Screw pile installation disturbance effect calculation method and system considering rotary shearing action

Abstract

The invention relates to the technical field of pile foundation engineering and rock-soil mechanics, in particular to a spiral pile installation disturbance effect calculation method and system considering a rotary shearing effect. The method comprises the following steps: establishing a hole expansion model of a surrounding soil body in the rotary mounting process of the screw pile according to related parameters of the screw pile, the assumed condition and the stress boundary condition; combining the stress boundary conditions, and utilizing the hole expansion model, the total equilibrium equation and the stress-strain relationship to obtain elastic region stress distribution and elastic region displacement; obtaining a stress-strain increment expression of the plastic zone by utilizing a yield function, a hardening rule and a correlation flow rule of the modified Cambridge constitutive model; according to the assumed condition, the plastic zone stress-strain increment expression, the elastic zone stress distribution and the elastic zone displacement, plastic zone stress distribution is obtained; finally, the disturbance effect is calculated according to the result. The problem that in the prior art, calculation of the installation disturbance effect of the screw pile is not accurate enough is solved.

Description

Technical Field

[0001] The invention relates to the technical field of pile foundation engineering and rock and soil mechanics, and in particular to a method and system for calculating the disturbance effect of screw pile installation considering the rotational shearing action. Background Art

[0002] With the continuous development of my country's economy, new large-scale projects have put forward higher requirements on the bearing capacity of pile foundations. As a new type of longitudinal section special-shaped pile, spiral piles have been widely used in house construction, wind power generation, retaining support and offshore oil platforms because they can provide higher bearing capacity.

[0003] At present, many studies have been conducted on the bearing characteristics of spiral piles at home and abroad, but there is a lack of research on the disturbance effect of spiral pile installation under the action of rotational shear. During the construction of spiral piles, the torque applied to the top of the pile will cause the pile body to rotate into the soil, which will cause shear stress to be generated at the orifice, exerting a disturbance effect on the soil around the pile, thereby affecting the stress field and pore water pressure of the soil around the pile, which will affect the construction safety. However, in the prior art, most of the calculations of the disturbance effect of spiral pile installation do not take into account the rotational shear effect, or take into account the rotational shear effect but the calculation is not comprehensive enough, so that the calculation of the disturbance effect of spiral pile installation is not accurate enough. Therefore, it is necessary to propose a calculation method for the disturbance effect of spiral pile installation under the action of rotational shear. This research work not only helps to predict the stress field and pore water pressure of the surrounding soil during the rotational installation of spiral piles, improve the theoretical system of spiral pile foundation, but also provide scientific design basis and construction guidance for actual projects. Summary of the invention

[0004] In view of the defects in the prior art, the present invention provides a method and system for calculating the disturbance effect of screw pile installation taking into account the rotational shear effect, thereby solving the problem that the calculation of the disturbance effect of screw pile installation in the prior art is not accurate enough.

[0005] In order to achieve the above-mentioned purpose, one aspect of the present invention provides a method for calculating the disturbance effect of screw pile installation considering the rotational shear effect, including: setting assumptions and stress boundary conditions, and establishing a pore expansion model of the surrounding soil during the rotational installation of the screw pile according to the relevant parameters of the screw pile, the assumptions and the stress boundary conditions; constructing a total equilibrium equation and a stress-strain relationship according to the pore expansion model, and obtaining the stress distribution and displacement of the elastic zone by using the pore expansion model, the total equilibrium equation and the stress-strain relationship in combination with the stress boundary conditions; based on the pore expansion model, obtaining the plastic zone stress-strain increment expression by using the yield function, hardening law and associated flow law of the modified Cambridge constitutive model; obtaining the plastic zone stress distribution according to the assumptions, the plastic zone stress-strain increment expression, the elastic zone stress distribution and the elastic zone displacement; obtaining the stress field and pore water pressure of the surrounding soil during the rotational installation of the screw pile according to the elastic zone stress distribution, the plastic zone stress distribution and the total equilibrium equation.

[0006] The present invention establishes a hole expansion model by setting assumptions and stress boundary conditions, which can accurately simulate the mechanical environment of the surrounding soil when the spiral pile is rotated and installed, and provide a reliable basis for subsequent calculations. In the process of solving the stress distribution and displacement in the elastic zone, the stress-strain increment expression in the plastic zone, and the stress distribution in the plastic zone, the total equilibrium equation, stress-strain relationship, and modified Cambridge constitutive model are comprehensively used to fully consider the elastic-plastic characteristics of the soil and the influence of rotational shear, so that the calculation results are more in line with the actual situation. The final obtained soil stress field and pore water pressure around the spiral pile will help engineers fully understand the disturbance effect during the installation of the spiral pile, thereby providing a scientific basis for the design optimization of the spiral pile, ensuring the safety and stability of the pile foundation project, improving the quality of the project, reducing construction risks, and promoting the development of pile foundation engineering and geotechnical mechanics technology.

[0007] Optionally, the combination of the stress boundary condition, the hole expansion model, the total equilibrium equation and the stress-strain relationship to obtain the stress distribution and the displacement in the elastic zone includes: according to the hole expansion model, the total equilibrium equation and the stress-strain relationship are combined to obtain a stress expression in the radial direction of the screw pile; substituting the stress boundary condition into the stress expression to obtain the stress distribution in the elastic zone; and obtaining the displacement in the elastic zone according to the stress distribution in the elastic zone.

[0008] The present invention obtains the radial stress expression of the spiral pile by combining the total equilibrium equation and the stress-strain relationship, which can comprehensively consider the mechanical response of the soil in the elastic stage and accurately describe the change law of stress with radial position. Substituting the stress boundary conditions to determine the stress distribution in the elastic zone makes the calculation results more in line with the actual engineering scenario. Obtaining the displacement in the elastic zone based on the stress distribution further reveals the deformation of the soil after being subjected to force, and provides a systematic and accurate method for studying the elastic effect of spiral pile installation on the surrounding soil. It helps to evaluate the stability of the soil during the construction process and provide strong support for engineering design and construction decisions.

