological exploration and other means, wherein the thickness, burial depth, distribution characteristics and the like of the stratum can be used to describe the stratum structure. The soil parameters include mechanical properties such as soil density, water content, permeability coefficient, and compression coefficient, which can be obtained by field sampling tests or indoor tests. The groundwater level can be measured by drilling or laying observation wells. Secondly, the geometric parameters of the construction pile foundation, such as pile diameter, pile length, pile weight, etc., are collected. These parameters directly affect the bearing capacity of the pile foundation and the impact of the construction on the surrounding environment. The pile foundation data can be obtained from engineering design materials or construction records. Finally, the acquired geological data and pile foundation data are sorted and archived, and a geological database is established to lay the foundation for subsequent analysis and modeling.

[0021] The specific implementation method of establishing the three-dimensional geological model and the hydrogeological model in step S20 includes: first, according to the data such as the stratum structure and soil parameters obtained in step S10, a three-dimensional geological model is established by using mathematical methods such as interpolation or fitting, and the model can represent the distribution of geological characteristics in space. Secondly, according to the groundwater level data, a hydrogeological model is established by using the Darcy seepage equation to predict the impact of pile foundation construction on the groundwater level. Finally, the parameters of the established three-dimensional geological model and hydrogeological model are calibrated and verified using field monitoring data to ensure the accuracy and reliability of the model and provide good basic data for subsequent impact analysis.

[0022] The specific implementation method of the step S30 of establishing the equation group of the pile foundation's influence on the surrounding environment includes: first, according to the classical stress theory, a stress balance differential equation group is established to describe the soil stress change caused by the pile foundation construction; second, according to the classical strain theory, a deformation coordination differential equation group is established to describe the soil deformation caused by the pile foundation construction; third, according to the Darcy seepage theory, a differential equation describing the groundwater level change is established; at the same time, according to the classical vibration theory, a differential equation describing the vibration propagation is established; in addition, according to the soil layer compression theory, an equation describing the ground settlement is established; finally, according to the building deformation theory, an equation group describing the building deformation is established. Through the above steps, a series of mathematical models describing the influence of pile foundation construction on the surrounding environment are established, which provides a basis for the subsequent impact analysis and critical index determination.

[0023] The specific implementation of solving the equation group and performing parameterized fitting in step S40 includes: firstly, solving the equation group established in step S30 by an analytical method to obtain stress distribution function, deformation distribution function, groundwater level change function, vibration propagation function, ground settlement function and building deformation function, etc.; secondly, performing parameterized fitting on the above distribution functions according to the three-dimensional geological model and hydrogeological model established in step S20 to obtain a range group for representing the influence range, including stress influence range, deformation influence range, groundwater level influence range, vibration influence range, settlement influence range and building deformation influence range. Through this step, analytical solutions and influence ranges of various influences can be obtained, which provides a basis for subsequent numerical simulation and critical index determination.

[0024] The specific implementation method of the step S50 for establishing the numerical model of the pile foundation construction process includes: first, using the finite element analysis method, a three-dimensional nonlinear finite element model is established to simulate the soil-pile-structure interaction during the pile foundation construction process, taking into account geometric nonlinearity and contact nonlinearity; second, for the soil layer and structural materials, an appropriate constitutive model is selected, such as the Mohr-Coulomb model, the Cam-Clay model, etc., and the material parameters are determined according to the soil parameters obtained in step S10; third, according to the actual engineering situation, the calculation area is meshed to generate a three-dimensional finite element mesh model; finally, appropriate boundary conditions and construction loads are applied to the model, and an implicit or explicit algorithm is used to perform nonlinear dynamic analysis to simulate the stress changes and stratum deformation during the pile foundation construction process. The numerical model established by this step provides support for subsequent impact assessment and critical index determination.

[0025] The specific implementation method of obtaining the construction site monitoring data in step S60 includes: firstly, setting up vibration monitors at key points in the construction area to monitor parameters such as vibration acceleration and vibration frequency in real time during the construction process; secondly, setting up settlement observation points in the construction area and surrounding areas, and using high-precision measurement equipment to monitor the changes in surface settlement and the changes in the inclination angle of the building in real time; thirdly, reasonably setting up groundwater level observation wells in the construction area and its influence range to monitor the changes in groundwater level in real time; finally, regularly collecting various monitoring data recorded by the above monitoring equipment to form a complete on-site monitoring database. The monitoring data obtained through this step provides a reliable basis for subsequent impact analysis and critical indicator determination.

[0026] The specific implementation of the step S70 to establish the vibration analysis model includes: firstly, using the equivalent stiffness-mass-damping model to establish a vibration analysis model that considers soil-structure interaction; secondly, according to the soil layer parameters obtained in step S10, various parameters in the vibration analysis model are determined; finally, the frequency domain analysis method is used to perform frequency response analysis on the established soil-structure interaction model to calculate the vibration acceleration and vibration frequency during the construction process. This vibration analysis model provides an important reference for the subsequent determination of critical indicators.

[0027] Among them, the specific implementation method of determining the critical indicators by using the Bayesian inference method in step S80 includes: firstly, determining the critical impact indicators to be evaluated, including the maximum allowable stress, the maximum allowable deformation, the maximum allowable groundwater level change, the maximum allowable vibration acceleration, the maximum allowable ground settlement and the maximum allowable building deformation; secondly, based on the various analysis results and on-site monitoring data obtained in the above steps, using the Bayesian inference method to conduct a comprehensive analysis and inference of the above critical indicators to fully consider various uncertain factors; finally, determining the final threshold range of each critical indicator to provide a reliable basis for the implementation of the project. Through this step, a variety of analysis methods and data sources can be comprehensively utilized to determine various critical impact indicators of pile foundation construction on the surrounding environment.

[0028] The specific implementation of outputting the critical index result in step S90 includes: firstly, comparing and analyzing the critical indexes determined in step S80 with the relevant engineering specifications and local regulations; secondly, determining the final threshold range set of each critical impact index based on the above comparison results; if the critical index value exceeds the limit required by the specification or regulation, the limit of the specification or regulation is used as the final threshold, otherwise the calculated critical index value is used as the final threshold; finally, the determined threshold range set of each critical index is sorted and output as an important reference for the impact of pile foundation construction on the surrounding environment. This step ensures that the final result of the critical index meets the requirements of relevant specifications and regulations.

[0029] The three-dimensional geological model is specifically represented as follows:

[0030]

[0031] Where G(x,y,z) represents the value of geological characteristics at the spatial point (x,y,z); n is the number of strata; α i is the weight coefficient of the i-th layer; f i (x, y, z) is the geological characteristic function of the i-th layer;

[0032] The hydrogeological model is specifically expressed as follows:

[0033]

[0034] Where h is the water head; K x ,K y ,K z are the permeability coefficients in the x, y, and z directions respectively; S s is the specific water storage rate; t is the time; W is the source and sink term.

[0035] Wherein, the stress balance equation is specifically expressed as:

[0036]

[0037] In the formula, σ xx ,σ yy ,σ zz is the normal stress component; τ xy ,τ yz ,τ zx is the shear stress component; F x ,F y ,F z is the body force component.

[0038] Among them, the deformation coordination equation is specifically expressed as:

[0039]

[0040] In the formula, ε xx ,ε yy ,ε zz is the positive strain component; ε xy ,ε yz ,ε zx is the shear strain component.

[0041] Wherein, the seepage control equation is specifically expressed as:

[0042]

[0043] Where p is the pore pressure; k x ,ky ,k z are the permeabilities in the x, y, and z directions respectively; φ is the porosity; ρ is the fluid density.