[0009] Optionally, the stress distribution in the elastic region satisfies the following formula: , in, is the radial stress in the elastic region, is the initial stress of soil, is the elastic-plastic boundary radial stress, is the elastic-plastic boundary radius, is the radial radius, is the hoop stress in the elastic region.

[0010] The elastic zone stress distribution formula of the present invention clearly presents the relationship between radial and annular stresses in the elastic zone and parameters such as initial stress of the soil, elastic-plastic boundary stress and radius in a concise mathematical form. Through this formula, the stress distribution in the elastic zone can be calculated conveniently and quickly, which helps to understand the mechanical response of the surrounding soil in the elastic stage during the installation of the screw pile, and provides a quantitative basis for evaluating the stability of the soil and analyzing the interaction between the screw pile and the surrounding soil.

[0011] Optionally, the method of obtaining the plastic zone stress strain increment expression based on the hole expansion model and utilizing the yield function, hardening law and associated flow law of the modified Cambridge constitutive model includes: obtaining the stress strain increment matrix of the elastic stage of the plastic zone based on the hole expansion model and utilizing Hooke's law; obtaining the stress strain increment matrix of the plastic stage of the plastic zone based on the hole expansion model and utilizing the yield function, hardening law and associated flow law of the modified Cambridge constitutive model; superimposing the stress strain increment matrix of the elastic stage of the plastic zone and the stress strain increment matrix of the plastic stage of the plastic zone using the superposition principle to obtain the initial plastic zone stress strain increment matrix; and performing matrix inverse transformation on the initial plastic zone stress strain increment matrix to obtain the plastic zone stress strain increment expression.

[0012] The present invention obtains the stress-strain increment matrix of the elastic and plastic stages of the plastic zone through Hooke's law and the modified Cambridge constitutive model, which fully considers the characteristics of the soil in different deformation stages. Then, the matrices of the two stages are integrated through the superposition principle to obtain the initial plastic zone stress-strain increment matrix, which comprehensively covers the comprehensive mechanical response of the soil transition from elasticity to plasticity. Finally, the matrix inverse transformation is performed to obtain the final expression, which improves the accuracy of analyzing the mechanical behavior of the plastic zone soil, helps to deeply understand the disturbance of the surrounding plastic zone soil during the installation of the spiral pile, and thus provides a strong basis for optimizing the spiral pile design and ensuring the safety and stability of the project.

[0013] Optionally, the plastic zone stress-strain increment expression satisfies the following formula: , , , , , , , , , , , , , , , , , in, , and They are simplified symbols of mathematical expressions. is the elastic modulus of the soil, is the compression parameter, is the rebound parameter, is the Poisson's ratio of the soil, is the critical state stress ratio, is the stress ratio, is the mean effective stress, is the effective radial stress, is the effective hoop stress, The effective vertical stress, is the shear stress, is the radial strain, is the hoop strain, is the vertical strain, is the shear strain.

[0014] The combination of parameters in the plastic zone stress-strain increment expression of the present invention accurately describes the stress-strain relationship in the plastic zone, providing a quantitative tool for mechanical analysis of the soil around the screw pile. The inclusion of key parameters such as elastic modulus and Poisson's ratio can comprehensively consider the influence of soil material properties on mechanical response and improve calculation accuracy. Based on this expression, the stress-strain changes in the plastic zone soil can be deeply analyzed, which helps to evaluate the disturbance of the surrounding soil during the installation of the screw pile, provides strong support for the design and construction of pile foundation engineering, and improves the accuracy of the calculation of the plastic zone stress-strain increment.

[0015] Optionally, the method of obtaining the stress-strain increment matrix of the plastic stage in the plastic zone based on the hole expansion model and utilizing the yield function, hardening law and associated flow law of the modified Cambridge constitutive model includes: obtaining the strain increment expression of the plastic stage in the plastic zone based on the hole expansion model and utilizing the yield function and the associated flow law; obtaining the average effective stress differential equation and the generalized shear stress differential equation according to the formulas of the average effective stress and the generalized shear stress; substituting the hardening law into the strain increment expression of the plastic stage in the plastic zone, and obtaining the plastic factor expression by combining the average effective stress differential equation and the generalized shear stress differential equation; substituting the plastic factor expression into the strain increment expression of the plastic stage in the plastic zone to obtain the stress-strain increment matrix of the plastic stage in the plastic zone.

[0016] The present invention uses the yield function and the associated flow law to obtain the strain increment expression in the plastic stage, which accurately reflects the intrinsic connection between the stress and strain increment of the soil during plastic deformation, and lays the foundation for in-depth analysis of the plastic behavior of the soil. The plastic factor expression is obtained through the hardening law and the strain increment expression in the plastic stage, which effectively considers the hardening characteristics of the soil during the plastic deformation process, that is, the changes in the strength and stiffness of the soil as the deformation develops. The plastic factor expression is substituted for the strain increment expression to obtain the stress-strain increment matrix, which comprehensively integrates the various mechanical properties of the soil, so that the matrix can more accurately describe the mechanical response of the plastic zone soil under complex stress states. It can provide more reliable data for engineering designers, help them optimize the design and construction plan of screw piles, and improve the stability and safety of the project.

[0017] Optionally, obtaining the stress distribution in the plastic zone according to the assumed conditions, the incremental expression of stress-strain in the plastic zone, the stress distribution in the elastic zone and the displacement in the elastic zone includes: obtaining the incremental expression of strain using the undrained soil condition and the plane strain condition; substituting the incremental expression of strain into the incremental expression of stress-strain in the plastic zone to obtain the first-order differential equation of the stress component in the radial direction of the screw pile; obtaining the elastic-plastic boundary stress using the stress distribution in the elastic zone, the definition of generalized shear stress and the yield function; obtaining the radius of the elastic-plastic boundary using the elastic zone displacement and the undrained soil condition; substituting the elastic-plastic boundary stress and the radius of the elastic-plastic boundary into the first-order differential equation for iterative solution to obtain the stress distribution in the plastic zone.

[0018] The present invention obtains the strain increment expression with the help of the undrained soil condition and the plane strain condition, which closely fits the drainage and deformation state of the soil in the actual project, and provides basic data that conforms to the actual situation for subsequent calculations. Substituting it into the plastic zone stress-strain increment expression obtains the first-order differential equation, and converts the complex stress-strain relationship into a mathematical form that is easy to solve. The elastic-plastic boundary stress is determined by the elastic zone stress distribution, the definition of generalized shear stress and the yield function, and the elastic-plastic boundary radius is obtained by combining the elastic zone displacement and the undrained soil condition, which accurately defines the boundary conditions for the plastic zone calculation. Finally, the elastic-plastic boundary stress and radius are substituted into the first-order differential equation for iterative solution, and the stress distribution in the plastic zone can be accurately obtained. It not only helps to deeply understand the stress change law of the plastic zone soil during the installation of the spiral pile, but also provides a key basis for evaluating the bearing capacity and stability of the spiral pile, thereby optimizing the design parameters and construction process of the spiral pile, improving the quality of the project, and reducing the project risk.

[0019] Optionally, obtaining the stress field and pore water pressure of the surrounding soil during the rotational installation of the screw pile according to the stress distribution in the elastic zone, the stress distribution in the plastic zone and the total equilibrium equation includes: obtaining the pore water pressure in the elastic zone by utilizing the stress distribution in the elastic zone; integrating the total equilibrium equation to obtain an integral expression of the excess pore water pressure in the radial direction of the screw pile; obtaining the excess pore water pressure according to the integral expression; superimposing the pore water pressure in the elastic zone and the excess pore water pressure to obtain the pore water pressure in the plastic zone; combining the pore water pressure in the plastic zone, the stress distribution in the elastic zone, the pore water pressure in the elastic zone and the stress distribution in the plastic zone to obtain the stress field and pore water pressure of the surrounding soil during the rotational installation of the screw pile.

[0020] The present invention obtains the pore water pressure in the elastic zone from the stress distribution in the elastic zone, provides basic data for the overall calculation, and reasonably reflects the pore water pressure of the soil in the elastic stage. The integral expression of the excess pore water pressure is obtained by integrating the total equilibrium equation, and then the excess pore water pressure is obtained, which effectively considers the changes in pore water pressure caused by factors such as soil deformation during the installation of the screw pile. The pore water pressure in the elastic zone is superimposed with the excess pore water pressure to obtain the pore water pressure in the plastic zone, which comprehensively covers the influencing factors of the pore water pressure in different stages. Combining the pore water pressure in the plastic zone, the stress distribution in the elastic zone and the plastic zone, and the pore water pressure in the elastic zone can accurately present the complete stress field and pore water pressure state of the surrounding soil during the rotational installation of the screw pile. This provides a key basis for engineers to evaluate the impact of the installation of the screw pile on the stability of the surrounding soil, and further improves the accuracy of the calculation of the disturbance effect of the installation of the screw pile.

[0021] Optionally, the excess pore water pressure satisfies the following formula: , in, is the excess pore water pressure, is the effective radial stress at the elastic-plastic boundary, is the radial radius associated with the excess pore water pressure, The radius The effective radial stress at is the radius of the elastic-plastic interface, is the effective radial stress, is the effective hoop stress, is the integration variable.

[0022] The pore water pressure in the plastic zone satisfies the following formula: , in, is the pore water pressure in the plastic zone, is the pore water pressure in the elastic zone, is the excess pore water pressure.

[0023] The excess pore water pressure formula of the present invention comprehensively considers the change of stress along the radial direction, and can accurately reflect the excess pore water pressure generated in the soil due to stress change when the screw pile is installed. On this basis, the plastic zone pore water pressure formula combines the elastic zone pore water pressure to completely derive the pore water pressure in the plastic zone, thereby improving the accuracy of the calculation.

[0024] Another aspect of the present invention provides a system for calculating the disturbance effect of screw pile installation based on rotational shear, comprising: a processor, an input device, an output device and a memory, wherein the processor, the input device, the output device and the memory are interconnected, wherein the memory is used to store a computer program, the computer program includes program instructions, and the processor is configured to call the program instructions to execute any one of the methods for calculating the disturbance effect of screw pile installation considering the rotational shear provided in the previous aspect of the present invention.

[0025] The system for calculating the disturbance effect of spiral pile installation based on rotational shearing action of the present invention has a compact structure, stable performance, high integration and simple composition, and can stably execute the method for calculating the disturbance effect of spiral pile installation considering the rotational shearing action provided in the previous aspect of the present invention, thereby further improving the overall applicability and practical application capability of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A flow chart of a method for calculating the disturbance effect of screw pile installation considering rotational shearing according to an embodiment of the present invention; Figure 2 A cross-sectional view of a screw pile and hole expansion model in a method for calculating the disturbance effect of screw pile installation considering rotational shearing in an embodiment of the present invention; Figure 3 It is a schematic diagram of the structure of a system for calculating the disturbance effect of screw pile installation based on rotational shearing according to an embodiment of the present invention. DETAILED DESCRIPTION

[0027] The specific embodiments of the present invention will be described in detail below. It should be noted that the embodiments described herein are only for illustration and are not intended to limit the present invention. In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present invention. However, it is obvious to those of ordinary skill in the art that these specific details do not need to be adopted to implement the present invention. In other examples, in order to avoid confusing the present invention, known circuits, software or methods are not specifically described.

[0028] Throughout the specification, references to "one embodiment," "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment of the present invention. Therefore, the phrases "in one embodiment," "in an embodiment," "an example," or "an example" appearing in various places throughout the specification do not necessarily all refer to the same embodiment or example. In addition, particular features, structures, or characteristics may be combined in one or more embodiments or examples in any suitable combination and / or subcombination. In addition, it should be understood by those of ordinary skill in the art that the figures provided herein are for illustrative purposes and that the figures are not necessarily drawn to scale.