[0044] Among them, the vibration propagation equation is specifically expressed as:

[0045]

[0046] Where, u is the displacement vector; c is the wave velocity; is the Laplace operator.

[0047] The ground subsidence equation is specifically expressed as:

[0048]

[0049] Where S is the total settlement; n is the number of soil layers; H i is the thickness of the i-th soil layer; Δe i is the change of void ratio of the i-th soil layer; e 0i is the initial void ratio of the i-th soil layer.

[0050] Among them, the building deformation equation is specifically expressed as:

[0051]

[0052] In the formula, θ x ,θ y is the inclination angle of the building in the x and y directions; ΔS x ,ΔS y is the settlement difference of the building in the x and y directions; L x ,L y is the length of the building in the x and y directions; δ is the total deformation; u, v, w are the displacement components in the x, y, and z directions respectively; ε vol is the volume strain; xy ,γ yz ,γ zx is the shear strain component.

[0053] A second aspect of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores program instructions, and when the program instructions are executed, they are used to execute the above-mentioned method for determining critical indicators of the impact of pile foundation construction on the surrounding area.

[0054] A third aspect of the present invention provides a critical index determination system for the impact of pile foundation construction on the surrounding area, which includes the above-mentioned computer-readable storage medium.

[0055] Compared with the prior art, the method, medium and system for determining critical indicators of the impact of pile foundation construction on the surrounding area provided by the present invention have the following beneficial effects:

[0056] 1. A comprehensive analysis model was established: The method of the present invention adopts a systematic mathematical modeling method to establish a set of equations that describe the various impacts of pile foundation construction on the surrounding environment, including stress balance equations, deformation coordination equations, seepage control equations, vibration propagation equations, ground settlement equations and building deformation equations, etc., which can comprehensively reflect the impact mechanism of construction on the surrounding environment.

[0057] 2. Accurate impact prediction was achieved: Based on the established analysis model, the method of the present invention adopts a method that combines analytical solution and numerical simulation to obtain the distribution function and impact range of various impacts, which can accurately predict the specific impact of construction on the surrounding environment and provide a reliable basis for the determination of critical indicators.

[0058] 3. Comprehensive consideration of uncertainty factors: The method of the present invention adopts the Bayesian inference method, fully considers various uncertainty factors such as geological conditions, construction technology, monitoring data, etc., determines the reliable value range of each critical indicator, and improves the scientificity and reliability of indicator determination.

[0059] 4. Satisfy the requirements of standards and regulations: When determining critical indicators, the method of the present invention compares the calculation results with relevant engineering standards and local regulatory requirements to ensure that the final results meet the requirements of standards and regulations, providing practical technical support for engineering implementation.

[0060] 5. Improved the ability of construction to control the surrounding environment: Through the critical indicators determined by the method of the present invention, the construction unit can take targeted measures to effectively control the adverse effects of pile foundation construction on the surrounding environment, minimize damage to the environment, and provide strong support for urban construction and environmental protection.

[0061] In summary, the method for determining critical indicators of the impact of pile foundation construction on the surrounding environment proposed in the present invention can systematically analyze and predict the various impacts of construction on the surrounding environment, provide a scientific and reasonable technical basis for engineering construction, and solve the technical problems that the existing technology cannot systematically analyze and predict the comprehensive impact of pile foundation construction on the surrounding environment, and cannot establish a scientific and reasonable critical indicator system. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 A flow chart of the method provided by the present invention. DETAILED DESCRIPTION

[0063] In order to make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0064] like Figure 1 As shown, it is a flow chart of a method for determining a critical index of the impact of pile foundation construction on the surrounding provided by the present invention. The method comprises the following steps:

[0065] S10, obtaining geological data of the construction area and pile foundation data of the construction, wherein the geological data at least includes stratum structure, soil parameters and groundwater level; the pile foundation data at least includes pile diameter, pile length and pile weight;

[0066] S20. Establish a three-dimensional geological model to simulate the geological conditions of the construction area and the surrounding environment; establish a hydrogeological model to predict the impact of pile foundation construction on the groundwater level and analyze the resulting ground subsidence and deformation of surrounding buildings;

[0067] S30, establishing a set of equations for the influence of the pile foundation on the surroundings, including a stress balance equation, a deformation coordination equation, a seepage control equation, a vibration propagation equation, a ground settlement equation, and a building deformation equation;

[0068] S40, analytically solving the equation group to obtain multiple analytical solutions, which are stress distribution function, deformation distribution function, groundwater level change function, vibration propagation function, ground settlement function and building deformation function; and parameterizing the analytical solutions according to the three-dimensional geological model and the hydrogeological model to obtain multiple range groups for representing the stress influence range, deformation influence range, groundwater level influence range, vibration influence range, settlement influence range and building deformation influence range;

[0069] S50, using finite element analysis to establish a numerical model of the pile foundation construction process, and simulate stress changes and stratum deformation during the construction process;

[0070] S60, obtaining monitoring data from vibration monitors, settlement observation points, and groundwater level observation wells arranged at multiple key points on the pile foundation construction site, including vibration acceleration, frequency, surface settlement, building inclination angle, and groundwater level change;

[0071] S70, establishing a vibration analysis model for performing vibration analysis and calculating vibration intensity and propagation characteristics during the construction process;

[0072] S80, based on the range group obtained by S40, the numerical model simulation results of S50 and the monitoring data of S60, adopts the Bayesian inference method, comprehensively considers various uncertain factors, and calculates the critical indicators of the impact of pile foundation construction on the surrounding area. These critical indicators include: maximum allowable stress, maximum allowable deformation, maximum allowable groundwater level change, maximum allowable vibration acceleration, maximum allowable ground settlement and maximum allowable building deformation;

[0073] S90, comparing the critical indicators obtained in S80 with engineering specifications and local regulations, determining a final critical indicator threshold range set as the critical indicator of the impact of pile foundation construction on the surrounding area and outputting it.

[0074] The specific implementation methods of the above steps are described in detail below:

[0075] Step S10: Obtain geological data of the construction area and pile foundation data of the construction

[0076] The purpose of this step is to collect the basic data required for pile foundation construction and lay the foundation for subsequent modeling and analysis. It includes the following sub-steps:

[0077] 1) Obtain geological data of the construction area: First, it is necessary to obtain geological information of the construction area, including stratigraphic structure, soil parameters and groundwater level. The stratigraphic structure can be obtained through geological exploration and other methods, among which the thickness, burial depth and distribution characteristics of the stratigraphic layer can be used to describe the stratigraphic structure. Soil parameters include mechanical properties such as soil density, water content, permeability coefficient and compression coefficient, which can be obtained through on-site sampling tests or indoor tests. The groundwater level can be measured by drilling or laying observation wells.

[0078] 2) Obtain pile foundation data: Collect the geometric parameters of the pile foundation, such as pile diameter, pile length, pile weight, etc. These parameters directly affect the bearing capacity of the pile foundation and the impact of the construction on the surrounding environment. Pile foundation data can be obtained from engineering design data or construction records.

[0079] 3) Establish a geological database: organize and archive the acquired geological data and pile foundation data, establish a geological database, and provide basic data support for subsequent modeling and analysis.

[0080] Through the above sub-steps, the geological conditions and pile foundation parameters of the construction area can be fully understood, laying the foundation for subsequent analysis and modeling. It is particularly important to note that the accuracy and completeness of geological data directly affect the reliability of the analysis results, so it is necessary to pay attention to on-site investigation and data collection.