[0029] Figure 1 The flowchart of the method for calculating the disturbance effect of screw pile installation considering the rotational shearing effect according to the embodiment of the present invention solves the problem that the calculation of the disturbance effect of screw pile installation in the prior art is not accurate enough. Figure 1 The method shown comprises the following steps: Step S1, setting assumptions and stress boundary conditions, and establishing a hole expansion model of the surrounding soil during the rotation installation of the screw pile according to relevant parameters of the screw pile, the assumptions and the stress boundary conditions.

[0030] In this embodiment, the screw pile and hole expansion model are as follows Figure 2 As shown, an initial radius is The circular hole is located in an infinite isotropic soil body, and the initial stress of the soil body is (at infinity), the orifice is subjected to uniformly distributed radial pressure and shear stress (The present invention defines , where b is a value between 0 and 1 for the magnitude of the reaction shear stress. is the undrained shear strength of the soil). The hole is expanded from the initial radius to the Expand to radius , the radius of the elastic-plastic interface is , the displacement at the elastic-plastic interface is The initial pore water pressure is .

[0031] For the convenience and feasibility of calculation, assumptions and boundary conditions are proposed.

[0032] Assume that the following conditions are met: (1) The elastic deformation of the soil is described by Hooke’s law, and the plastic deformation of the soil is described by the modified Cambridge constitutive model.

[0033] (2) The hole expansion process conforms to the plane strain model.

[0034] (3) The soil is undrained, that is, the volume strain is 0.

[0035] (4) The small deformation assumption is used in the elastic zone, and the large strain assumption is used in the plastic zone.

[0036] The boundary conditions are met: (1) When the radial radius is equal to the radius of the screw pile, the effective radial stress is equal to the radial stress acting on the screw pile body (i.e. at the hole mouth), and the shear stress , where b is a coefficient between 0 and 1 that reflects the magnitude of shear stress. is the undrained shear strength of the soil.

[0037] (2) When the radial radius tends to infinity, the effective radial stress is equal to the initial stress at infinity, and the shear stress is 0 at this time.

[0038] The rotational installation of the screw pile is regarded as a quasi-static hole expansion process. The soil produces radial displacement and stress redistribution under the action of the pile. When establishing the hole expansion model of the surrounding soil during the rotational installation of the screw pile, the relevant parameters of the screw pile, such as the pile diameter and pitch, must be clarified first. These parameters directly affect the force and deformation of the soil. Based on the given assumptions, the actual complex soil properties are simplified.

[0039] Step S2, constructing a total equilibrium equation and a stress-strain relationship according to the hole expansion model, combining the stress boundary conditions, and using the hole expansion model, the total equilibrium equation and the stress-strain relationship to obtain the stress distribution and displacement in the elastic region.

[0040] Wherein, combining the stress boundary condition, using the hole expansion model, the total equilibrium equation and the stress-strain relationship, obtaining the stress distribution and displacement of the elastic region specifically includes the following sub-steps: Step S201, based on the hole expansion model, the total equilibrium equation and the stress-strain relationship are combined to obtain a stress expression for the radial direction of the screw pile.

[0041] In this embodiment, based on the established hole expansion model, the total equilibrium equation describes the mechanical equilibrium relationship of the soil under stress, while the stress-strain relationship reflects the mechanical properties of the soil material itself. The combination of the two is to comprehensively and accurately solve the stress in the radial direction of the screw pile.

[0042] Starting from the total equilibrium equation, it takes into account the balance of forces in all directions of the soil, including the forces exerted on the surrounding soil during the installation of the screw pile and the reaction force of the soil itself. The stress-strain relationship can link the stress on the soil with the strain generated.

[0043] In the process of joint equation, some intermediate variables are eliminated through mathematical derivation and transformation, and the equation is gradually simplified to an expression only about the radial stress of the screw pile. This process requires the precise application of mechanical and mathematical knowledge, and the consideration of various mechanical parameters of the soil, such as elastic modulus, Poisson's ratio, etc. The stress expression finally obtained not only reflects the relationship between the radial stress of the screw pile and the mechanical properties of the soil, but also reflects the influence of hole expansion on the stress distribution of the soil during the installation of the screw pile, which provides an important theoretical basis for in-depth research on the interaction between the screw pile and the soil.

[0044] like Figure 2 For the pore expansion model shown in the figure, the overall equilibrium equation satisfies the following formula: , in, is the effective radial stress, is the pore water pressure, is the radial radius, which is used to determine the distance between a point in the soil and the center of the hole. In the hole expansion problem, the stress and strain states of the soil at different radial positions are different. It is the angle of rotation around the central axis of the screw pile, which is used to describe the position of a point in the soil in the circumferential direction, and is convenient for determining the mechanical state of each point in the soil in the cylindrical coordinate system. is the shear stress, is the effective hoop stress.

[0045] The radial strain, hoop strain and shear strain can be expressed as: , , , in, is the radial displacement, is the circumferential displacement, is the radial strain, is the hoop strain, is the shear strain, is the radial coordinate, It is the angle of rotation around the central axis of the screw pile.

[0046] Since uniform radial pressure and shear stress are applied at the orifice, the differential of its displacement with respect to the angle is 0, that is, and , so the above formula can be simplified to: , , , Will Elimination yields: , Since the soil is in the elastic region, its stress-strain relationship is as follows: , , , , , in, is the elastic modulus of the soil, is the Poisson's ratio of the soil, is the shear modulus.

[0047] The stress expression in the radial direction of the screw pile can be obtained by combining the total equilibrium equation, stress-strain relationship and deformation coordination equation. The stress expression satisfies the following formula: , , , in, and is an integral constant, and its value can be obtained through the stress boundary condition.

[0048] Step S202, substituting the stress boundary condition into the stress expression to obtain the stress distribution in the elastic region.