[0081] Step S20: Establishing a 3D geological model and a hydrogeological model

[0082] The purpose of this step is to construct a three-dimensional geological model and hydrogeological model of the construction area to simulate geological conditions and groundwater changes, and provide a basis for subsequent impact analysis. It includes the following sub-steps:

[0083] 1) Establishing a three-dimensional geological model: Based on the data such as the stratum structure and soil parameters obtained in step S10, a three-dimensional geological model G (x, y, z) is established using mathematical methods such as interpolation or fitting. The model can be expressed as:

[0084]

[0085] Where G(x,y,z) represents the value of geological characteristics at the spatial point (x,y,z); n is the number of strata; α i is the weight coefficient of the i-th layer; f i (x, y, z) is the geological characteristic function of the i-th layer. Through this model, the three-dimensional geological conditions of the construction area can be described.

[0086] 2) Establish a hydrogeological model: Based on the groundwater level data, establish a hydrogeological model to predict the impact of pile foundation construction on the groundwater level. The Darcy seepage equation can be used to establish a hydrogeological model:

[0087]

[0088] Where, h is the water head; K x ,K y ,K z are the permeability coefficients in the x, y, and z directions respectively; S s is the specific water storage rate; t is time; W is the source and sink term. Through this model, the change of groundwater level can be predicted.

[0089] 3) Parameter calibration and verification: Use field monitoring data to calibrate and verify the parameters of the established three-dimensional geological model and hydrogeological model to ensure the accuracy and reliability of the model and provide good basic data for subsequent impact analysis.

[0090] Through the above sub-steps, a mathematical model reflecting the actual geological conditions and groundwater changes in the construction area can be established to provide support for subsequent impact analysis.

[0091] Step S30: Establishing the equation group of the pile foundation's influence on the surrounding area

[0092] The purpose of this step is to establish a mathematical model of the various impact mechanisms of pile foundation construction on the surrounding environment, providing a basis for subsequent impact assessment and critical index determination. It specifically includes the following sub-steps:

[0093] 1) Establish stress balance equation: According to the classical stress theory, establish a group of stress balance differential equations to describe the stress changes in the soil layer caused by pile foundation construction:

[0094]

[0095] Among them, σ xx ,σ yy ,σ zz is the normal stress component; τ xy ,τ yz ,τ zx is the shear stress component; F x ,F y ,F x is the body force component.

[0096] 2) Establish deformation coordination equation: According to the classical strain theory, establish a set of deformation coordination differential equations to describe the soil deformation caused by pile foundation construction:

[0097]

[0098] Among them, ε xx ,ε yy ,ε zz is the positive strain component; ε xy ,ε yz ,ε zx is the shear strain component.

[0099] 3) Establish the seepage control equation: According to Darcy seepage theory, establish the differential equation describing the change of groundwater level:

[0100]

[0101] Where, p is the pore pressure; k x ,k y ,k z are the permeabilities in the x, y, and z directions respectively; φ is the porosity; ρ is the fluid density.

[0102] 4) Establish vibration propagation equation: According to the classical vibration theory, establish the differential equation describing vibration propagation:

[0103]

[0104] Among them, u is the displacement vector; c is the wave speed; is the Laplace operator.

[0105] 5) Establish the ground subsidence equation: According to the soil compression theory, establish the equation describing the ground subsidence:

[0106]

[0107] Where S is the total settlement; n is the number of soil layers; H i is the thickness of the i-th soil layer; Δe i is the change of void ratio of the i-th soil layer; e 0i is the initial void ratio of the i-th soil layer.

[0108] 6) Establish building deformation equation: According to the building deformation theory, establish the equation group describing the building deformation:

[0109]

[0110] Among them, θ x ,θ y is the inclination angle of the building in the x and y directions; ΔS x ,ΔS y is the settlement difference of the building in the x and y directions; L x ,L y is the length of the building in the x and y directions; δ is the total deformation; u, v, w are the displacement components in the x, y, and z directions respectively; ε vol is the volume strain; xy ,γ yz ,γ zx is the shear strain component.

[0111] Through the above sub-steps, a series of mathematical models describing the impact of pile foundation construction on the surrounding environment were established, which provided a basis for the subsequent impact analysis and critical index determination. These models cover various aspects such as stress change, deformation, groundwater level change, vibration propagation, ground subsidence and building deformation, reflecting the complex impact mechanism of pile foundation construction on the surrounding environment.

[0112] Step S40: Solving the equations and performing parameterized fitting

[0113] The purpose of this step is to solve the equations established in step S30, obtain the distribution functions of various impacts, and perform parameterized fitting to provide a basis for subsequent impact assessment and critical index determination. It specifically includes the following sub-steps:

[0114] 1) Solving the equations: Solve the equations established in step S30 using an analytical method to obtain the following distribution functions: stress distribution function σ(x, y, z), deformation distribution function ε(x, y, z), groundwater level change function h(x, y, z, t), vibration propagation function u(x, y, z, t), ground settlement function S(x, y) and building deformation function θ x (x,y),θ y (x,y),δ(x,y,z),ε vol (x,y,z),γ xy(x,y,z),γ yz (x,y,z),γ zx (x,y,z).

[0115] 2) Parameterized fitting: According to the three-dimensional geological model and hydrogeological model established in step S20, parameterized fitting is performed on the above-mentioned various distribution functions to obtain a range group for representing the influence range, including: stress influence range R σ 、Deformation influence range R ε 、The influence range of groundwater level R h 、Vibration influence range R u 、Subsidence influence range R S and the building deformation influence range R θ ,R δ , R γ .

[0116] Through the above sub-steps, the analytical solutions and influence ranges of various influences can be obtained, which provides a basis for subsequent numerical simulation and critical index determination. In this process, it is necessary to comprehensively consider the influence of geological conditions and pile foundation parameters on the influence distribution to ensure that the fitting results can accurately reflect the actual situation.

[0117] Step S50: Establishing a numerical model of the pile foundation construction process

[0118] The purpose of this step is to establish a numerical model to simulate the stress changes and ground deformation during pile foundation construction, and to provide support for subsequent impact assessment. It includes the following sub-steps:

[0119] 1) Establish a numerical model using the finite element method: Use the finite element analysis method to establish a three-dimensional nonlinear finite element model to simulate the soil-pile-structure interaction during pile foundation construction, taking into account geometric nonlinearity and contact nonlinearity.

[0120] The finite element equations are as follows:

[0121]

[0122] Where, [K({u})] = [K e ]+[K g ({u})]+[K c ({u})]

[0123] {R({u})}=∫ V [B] T {σ({ε})}dV

[0124] {ε}=[B]{u}

[0125] {σ}=[D]{ε}+{σ0}

[0126] Where [M] is the mass matrix, [C] is the damping matrix, and [K({u})] is the nonlinear stiffness matrix (including the elastic stiffness [K e ], geometric nonlinear stiffness [K g ({u})] and contact nonlinear stiffness [K c ({u})]),{u}, are displacement, velocity and acceleration vectors respectively, {F(t)} is the time-varying external force vector, {R({u})} is the nonlinear internal force vector; [B] is the strain-displacement matrix; {σ} is the stress vector; {ε} is the strain vector; [D] is the elasticity matrix; {σ0} is the initial stress vector; V is the structural volume.

[0127] 2) Determine the material model and parameters: For the soil layer and structural materials, select appropriate constitutive models, such as the Mohr-Coulomb model, the Cam-Clay model, etc., and determine the material parameters according to the soil parameters obtained in step S10. At the same time, it is also necessary to determine parameters such as the friction characteristics of the contact surface.

[0128] 3) Establishing computational grid: According to the actual engineering situation, the computational area is meshed to generate a three-dimensional finite element mesh model. The meshing should ensure the computational accuracy as much as possible while considering the computational efficiency.

[0129] 4) Apply boundary conditions and loads: Apply appropriate boundary conditions to the model, such as constraint conditions of the base, free boundary conditions of the side, etc. At the same time, according to the construction process, apply corresponding loads to the model, such as pile foundation installation loads, construction vibration loads, etc.

[0130] 5) Perform nonlinear dynamic analysis: Use implicit or explicit algorithms to perform nonlinear dynamic analysis on the established finite element model to simulate the stress changes and ground deformation during pile foundation construction.

[0131] Through the above sub-steps, a numerical model that can reflect the soil-pile-structure interaction during pile foundation construction can be established to provide support for subsequent impact assessment and critical index determination. It should be noted that the accuracy and reliability of the numerical model directly affect the accuracy of the analysis results, so the model parameters need to be calibrated and verified.

[0132] Step S60: Obtaining construction site monitoring data

[0133] The purpose of this step is to deploy monitoring equipment at the actual construction site to obtain monitoring data on parameters such as vibration, settlement and groundwater level changes, so as to provide a basis for subsequent impact analysis and critical index determination. It includes the following sub-steps:

[0134] 1) Install vibration monitors: Install vibration monitors at key points in the construction area to monitor parameters such as vibration acceleration and vibration frequency during the construction process in real time.

[0135] 2) Set up settlement observation points: Set up settlement observation points in the construction area and surrounding areas, and use high-precision measuring equipment to monitor the changes in surface settlement and the changes in the inclination angle of the building in real time.

[0136] 3) Lay out groundwater level observation wells: Reasonably lay out groundwater level observation wells in the construction area and its impact range to monitor the changes in groundwater level in real time.

[0137] 4) Collect monitoring data: Regularly collect monitoring data such as vibration acceleration, vibration frequency, surface settlement, building inclination angle and groundwater level changes recorded by the above-mentioned monitoring equipment to form a complete on-site monitoring database.

[0138] Through the above sub-steps, monitoring data reflecting the actual changes of various influencing parameters during the construction process can be obtained, providing a reliable basis for subsequent impact analysis and critical index determination. It should be noted that the layout of monitoring points should be reasonable and able to fully reflect the impact of construction on the surrounding environment.

[0139] Step S70: Establishing a vibration analysis model

[0140] The purpose of this step is to establish a vibration analysis model that takes into account soil-structure interaction, which is used to analyze the vibration characteristics during construction and provide support for the subsequent determination of critical indicators. It includes the following sub-steps:

[0141] 1) Establish soil-structure interaction model: Use the equivalent stiffness-mass-damping model to establish a vibration analysis model that considers soil-structure interaction:

[0142]

[0143] in,

[0144]

[0145] [C r ]=ρ s V s A0[N(0)] T [N(0)]

[0146]

[0147] Among them, [M s ],[C s ],[K s ] is the mass, damping and stiffness matrix of the structure; [Mg ],[C g ],[K g ] is the mass, damping and stiffness matrix of the foundation; [C r ] is the radiation damping matrix; {u}, are the displacement, velocity and acceleration vectors of the structure respectively; {F(t)} is the external excitation force; {F g (t)} is the earthquake excitation force; ρ g is soil density; A g is the foundation area; H is the foundation depth; [N(z)] is the shape function matrix; [c(z)] is the soil damping matrix; [B(z)] is the strain displacement matrix; [D(z)] is the soil elastic matrix; ρ s is the structural density; V s is the shear wave velocity; A0 is the basic contact area; is the ground acceleration vector.

[0148] 2) Determine model parameters: According to the soil layer parameters obtained in step S10, such as soil density, shear wave velocity, etc., determine the various parameters in the above model, such as ρ g ,A g ,H,[c(z)],[D(z)], etc.

[0149] 3) Conduct frequency response analysis: Use frequency domain analysis method to conduct frequency response analysis on the established soil-structure interaction model, calculate the vibration acceleration and vibration frequency during the construction process, and provide a basis for subsequent impact assessment.

[0150] Through the above sub-steps, a vibration analysis model considering soil-structure interaction can be established, and the vibration characteristics during construction can be calculated, which provides an important reference for the subsequent determination of critical indicators.

[0151] Step S80: Determine critical index using Bayesian inference method

[0152] The purpose of this step is to comprehensively utilize the various information obtained in the previous steps and use the Bayesian inference method to determine the critical impact index of pile foundation construction on the surrounding environment. It specifically includes the following sub-steps:

[0153] 1) Determine the impact indicators to be evaluated: Based on the above analysis, determine the critical impact indicators that need to be evaluated, including: maximum allowable stress σ c , maximum allowable deformation ε c , Maximum allowable groundwater level change h c , Maximum allowable vibration acceleration a c , Maximum allowable ground settlement S c and the maximum allowable building deformation θ c ,δ c ,εvol,v ,γ c wait.

[0154] 2) Using Bayesian inference method for analysis: Based on the impact range group obtained in step S40, the numerical simulation results in step S50, and the on-site monitoring data in step S60, the Bayesian inference method is used to conduct a comprehensive analysis and inference on the above critical indicators. The Bayesian inference method can combine the prior probability distribution and sample data to obtain the posterior probability distribution of each critical indicator, thereby determining its final critical value.

[0155] 3) Consider uncertainty factors: In the process of Bayesian inference, various uncertainty factors such as geological conditions, construction technology, and monitoring data need to be fully considered to ensure the reliability of critical indicator evaluation.

[0156] Through the above sub-steps, various analysis methods and data sources can be used to comprehensively determine the various critical impact indicators of pile foundation construction on the surrounding environment. These critical indicators provide an important basis for subsequent engineering design and construction control.

[0157] Step S90: Output critical index results

[0158] The purpose of this step is to compare the critical indicators obtained in the previous steps with the engineering specifications and local regulatory requirements, determine the final critical indicator threshold, and output the results. It specifically includes the following sub-steps:

[0159] 1) Compare with the requirements of the specifications and regulations: Compare the critical indicators determined in step S80, such as the maximum allowable stress σ c , maximum allowable deformation ε c , Maximum allowable groundwater level change h c , Maximum allowable vibration acceleration a c , Maximum allowable ground settlement S c and the maximum allowable building deformation θ c ,δ c ,ε vol,v ,γ c Etc., and compare and analyze with relevant engineering specifications and local regulatory requirements.

[0160] 2) Determine the final critical indicator threshold: Based on the above comparison results, determine the final threshold range set of each critical impact indicator. If the critical indicator value exceeds the limit required by the specification or regulation, the limit of the specification or regulation should be used as the final threshold; if the critical indicator value is lower than the specification or regulation, the calculated critical indicator value can be used as the final threshold.

[0161] 3) Output critical indicator results: The determined threshold ranges of various critical indicators are collected and output as an important reference for the impact of pile foundation construction on the surrounding environment. At the same time, relevant analysis processes and bases should also be attached to provide support for subsequent engineering design and construction control.

[0162] Through the above sub-steps, the results of the above analysis can be compared with the current specifications and regulatory requirements to determine the final threshold range of each critical indicator, providing a reliable basis for project implementation.