[0049] In this embodiment, after obtaining the stress expression in the radial direction of the screw pile, the stress boundary condition plays a key constraint role. The stress boundary condition specifies the stress state on the model boundary, such as the stress value on the pile hole surface and the stress condition of the soil at infinity.

[0050] Substituting these boundary conditions into the stress expression actually determines the specific parameters and ranges for the stress expression. In the elastic zone, the soil follows the laws of elastic mechanics, and the stress and strain are linearly related. By substituting the boundary conditions, the unknown constants in the stress expression can be eliminated, thereby obtaining the stress distribution in the elastic zone that conforms to the actual physical situation.

[0051] The stress distribution in the elastic zone reflects the stress magnitude and change law at different positions when the surrounding soil is in the elastic deformation stage during the screw pile rotation installation process. It has important guiding significance for analyzing the interaction between the screw pile and the soil, evaluating the stability of the soil, and further optimizing the design and construction process of the screw pile.

[0052] The stress boundary provided by the present invention can be expressed as: when hour ; when hour ; when hour ; when hour .

[0053] Using the given stress boundary conditions, the stress formula in the elastic region can be obtained, which is derived as follows: , , , , Considering that the subsequent derivation needs to involve the stress of the elastic-plastic boundary surface, the stress formula of the elastic zone adopts the stress expression of the elastic-plastic boundary surface, which is in the following form: , , , That is, the stress distribution in the elastic region satisfies the following formula: , in, is the radial stress in the elastic region, is the initial stress of soil, is the elastic-plastic boundary radial stress, is the elastic-plastic boundary radius, is the radial radius, is the hoop stress in the elastic region, is the radius of the hole after expansion, is the stress difference between the radial stress and the initial stress, is the stress difference between the elastic-plastic boundary radial stress and the initial stress, is a value between 0 and 1 that reflects the magnitude of shear stress. is the undrained shear strength of the soil.

[0054] Step S203, obtaining elastic region displacement according to the elastic region stress distribution.

[0055] In this embodiment, when the stress distribution in the elastic zone is clear, the displacement in the elastic zone is further derived through the stress-strain relationship related thereto and combined with relevant principles such as material mechanics. This process is based on the established spiral pile rotation installation hole expansion model, starting from the stress distribution in the elastic zone, considering the mechanical properties of the soil in the elastic stage, and finally obtaining the displacement in the elastic zone through reasonable mathematical deduction and calculation.

[0056] The radial displacement can be expressed as: , The shear strain can be obtained by combining the stress-strain relationship. Substituting the shear strain into the simplified shear strain equation yields: , Integrating the above equation yields: , Let the circumferential displacement at the orifice be (mainly radial displacement), and substitute it into the above equation to obtain a new expression: , , in, is the radial displacement, is the stress difference between the elastic-plastic boundary radial stress and the initial stress, is the elastic-plastic boundary radius, is the elastic-plastic boundary radial stress, is the shear modulus, , is the radial radius, is the circumferential displacement, is the circumferential displacement at the orifice, L is the integral constant, is the radius of the hole after expansion, is a value between 0 and 1 that reflects the magnitude of shear stress. is the undrained shear strength of the soil.

[0057] Step S3, based on the pore expansion model, using the yield function, hardening law and associated flow law of the modified Cambridge constitutive model, obtain the stress-strain increment expression in the plastic zone.

[0058] Wherein, based on the pore expansion model, using the yield function, hardening law and associated flow law of the modified Cambridge constitutive model, obtaining the stress-strain increment expression in the plastic zone specifically includes the following sub-steps: Step S301, based on the hole expansion model, using Hooke's law to obtain the stress-strain increment matrix of the elastic stage in the plastic zone.

[0059] In this embodiment, the modified Cambridge constitutive model is used to describe the stress and strain in the plastic zone of the soil around the screw pile, and the strain increment in the plastic zone is divided into two stages: one is the strain increment generated in the elastic stage, and the other is the strain increment generated in the plastic stage.

[0060] Hooke's law can describe the linear relationship between stress and strain of materials within the elastic range. By applying this law, the stress on the soil is linked to the strain increment generated. After a series of mathematical derivations and calculations, the stress-strain increment matrix of the elastic stage in the plastic zone is finally obtained. This matrix quantitatively shows the relationship between the stress and strain increment of the soil in the elastic stage in the plastic zone.

[0061] The stress-strain increment matrix in the elastic stage of the plastic zone satisfies the following formula: , in, is the radial strain increment in the elastic stage of the plastic zone, is the circumferential strain increment in the elastic stage of the plastic zone, is the vertical strain increment in the elastic stage of the plastic zone, is the shear stress increment in the elastic stage of the plastic zone, is the shear strain increment in the elastic stage of the plastic zone, is the Poisson's ratio of the soil, is the radial effective stress increment in the elastic stage of the plastic zone, is the effective annular stress increment in the elastic stage of the plastic zone, is the vertical effective stress increment in the elastic stage of the plastic zone.

[0062] According to the definition of mean effective stress, we can get: , Substituting this formula into the above matrix equation, we can get: , Since the volumetric strain increment is zero in undrained conditions, the differential of the mean effective stress can be obtained: , in, is the mean effective stress, is the effective radial stress, is the effective hoop stress, The effective vertical stress, is the volumetric strain increment.

[0063] Step S302, based on the pore expansion model, using the yield function, hardening law and associated flow law of the modified Cambridge constitutive model, obtain the stress-strain increment matrix of the plastic stage in the plastic zone.

[0064] Wherein, based on the pore expansion model, using the yield function, hardening law and associated flow law of the modified Cambridge constitutive model, obtaining the stress-strain increment matrix in the plastic stage of the plastic zone specifically includes the following sub-steps: Step S30201, based on the pore expansion model, using the yield function and the associated flow law, obtain the strain increment expression of the plastic stage in the plastic zone.