[0163] Below is a description of the derivation process of each analytical solution

[0164] 1. Stress distribution function (Boussinesq solution)

[0165] Step 1: Establish the governing equations

[0166]

[0167] Step 2: Introducing the stress function

[0168]

[0169] Step 3: Establish the governing equation of the stress function

[0170]

[0171] Step 4: Solve for the stress function

[0172] in

[0173] Step 5: Calculate stress components

[0174]

[0175] 2. Deformation distribution function

[0176] Step 1: Establish the stress-strain relationship

[0177]

[0178] Step 2: Calculate strain

[0179] Substituting the stress components of the Boussinesq solution, we obtain:

[0180]

[0181] Step 3: Integrate to get the displacement

[0182]

[0183] Apply boundary conditions ur (r=0)=0 and u z (z=∞)=0, we get C1=C2=0, and finally we get:

[0184]

[0185] 3. Groundwater level change function (Theis solution)

[0186] Step 1: Establish the governing equations

[0187]

[0188] Step 2: Apply Laplace Transform

[0189]

[0190] Step 3: Solve the ordinary differential equation

[0191]

[0192] Step 4: Apply boundary conditions

[0193] Consider the boundary conditions of the pumping well: When r→0

[0194] get:

[0195] therefore,

[0196] Step 5: Apply the Inverse Laplace Transform in Define the well function Finally, we get the Theis solution:

[0197] 4. Vibration propagation function

[0198] Step 1: Establish the governing equations

[0199]

[0200] Step 2: Assume the solution is of the form

[0201] u(x,t)=f(x-ct)+g(x+ct)

[0202] Step 3: Verify the solution

[0203]

[0204] Substituting it into the original equation, we can verify that the assumed solution satisfies the equation.

[0205] Step 4: Determine functions f and g

[0206] According to the initial condition: u(x,0)=φ(x), We get: f(x)+g(x)=φ(x), -cf′(x)+cg′(x)=ψ(x) Solving this system of equations, we get:

[0207]

[0208] 5. Land subsidence function (Terzaghi solution)

[0209] Step 1: Establish the governing equations

[0210]

[0211] Step 2: Non-dimensionalization

[0212]

[0213] This gives the dimensionless equation:

[0214] Step 3: Separate variables

[0215] U(Z,T v )=φ(Z)ψ(T v )

[0216] Substituting into the equation, we get:

[0217] Step 4: Solve the ordinary differential equation

[0218]

[0219] φ(Z)=B sin(λZ)+C cos(λZ)

[0220] Step 5: Apply boundary and initial conditions

[0221] Boundary conditions: U(0,T v )=U(1,T v )=0

[0222] Initial condition: U(Z,0)=1

[0223] get: φ n (Z) = sin(λ n Z)

[0224] Step 6: Superposition to get the final solution

[0225]

[0226] Applying the initial conditions, we get Finally, we get the Terzaghi solution:

[0227]

[0228] 6. Building deformation function

[0229] Step 1: Establish the governing equations

[0230]

[0231] Step 2: Determine the load conditions

[0232] q(x)=Pδ(xL / 2)

[0233] Step 3: Integrate the Equation

[0234]

[0235]

[0236] Where [x] + =max(0,x)

[0237] Step 4: Apply boundary conditions

[0238] w(0)=w(L)=0

[0239]

[0240] Step 5: Get the final solution

[0241] After solving for the constants, we obtain the final expression for the deflection:

[0242]

[0243] Here is an explanation of where each variable comes from:

[0244] 1. 3D geological model:

[0245]

[0246] Variable sources and acquisition methods: G (x, y, z): obtained through geological survey and laboratory testing; n: obtained from geological survey reports; α i : Determined through statistical analysis and expert experience; f i (x,y,z): Based on drilling data, geophysical survey results and laboratory test data.

[0247] 2. Hydrogeological model:

[0248]

[0249] Variable sources and acquisition methods: h: obtained through water level observation well measurement; K x ,K y ,K z : Determined by on-site pumping test or indoor penetration test; S s : Determined by on-site water pressure test or indoor consolidation test; t: time parameter, determined according to the observation period; W: determined by water balance analysis or on-site monitoring.

[0250] 3. Stress balance equation:

[0251]

[0252] Variable source and acquisition method: σ xx ,σ yy ,σ zz : obtained through field stress testing (such as hydraulic fracturing) or numerical simulation; τ xy ,τ yz ,τ zx : obtained through triaxial shear test or numerical simulation; F x ,F y ,F z : Calculated based on the gravitational field and other external forces.

[0253] 4. Deformation coordination equation:

[0254]

[0255] Variable source and acquisition method: ε xx ,ε yy ,ε zz : measured by strain gauge or obtained by numerical differentiation of displacement field; ε xy ,ε yz ,ε zx : Measured by strain gauge or obtained by numerical differentiation of displacement field.

[0256] 5. Seepage control equation:

[0257]

[0258] Variable sources and acquisition methods: p: obtained through pore water pressure meter measurement; k x ,k y ,k z : Determined by on-site penetration test or indoor penetration test; φ: Determined by indoor soil physical property test; ρ: Determined by density meter or sampling.

[0259] 6. Vibration propagation equation:

[0260]

[0261] Sources and acquisition methods of variables: u: obtained by measuring with an accelerometer or displacement sensor; c: obtained by on-site wave velocity test (such as shear wave velocity test); t: time parameter, determined according to the monitoring period.

[0262] 7. Land subsidence equation:

[0263]

[0264] Variable sources and acquisition methods: S: obtained through leveling or settlement observation measurement; n: obtained from geological survey reports; H i : obtained from drilling data or geological profile; Δe i : Determined by indoor consolidation test or on-site compression test; e 0i :Determined through indoor soil physical properties test.

[0265] 8. Building deformation equation:

[0266]

[0267] Variable source and acquisition method: θ x ,θ y : Calculated; ΔS x ,ΔS y : Measured using a precision level or total station; L x ,L y : obtained from building design drawings or on-site measurements; u, v, w: measured using displacement sensors or GPS monitoring systems; δ, ε vol ,γ xy ,γ yz ,γ zx : Calculated.

[0268] 9. Numerical model of pile foundation construction process:

[0269]

[0270] [K({u})]=[K e ]+[K g ({u})]+[K c ({u})]

[0271] {R({u})}=∫ V [B] T {σ({ε})}dV

[0272] {ε}=[B]{u}

[0273] {σ}=[D]{ε}+{σ0}

[0274] Sources and acquisition methods of variables: [M]: Calculated based on the density distribution of the structure and soil, the density is obtained through laboratory tests or on-site tests; [C]: Through theoretical calculations or experimental determinations, Rayleigh damping or modal damping can be used for estimation; [K({u})]: Automatically generated by finite element analysis software, based on material properties and geometric information; [K e ]: Calculated based on the elastic modulus of the material, which is obtained through laboratory testing or on-site testing; [K g ({u})],[K c ({u})]: Updated during iterative calculation; {u}, Obtained by solving differential equations using numerical integration methods; {F(t)}: determined based on construction loads and environmental loads, and can be obtained through on-site monitoring or theoretical calculations; [B]: automatically generated based on finite element discretization and interpolation functions; {σ}, {ε}: obtained through numerical calculations; [D]: determined based on the constitutive relationship of the material and obtained through laboratory tests; {σ0}: estimated through on-site in-situ stress testing or theoretical calculations; V: obtained from the structural design drawings.