[0065] In this embodiment, the yield function defines the conditions for the soil to enter plastic deformation, and the associated flow law establishes the relationship between the plastic strain increment and the stress. Based on these theories, the strain increment corresponding to each stress component is determined through mathematical derivation, and finally the strain increment expression of the plastic stage in the plastic zone is obtained, which lays the foundation for the subsequent analysis of the mechanical behavior of the soil in the plastic zone.

[0066] The yield function of the modified Cambridge constitutive model is as follows: , The generalized shear stress q is defined as follows: , According to the associated flow law, the strain increment corresponding to each stress component can be determined, and its expression is as follows: , , , , Therefore, the expression of strain increment in the plastic stage satisfies the following formula: , , , , in, is the hardening parameter, M is the critical state stress ratio, q is the generalized shear stress, is the mean effective stress, , , and Represent the strain increments in the radial, circumferential, vertical and shear directions in the plastic stage of the plastic zone, respectively. is the plasticity factor, and its expression can be obtained using the modified Cambridge model hardening law. is the effective radial stress, is the effective hoop stress, The effective vertical stress, is the shear stress.

[0067] Step S30202: According to the formulas of mean effective stress and generalized shear stress, obtain the mean effective stress differential equation and the generalized shear stress differential equation.

[0068] In this embodiment, the average effective stress and the generalized shear stress are important parameters for analyzing the stress state of the soil. Based on the formulas of these two parameters, the average effective stress differential equation and the generalized shear stress differential equation are obtained by mathematically deriving and transforming them. The average effective stress formula is a comprehensive calculation of each stress component, and the generalized shear stress formula is used to measure the shear strength of the soil. By differentiating them, the law of the change of the average effective stress and the generalized shear stress with the stress component is revealed.

[0069] The formula for mean effective stress is as follows: , From this, the differential equation of the mean effective stress is obtained as: , The formula for generalized shear stress is as follows: , From this, the differential equation for generalized shear stress is obtained as follows: , in, is the mean effective stress, is the effective radial stress, is the effective hoop stress, The effective vertical stress, is the stress component, is the Kroneck symbol, is the generalized shear stress, is the shear stress.

[0070] Step S30203, substituting the hardening law into the strain increment expression of the plastic stage in the plastic zone, and combining the average effective stress differential equation and the generalized shear stress differential equation to obtain the plasticity factor expression.

[0071] In this embodiment, the hardening law describes the changing characteristics of the strength and stiffness of the soil during plastic deformation, providing a basis for the study of the changes in the soil's own properties. At the same time, combined with the average effective stress differential equation and the generalized shear stress differential equation, these two equations reflect the law of the change of the average effective stress and the generalized shear stress with the stress component. By combining these three, a series of mathematical operations and derivations are performed, and the relationship between the soil stress change, deformation characteristics and the change of its own properties is fully considered, and finally the plasticity factor expression is obtained.

[0072] According to the hardening law, we can get: , , Where, e is the void ratio, is the compression parameter, is the rebound parameter, Symbols defined to simplify mathematical expressions. Other variables have the same definitions as above.

[0073] Hardening parameters It can be expressed as: , The differentials of the mean effective stress and generalized shear stress are expressed as: , , Substituting the hardening law into the associated flow law equation and combining the differentials of the mean effective stress and the generalized shear stress, we obtain The expression is: , , , , in, is the stress ratio, M is the critical stress ratio, q is the generalized shear stress, and These are symbols defined to simplify mathematical expressions. Other variables are defined the same as above.

[0074] Step S30204, substituting the plasticity factor expression into the strain increment expression of the plastic stage in the plastic zone to obtain the stress-strain increment matrix of the plastic stage in the plastic zone.

[0075] In this embodiment, the plasticity factor expression reflects the characteristic parameters related to the hardening law, average effective stress and generalized shear stress of the soil during the plastic deformation process, and the strain increment expression of the plastic stage in the plastic zone describes the strain increment relationship corresponding to each stress component in the plastic stage. The plasticity factor expression is substituted into the strain increment expression of the plastic stage in the plastic zone, and through mathematical operations and sorting after substitution, the relationship between the stress and strain factors of the soil in the plastic deformation stage is comprehensively considered, and finally the stress-strain increment matrix of the plastic stage in the plastic zone is obtained. This matrix can more comprehensively and accurately describe the quantitative relationship between stress and strain increments of the soil in the plastic zone under complex stress states.

[0076] The stress-strain increment matrix in the plastic stage of the plastic zone satisfies the following formula: , , , , , , Step S303, using the superposition principle, superimpose the stress-strain increment matrix in the elastic stage of the plastic zone and the stress-strain increment matrix in the plastic stage of the plastic zone to obtain an initial stress-strain increment matrix in the plastic zone.

[0077] In this embodiment, the superposition principle is used in mechanical analysis to integrate multiple related matrices to obtain more comprehensive mechanical information. The above two matrices are superimposed to integrate the stress-strain increment characteristics of the soil in the elastic and plastic stages, eliminating the isolation of the analysis at different stages, thereby obtaining an initial plastic zone stress-strain increment matrix that comprehensively reflects the overall mechanical response of the soil in the plastic zone from the elastic stage to the plastic stage. This new matrix covers the comprehensive information of the stress-strain increment of the soil in these two stages.

[0078] The initial plastic zone stress-strain increment matrix satisfies the following formula: , in, , , and Represent radial, annular, vertical and shear strains, S, , , and Symbols defined to simplify mathematical expressions. Other variables have the same definitions as above.

[0079] Step S304, performing matrix inverse transformation on the initial plastic zone stress-strain increment matrix to obtain a plastic zone stress-strain increment expression.

[0080] In this embodiment, in order to further study the variation law of stress and strain in the plastic zone soil, it is necessary to use the strain increment as a known quantity to solve the expression of the stress increment. Therefore, the initial plastic zone stress-strain increment matrix is ​​processed by the mathematical method of matrix inverse transformation. Matrix inverse transformation is a linear algebraic operation, through which the elements in the matrix can be recombined to achieve the conversion from strain increment to stress increment.

[0081] After matrix inverse transformation, the expression of stress-strain increment in the plastic zone was successfully obtained. This expression can more directly reflect the quantitative relationship between stress and strain increment in the plastic zone soil during the installation of screw piles, and provides a key quantitative basis for accurately analyzing the disturbance effect of screw pile installation on the surrounding plastic zone soil.

[0082] The stress-strain increment expression in the plastic zone satisfies the following formula: , , , , , , , , , , , , , , , , , in, , and They are simplified symbols of mathematical expressions. is the elastic modulus of the soil, is the compression parameter, is the rebound parameter, is the Poisson's ratio of the soil, is the critical state stress ratio, is the stress ratio, is the mean effective stress, is the effective radial stress, is the effective hoop stress, The effective vertical stress, is the shear stress, is the radial strain, is the hoop strain, is the vertical strain, is the shear strain.

[0083] Step S4, obtaining the stress distribution in the plastic zone according to the assumption, the stress-strain increment expression in the plastic zone, the stress distribution in the elastic zone and the displacement in the elastic zone.

[0084] Wherein, the step of obtaining the stress distribution in the plastic zone according to the assumption, the stress-strain increment expression in the plastic zone, the stress distribution in the elastic zone and the displacement in the elastic zone specifically comprises the following sub-steps: Step S401, using the undrained soil condition and the plane strain condition, obtain a strain increment expression.

[0085] In this embodiment, the undrained soil condition means that the volume of the soil will not change during the whole process, that is, the volume strain is 0, and the plane strain condition stipulates that the strain increment of the soil in a certain direction is 0. Combined with relevant theoretical knowledge such as logarithmic strain, through mathematical derivation and analysis, the strain increment expression is finally obtained.

[0086] In this embodiment, due to the undrained condition of the soil, the volume of the soil will not change, that is: , According to the plane strain assumption, that is: , Using logarithmic strain, the strain increment expression satisfies the following expression: , The variable definitions are the same as above.

[0087] Step S402: Substitute the strain increment expression into the plastic zone stress strain increment expression to obtain a first-order differential equation of the stress component in the radial direction of the screw pile.

[0088] In this embodiment, the strain increment expression is substituted into the plastic zone stress-strain increment expression. This operation is a key step in combining the soil strain change with the plastic zone stress-strain relationship. Through this substitution, mathematical operations and derivations are used to transform the complex stress-strain relationship into a mathematical form about the radial direction of the screw pile, thereby obtaining the first-order differential equation of the stress component about the radial direction of the screw pile.

[0089] The first-order differential equation satisfies the following formula: , , , , Step S403, obtaining elastic-plastic boundary stress by using the elastic region stress distribution, the definition of generalized shear stress and the yield function.

[0090] In this embodiment, based on the definition of generalized shear stress and combined with the stress value in the stress distribution of the elastic zone, an expression related to the generalized shear stress is constructed, and then the yield function is used to establish an equation relationship under the condition that the soil reaches the yield state at the elastic-plastic boundary. By combining related formulas, the unknown quantity is solved to obtain the elastic-plastic boundary stress.

[0091] In this embodiment, the effective radial and hoop stresses at infinity are defined as: , is the effective radial stress at infinity, is the effective hoop stress at infinity.

[0092] The soil at the elastic-plastic boundary reaches the yield state. According to the yield equation, the elastic-plastic boundary stress satisfies the following relationship: , in, is the generalized shear stress at the elastoplastic boundary, is the average effective stress of the elastic-plastic interface, is the maximum prior consolidation pressure, and other variables are defined as above.

[0093] Since the effective stress in the elastic stage remains unchanged, the generalized shear stress at the elastic-plastic boundary satisfies the following expression: , , , , in, is the overconsolidation ratio, is the initial mean effective stress.

[0094] According to the definition of generalized shear stress, another expression is as follows: , Since the stress at the elastic-plastic interface obeys the stress formula in the elastic region, the following relationship can be obtained: , Combining the above formulas, we can get: , , in, is the effective radial stress at the elastic-plastic boundary, is the effective hoop stress at the elastic-plastic boundary, is the shear stress at the elastic-plastic interface, which can be obtained from the stress expression in the elastic region. is the effective radial stress at infinity, is the effective hoop stress at infinity, and other variables are defined as above.

[0095] Step S404: using the elastic zone displacement and the undrained condition of the soil, the radius of the elastoplastic boundary is obtained.

[0096] In this embodiment, it can be seen from the elastic zone displacement formula that it is associated with the stress and radius at the elastic-plastic boundary. At the same time, the undrained soil condition makes the soil volume unchanged, so the relationship equation between the radii can be established. Substitute the elastic zone displacement formula into the equation obtained due to the undrained soil condition, and through mathematical transformation and derivation, gradually eliminate other variables, and finally obtain an expression for the elastic-plastic boundary radius. The determination of the elastic-plastic boundary radius is the key link for the subsequent accurate calculation of the stress distribution in the plastic zone and in-depth study of the disturbance effect of the screw pile installation, which provides important basic data for the entire study.

[0097] From the elastic zone displacement formula: , Due to the undrained condition of the soil, the volume of the soil remains unchanged during the whole process, so the following relationship holds true: , Substituting the elastic zone displacement formula into the equation, we get: , Will Substituting into the above formula, we get The expression is as follows: , in, is the current radial radius, is the initial radial radius, is the radius of soil when it yields immediately, is the radius of the elastic-plastic interface, Initial radius of the hole, is the radius of the hole after expansion, and other variables are defined as above.

[0098] Step S405: Substitute the elastic-plastic boundary stress and the radius of the elastic-plastic boundary into the first-order differential equation for iterative solution to obtain the stress distribution in the plastic zone.