[0275] 10. Vibration analysis model:

[0276]

[0277] [C r ]=ρ s V s A0[N(0)] T [N(0)]

[0278]

[0279] Variable source and acquisition method: [M s ],[C s ],[K s ]: Calculated based on structural design parameters and can be automatically generated by finite element software; [M g ],[C g ],[K g ]: calculated by numerical integration; [C r ]: Calculated based on radiation damping theory; {u}, Obtained by numerically solving the vibration equation; {F(t)}: Determined according to the construction process and equipment parameters, and can be obtained through field testing; {F g (t)}: calculated based on ground motion parameters, which can be obtained from the Earthquake Bureau or obtained through site seismic response analysis; ρ g : Determined by geotechnical test; A g: obtained from foundation design drawings; H: obtained from geological survey reports or drilling data; [N(z)]: automatically generated based on finite element discretization; [c(z)]: estimated through on-site dynamic tests or empirical formulas; [B(z)]: automatically generated based on finite element discretization; [D(z)]: determined based on the stress-strain relationship of the soil and obtained through laboratory tests; ρ s : Obtained from the structural material property table; V s : obtained through on-site wave velocity test (such as transverse wave velocity test); A0: obtained from basic design drawings; The acceleration time history is measured by a seismic recorder or artificially synthesized.

[0280] It should be noted that the multiple key points usually include the following positions and can be determined in the following ways:

[0281] a) Around the pile foundation: evenly arrange monitoring points around the pile foundation at a certain radius (such as 5 meters, 10 meters, 20 meters, etc.).

[0282] b) Adjacent buildings: Select several buildings closest to the pile foundation and set up monitoring points on their foundations or walls.

[0283] c) Intersection of underground pipelines: Identify important underground pipelines in the construction area and set up monitoring points at their intersections with the pile foundation construction area.

[0284] d) Geologically weak zones: Based on the geological survey report, monitoring points shall be set up in the identified geologically weak zones.

[0285] e) Numerical simulation prediction: Through preliminary numerical simulation, key areas such as stress concentration areas and maximum deformation areas are found, and monitoring points are set in these areas.

[0286] f) Expert evaluation: Invite experts in ground and pile foundation engineering to conduct on-site surveys and determine key monitoring locations based on experience.

[0287] The determination method can be based on comprehensive consideration of the above factors and final determination based on specific project characteristics and site conditions.

[0288] 2. Numerical model simulates stress changes and ground deformation during construction:

[0289] The numerical model can simulate the stress changes and ground deformation during the construction process through the following steps:

[0290] a) Establish geometric model: According to geological survey data and pile foundation design parameters, establish a three-dimensional geometric model, including strata, pile foundations and surrounding buildings.

[0291] b) Define material properties: Assign corresponding material properties to each part of the model, such as elastic modulus, Poisson's ratio, density, strength parameters, etc.

[0292] c) Set boundary conditions: define the boundary conditions of the model, such as bottom fixation, side constraints, etc.

[0293] d) Construction process simulation:

[0294] - Calculation of initial stress field: simulate the stress state of the original formation.

[0295] -Excavation simulation: Remove the soil elements at the pile location and simulate the hole-forming process.

[0296] -Pile construction: Add pile units to simulate the concrete pouring process.

[0297] - Load application: Simulate pile top load and surrounding building load.

[0298] e) Solution: Use the finite element method to solve the stress field and displacement field at each construction stage.

[0299] f) Post-processing: Analyze the stress distribution and deformation at each stage, and extract the stress and deformation data of key points.

[0300] g) Time effect: Long-term deformation analysis is performed by considering time-related effects such as soil consolidation.

[0301] h) Parameter sensitivity analysis: By changing the input parameters, analyze the impact of different parameters on the results.

[0302] In this way, the numerical model can fully simulate the stress changes and ground deformation during pile foundation construction, providing an important basis for determining critical indicators.

[0303] A second aspect of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores program instructions, and when the program instructions are executed, they are used to execute the above-mentioned method for determining critical indicators of the impact of pile foundation construction on the surrounding area.

[0304] A third aspect of the present invention provides a critical index determination system for the impact of pile foundation construction on the surrounding area, which includes the above-mentioned computer-readable storage medium.

[0305] Specifically, the principle of the present invention is:

[0306] First, in view of the various environmental impacts that may be caused during the pile foundation construction process, the present invention establishes mathematical models covering stress, deformation, groundwater level, vibration, settlement and building deformation. These models include stress balance equations, deformation coordination equations, seepage control equations, vibration propagation equations, ground settlement equations and building deformation equations, which can fully describe the impact mechanism of construction on the surrounding environment. By solving these equations, the distribution functions of various impacts can be obtained, laying the foundation for subsequent impact prediction and critical index determination.

[0307] Secondly, in order to improve the accuracy of impact prediction, the method of the present invention adopts a method combining analytical solution and numerical simulation. First, the distribution functions of various impacts are obtained by analytical solution, and then these distribution functions are parameterized and fitted according to the three-dimensional geological model and hydrogeological model established in step S20 to obtain a mathematical model for representing the impact range. At the same time, the present invention also establishes a nonlinear finite element numerical model of the pile foundation construction process, which can more accurately simulate the stress changes and stratum deformation during the construction process. By comparing and verifying the numerical simulation results with the monitoring data, the reliability of the impact prediction is further improved.

[0308] Thirdly, in view of the fact that the pile foundation construction environment involves many uncertain factors, such as geological conditions, construction technology, monitoring data, etc., the present invention uses the Bayesian inference method to conduct a comprehensive analysis and inference of critical indicators. The Bayesian inference method can combine the prior probability distribution and sample data to obtain the reliable value range of each critical indicator under the premise of fully considering various uncertainties. This can not only improve the scientific nature of the determination of critical indicators, but also better reflect the actual engineering situation.

[0309] Finally, to ensure the rationality and operability of the critical index, the present invention compares and analyzes the calculation results with relevant engineering specifications and local regulatory requirements when determining the final index value. Only when the calculated critical index value meets the specifications and regulatory requirements is it determined as the final index threshold. This not only ensures the rationality of the index, but also ensures the feasibility of engineering implementation.

[0310] In order to better understand and implement the present invention, an embodiment of a specific application scenario of the present invention is provided below: a large-scale urban rail transit project needs to carry out pile foundation construction in the urban area. The surrounding environment of the construction area is relatively complex, with multiple high-rise buildings, large commercial facilities, and underground pipe networks, etc. In order to ensure that the pile foundation construction process will not cause serious adverse effects on the surrounding environment, the construction unit decides to use the critical index determination method of the impact of pile foundation construction on the surrounding environment proposed in the present invention for detailed analysis.

[0311] First, in step S10, the construction unit carried out comprehensive geological exploration and on-site investigation. Through drilling and sampling tests, data such as the stratum structure, soil parameters and groundwater level in the construction area were obtained. The stratum structure can be summarized as follows: 0-5m is plain fill, 5-15m is sub-clay, 15-25m is silty clay, 25-35m is coarse sand layer, and below 35m is bedrock. Soil parameters include: the density of plain fill is 1.8g / cm 3 , water content is 18%, compression coefficient is 0.25MPa^-1; density of sub-clay is 2.0g / cm 3 , water content is 25%, compression coefficient is 0.18MPa^-1; density of silty clay is 2.05g / cm 3 , the water content is 22%, the compression coefficient is 0.15MPa^-1; the density of the coarse sand layer is 2.1g / cm 3 , the permeability coefficient is 5×10^-4m / s. The groundwater level is about 8m deep. At the same time, the construction plan shows that reinforced concrete piles with a diameter of 1.2m and a length of 25m are planned to be used, and the average weight of the piles is 50kN. The collection of the above data laid the foundation for subsequent analysis and modeling.

[0312] Secondly, in step S20, the construction unit establishes a three-dimensional geological model and a hydrogeological model of the construction area. The three-dimensional geological model is constructed using an interpolation method and can be expressed as:

[0313]

[0314] Among them, G(x,y,z) represents the value of geological characteristics at the spatial point (x,y,z); α1=0.18, α2=0.25, α3=0.32, α4=0.25 are the weight coefficients of the four strata respectively; f1(x,y,z), f2(x,y,z), f3(x,y,z), f4(x,y,z) are the geological characteristic functions of plain fill, sub-clay, silty clay and coarse sand layer respectively. The hydrogeological model is established using the Darcy seepage equation, and the main parameters include: permeability coefficient K x =K y =5×10 -7 m / s,K z =2×10 -7 m / s, specific water storage rate S s =1×10 -6 1 / m, initial water head h0=-8m. Through these two models, the geological conditions and groundwater conditions of the area can be better simulated.

[0315] Next, in step S30, the construction unit established a set of equations describing the impact of pile foundation construction on the surrounding environment. The stress balance equations are as follows:

[0316]

[0317] The deformation coordination equations are as follows:

[0318]

[0319] The seepage control equation is:

[0320]

[0321] The vibration propagation equation is:

[0322]

[0323] The ground subsidence equation is:

[0324]

[0325] The building deformation equations are:

[0326]

[0327] These equations comprehensively describe the various environmental impacts that may be caused by pile foundation construction, providing a basis for subsequent analysis and evaluation.

[0328] In step S40, the construction unit first solves the above equations analytically and obtains the distribution functions of various influences. For example, the stress distribution function σ(x, y, z), the deformation distribution function ε(x, y, z), the groundwater level change function h(x, y, z, t), the vibration propagation function u(x, y, z, t), the ground settlement function S(x, y) and the building deformation function θ x (x,y),θ y (x,y),δ(x,y,z),ε vol (x,y,z),γ xy (x,y,z),γ yz (x,y,z),γ zx (x,y,z) etc.

[0329] Next, the construction unit performs parameterized fitting on these distribution functions based on the three-dimensional geological model and hydrogeological model established in step S20, and obtains a mathematical model for representing various influence ranges. σ =25m, deformation influence range R ε =20m, groundwater level influence range R h =15m, vibration impact range R u =50m, settlement impact range R S = 10m, and the building deformation influence range R θ=5m,R δ =8m, R γ =4m. These impact ranges provide important basis for the subsequent determination of critical indicators.

[0330] In step S50, the construction company established a three-dimensional nonlinear finite element model to simulate the soil-pile-structure interaction during the pile foundation construction process. The finite element equations are as follows:

[0331]

[0332] Where [M] is the mass matrix, [C] is the damping matrix, and [K({u})] is the nonlinear stiffness matrix (including the elastic stiffness [K e ], geometric nonlinear stiffness [K g ({u})] and contact nonlinear stiffness [K c ({u})]),{u}, are displacement, velocity and acceleration vectors, respectively; {F(t)} is the time-varying external force vector; and {R({u})} is the nonlinear internal force vector. In this model, the construction unit uses the Mohr-Coulomb model to describe the constitutive relationship of the soil layer, and determines the relevant parameters based on the soil parameters obtained in step S10. By analyzing this finite element model, the stress changes and stratum deformation during the construction process can be predicted more accurately.

[0333] In step S60, the construction unit set up multiple vibration monitoring points, settlement observation points and groundwater level observation wells at the construction site. After a month of monitoring, the following data were obtained:

[0334] The peak acceleration of vibration monitoring point 1 is 0.15m / s 2 , the vibration frequency is 15Hz; the peak acceleration of vibration monitoring point 2 is 0.18m / s 2 , the vibration frequency is 18Hz.

[0335] The maximum settlement of settlement observation point 1 is 12mm, and the maximum settlement of observation point 2 is 15mm; the maximum inclination angle of building A is 1 / 800, and the maximum inclination angle of building B is 1 / 600.

[0336] The maximum water level drop of groundwater level observation well 1 is 0.6m, and the maximum water level drop of observation well 2 is 0.8m.

[0337] These monitoring data provide important basis for subsequent analysis and evaluation.

[0338] In step S70, the construction company established a vibration analysis model considering soil-structure interaction:

[0339]

[0340] According to the soil layer parameters obtained in step S10, the mass, damping and stiffness parameters in the model are determined. Through the frequency response analysis of the model, the vibration characteristics during the construction process are obtained, which provides a basis for evaluating the vibration impact.

[0341] Finally, in step S80, the construction unit comprehensively utilizes the analysis results obtained in the previous steps and uses the Bayesian inference method to determine the critical influencing index of pile foundation construction.

[0342] First, critical indicators that need to be evaluated were identified, including:

[0343] Maximum allowable stress σ c =0.8MPa

[0344] Maximum allowable deformation ε c =0.005

[0345] Maximum allowable groundwater level change h c =1.0m

[0346] Maximum allowable vibration acceleration a c =0.2m / s 2

[0347] Maximum allowable ground settlement S c =20mm

[0348] Maximum allowable building tilt angle θ c =1 / 800, maximum allowable building deformation δ c =15mm,ε vol,c =0.001,γ c =0.002

[0349] Then, based on the impact range group obtained in step S40, the numerical simulation results in step S50, and the monitoring data in step S60, the Bayesian inference method is used to comprehensively analyze and infer the above critical indicators. In this process, various uncertain factors such as geological conditions, construction technology, and monitoring data are fully considered to ensure the reliability of critical indicators.

[0350] Finally, the construction company compared the calculated critical index values ​​with the relevant engineering specifications and local regulations. It was found that all critical index values ​​met the requirements of the specifications and regulations. Therefore, these indicators were determined as the final critical impact indicators of this project, providing a reliable technical basis for subsequent construction.

[0351] By adopting the method proposed in the present invention, the pile foundation construction of the urban rail transit project can be carried out smoothly, and the adverse impact of the construction on the surrounding environment is effectively controlled. Specifically:

[0352] 1. In terms of stress influence, by rationally arranging the pile foundation, it is ensured that the maximum stress does not exceed the critical value of 0.8MPa, thus avoiding damage to surrounding buildings and underground pipelines.

[0353] 2. In terms of deformation impact, pile foundation settlement and ground deformation are strictly controlled to ensure that the maximum deformation does not exceed the critical value of 0.005, effectively preventing ground collapse and building tilt.

[0354] 3. In terms of the impact on groundwater levels, the precipitation discharge during the construction process is reasonably regulated to ensure that the groundwater level does not drop below the critical value of 1.0m, thus avoiding damage to underground pipelines and aggravated ground subsidence.

[0355] 4. Regarding vibration impact, take vibration reduction measures and strictly control the vibration acceleration to no more than 0.2m / s 2 The critical value is effectively prevented from damaging surrounding buildings and underground pipelines.

[0356] 5. In terms of the impact of ground subsidence, through reasonable pile foundation design and construction process control, it is ensured that the maximum ground settlement does not exceed the critical value of 20mm, thus avoiding damage to ground facilities.

[0357] 6. Regarding the influence of building deformation, the inclination angle of surrounding buildings is strictly limited to no more than 1 / 800, the maximum deformation is no more than 15mm, the volume strain is no more than 0.001, and the shear strain is no more than the critical value of 0.002, thus ensuring the safe use of the building.

[0358] By taking the above measures, the impact of the pile foundation construction of the urban rail transit project on the surrounding environment has been effectively controlled. The specific performance is as follows:

[0359] 1. No obvious abnormal ground stress, excessive deformation, excessive groundwater level drop, excessive vibration or ground subsidence was found in the construction area and within 50m of the surrounding area.

[0360] 2. Monitoring data from 10 surrounding high-rise buildings showed that various indicators such as tilt angle, deformation, and settlement did not exceed the critical value, and the building's function was not significantly affected.

[0361] 3. The surrounding underground pipelines are in good operating condition, and no pipeline damage or service interruption due to construction was found.

[0362] 4. Environmental factors such as construction noise and dust have been effectively controlled, and the quality of life of surrounding residents has not been significantly affected.

[0363] 5. No safety accidents caused by environmental impacts occurred during the entire construction process. The project construction progressed smoothly, making a positive contribution to urban infrastructure construction.

[0364] In summary, the method for determining the critical index of the impact of pile foundation construction on the surrounding environment proposed in this invention has been successfully applied in this urban rail transit project. This method fully considers various uncertain factors such as geological conditions, construction technology, monitoring data, etc., adopts systematic mathematical modeling and multi-source information fusion technology, determines feasible critical impact indicators, effectively controls the adverse impact of construction on the surrounding environment, and provides strong support for engineering construction and environmental protection.

[0365] Below, some data tables are used to intuitively demonstrate the application effect of the method of the present invention in this project:

[0366] Table 1 shows the three-dimensional geological model within 50m around the construction area, which clearly shows the distribution of different strata.

[0367] Table 1 Geological model parameters

[0368]

[0369] Table 2 below shows the building deformation monitoring data. Various indicators such as tilt angle and deformation amount have not exceeded the critical value.

[0370] Table 2 Building deformation monitoring data table

[0371] Monitoring Points Tilt Angle Deformation(mm) Volumetric strain Shear strain A 1 / 850 13 0.0008 0.0018 B 1 / 750 11 0.0006 0.0015

[0372] Through the above data and charts, we can intuitively see the application effect of the method of the present invention in this project. This method can not only accurately predict the impact of construction on the surrounding environment, but also determine feasible critical indicators, providing strong technical support for engineering construction and realizing the organic combination of construction and environmental protection.

[0373] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for determining critical indicators of the impact of pile foundation construction on the surrounding area, characterized in that: The following steps are involved: S10, obtaining geological data of the construction area and pile foundation data of the construction, wherein the geological data at least includes stratum structure, soil parameters and groundwater level; the pile foundation data at least includes pile diameter, pile length and pile weight; S20. Establish a three-dimensional geological model to simulate the geological conditions of the construction area and the surrounding environment; establish a hydrogeological model to predict the impact of pile foundation construction on the groundwater level and analyze the resulting ground subsidence and deformation of surrounding buildings; S30, establishing a set of equations for the influence of the pile foundation on the surroundings, including a stress balance equation, a deformation coordination equation, a seepage control equation, a vibration propagation equation, a ground settlement equation, and a building deformation equation; S40, analytically solving the equation group to obtain multiple analytical solutions, which are stress distribution function, deformation distribution function, groundwater level change function, vibration propagation function, ground settlement function and building deformation function; and parameterizing the analytical solutions according to the three-dimensional geological model and the hydrogeological model to obtain multiple range groups for representing stress influence range, deformation influence range, groundwater level influence range, vibration influence range, settlement influence range and building deformation influence range; S50, using finite element analysis to establish a numerical model of the pile foundation construction process, and simulate stress changes and stratum deformation during the construction process; S60, obtaining monitoring data from vibration monitors, settlement observation points, and groundwater level observation wells arranged at multiple key points on the pile foundation construction site, including vibration acceleration, frequency, surface settlement, building inclination angle, and groundwater level change; S70, establishing a vibration analysis model for performing vibration analysis and calculating vibration intensity and propagation characteristics during the construction process; S80, based on the range group obtained by S40, the numerical model simulation results of S50 and the monitoring data of S60, adopts the Bayesian inference method, comprehensively considers various uncertain factors, and calculates the critical indicators of the impact of pile foundation construction on the surrounding area. These critical indicators include: maximum allowable stress, maximum allowable deformation, maximum allowable groundwater level change, maximum allowable vibration acceleration, maximum allowable ground settlement and maximum allowable building deformation; S90, comparing the critical indicators obtained in S80 with engineering specifications and local regulations, determining a final critical indicator threshold range set as the critical indicator of the impact of pile foundation construction on the surrounding area and outputting it.

2. A method for determining critical indicators of the impact of pile foundation construction on the surrounding area according to claim 1, characterized in that: The three-dimensional geological model is specifically expressed as: Where G(x, y, z) represents the value of geological characteristics at the spatial point (x, y, z); n is the number of strata; α i is the weight coefficient of the i-th layer; f i (x, y, z) is the geological characteristic function of the i-th layer; The hydrogeological model is specifically expressed as follows: Where h is the water head; K x , K y , K z are the permeability coefficients in the x, y, and z directions respectively; S s is the specific water storage rate; t is the time; W is the source and sink term.

3. A method for determining critical indicators of the impact of pile foundation construction on the surrounding area according to claim 2, characterized in that: The stress balance equation is specifically expressed as: In the formula, σ xx , σ yy , σ zz is the normal stress component; τ xy , τ yz , τ zx is the shear stress component; F x , F y , F z is the body force component.

4. A method for determining critical indicators of the impact of pile foundation construction on the surrounding area according to claim 3, characterized in that: The deformation coordination equation is specifically expressed as: In the formula, ε xx , ε yy , ε zz is the positive strain component; ε xy , ε yz , ε zx is the shear strain component.

5. A method for determining critical indicators of the impact of pile foundation construction on the surrounding area according to claim 4, characterized in that: The seepage control equation is specifically expressed as: Where p is the pore pressure; k x , k y , k z are the permeabilities in the x, y, and z directions respectively; φ is the porosity; ρ is the fluid density.

6. A method for determining critical indicators of the impact of pile foundation construction on the surrounding area according to claim 5, characterized in that: The vibration propagation equation is specifically expressed as: Where u is the displacement vector; c is the wave velocity; is the Laplace operator.

7. A method for determining critical indicators of the impact of pile foundation construction on the surrounding area according to claim 6, characterized in that: The ground subsidence equation is specifically expressed as: Where S is the total settlement; n is the number of soil layers; H i is the thickness of the i-th soil layer; Δe i is the change of void ratio of the i-th soil layer; e 0i is the initial void ratio of the i-th soil layer.

8. A method for determining critical indicators of the impact of pile foundation construction on surrounding areas according to claim 7, characterized in that: The building deformation equation is specifically expressed as: In the formula, θ x ,θ y is the inclination angle of the building in the x and y directions; ΔS x , ΔS y is the settlement difference of the building in the x and y directions; L x , L y is the length of the building in the x and y directions; δ is the total deformation; u, v, w are the displacement components in the x, y, and z directions respectively; ε vol is the volume strain; γ xy , γ yz , γ zx is the shear strain component.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores program instructions, and when the program instructions are executed, they are used to execute the method for determining critical indicators of the impact of pile foundation construction on the surrounding environment as described in any one of claims 1-8.

10. A system for determining critical indicators of the impact of pile foundation construction on the surrounding area, characterized in that: A computer-readable storage medium comprising the computer-readable storage medium of claim 9.

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