[0099] In this embodiment, the elastic-plastic boundary stress and radius are substituted into the first-order differential equation to combine the boundary condition with the stress change equation. Since the equation is difficult to solve directly, an iterative algorithm is used. The iterative algorithm updates the parameters based on the previous calculation results through repeated calculations, and gradually approaches the true solution. In the process of multiple iterations, the calculation parameters are continuously adjusted until the calculation results meet the preset accuracy requirements, and finally an accurate stress distribution in the plastic zone is obtained.

[0100] Step S5, obtaining the stress field and pore water pressure of the surrounding soil during the rotational installation of the screw pile according to the stress distribution in the elastic zone, the stress distribution in the plastic zone and the total equilibrium equation.

[0101] Wherein, obtaining the stress field and pore water pressure of the surrounding soil during the rotational installation of the screw pile according to the stress distribution in the elastic zone, the stress distribution in the plastic zone and the total equilibrium equation specifically includes the following sub-steps: Step S501, using the elastic region stress distribution, obtaining the elastic region pore water pressure.

[0102] In this embodiment, based on the stress distribution in the elastic region and combined with the effective stress principle, the pore water pressure in the elastic region can be derived when the total stress distribution in the elastic region is known and the average effective stress is determined to be constant. First, the total stress at each point in the elastic region is determined, and then the pore water pressure value corresponding to each point is calculated based on the condition of constant average effective stress. This method of calculating pore water pressure based on stress distribution can accurately determine the distribution of pore water pressure in the elastic region.

[0103] Step S502: Integrate the total equilibrium equation to obtain an integral expression of excess pore water pressure in the radial direction of the screw pile.

[0104] In this embodiment, integrating the total balance equation is a key step in obtaining the integral expression of excess pore water pressure in the radial direction of the screw pile. The total balance equation describes the balance relationship of stress in the soil, and reflects the relationship between effective radial stress, effective annular stress, pore water pressure and shear stress. When integrating the total balance equation, different characteristics and boundary conditions of the soil need to be taken into account.

[0105] In the integration process, the integration constant should be determined according to the specific stress-strain relationship and boundary conditions. By integrating the total equilibrium equation from the elastoplastic boundary to the plastic zone, each stress component can be linked to the position variable in the radial direction of the screw pile, and finally the integral expression of the excess pore water pressure in the radial direction of the screw pile is obtained, which clearly shows the variation trend of the excess pore water pressure with radial distance. This expression provides a strong mathematical basis for further studying the variation law of the pore water pressure of the soil during the installation of the screw pile, and is of great significance for evaluating the disturbance effect of the installation of the screw pile on the surrounding soil.

[0106] Step S503, obtaining the excess pore water pressure according to the integral expression.

[0107] In this embodiment, the integral expression is derived by comprehensively considering factors such as soil stress equilibrium, stress-strain characteristics, and boundary conditions, and contains the mathematical connection between excess pore water pressure and the radial position of the screw pile. Based on this integral expression, combined with specific boundary conditions and known parameters, the specific values ​​of excess pore water pressure at different radial positions can be obtained by solving the expression using mathematical calculation methods.

[0108] The excess pore water pressure satisfies the following formula: , in, is the excess pore water pressure, is the effective radial stress at the elastic-plastic boundary, is the radial radius associated with the excess pore water pressure, The radius The effective radial stress at is the radius of the elastic-plastic interface, is the effective radial stress, is the effective hoop stress, is the integration variable.

[0109] Step S504: superimpose the elastic zone pore water pressure and the excess pore water pressure to obtain the plastic zone pore water pressure.

[0110] In this embodiment, the superposition of the elastic zone pore water pressure and the excess pore water pressure is based on the continuity and superposition of the pore water pressure changes in the soil during the transition from the elastic state to the plastic state. Through this superposition operation, the elastic stage and the additional effects caused by the installation of the screw pile can be comprehensively considered to obtain the pore water pressure in the plastic zone, and the pore water pressure in the plastic zone fully reflects the actual situation of the pore water pressure in the plastic deformation area.

[0111] The pore water pressure in the plastic zone satisfies the following formula: , in, is the pore water pressure in the plastic zone, is the pore water pressure in the elastic zone, is the excess pore water pressure.

[0112] Step S505, combining the plastic zone pore water pressure, the elastic zone stress distribution, the elastic zone pore water pressure and the plastic zone stress distribution to obtain the stress field and pore water pressure of the surrounding soil during the screw pile rotation installation process.

[0113] In this embodiment, the pore water pressure in the plastic zone reflects the change of pore water pressure in the plastic deformation zone. It is obtained by superimposing the excess pore water pressure and the pore water pressure in the elastic zone, and reflects the characteristics of the pore water pressure of the soil in the plastic deformation stage. The stress distribution in the elastic zone shows the stress state of the soil away from the spiral pile area, which is the basis for analyzing the overall mechanical response of the soil. The pore water pressure in the elastic zone characterizes the change of pore water pressure in the elastic zone, and the stress distribution in the plastic zone presents in detail the stress of the soil in the directly affected area around the spiral pile. It reflects the redistribution and adjustment of the stress of the soil during the plastic deformation process, which is crucial to understanding the pile-soil interaction mechanism. When these data are combined, starting from the stress distribution in the elastic zone and combining the stress distribution in the plastic zone, the transition and change rules of stress in different regions are clarified. At the same time, considering the influence of the pore water pressure in the plastic zone and the pore water pressure in the elastic zone, it is possible to fully depict the stress magnitude and direction of different positions of the surrounding soil during the rotation and installation of the spiral pile, as well as the specific value of the pore water pressure.

[0114] like Figure 3 As shown, the present invention also provides a system for calculating the disturbance effect of screw pile installation based on rotational shear, comprising: a processor, an input device, an output device and a memory, wherein the processor, the input device, the output device and the memory are connected to each other, wherein the memory is used to store a computer program, the computer program includes program instructions, and the processor is configured to call the program instructions to execute the relevant steps of the relevant embodiment of the method for calculating the disturbance effect of screw pile installation considering the rotational shear of the previous aspect of the present invention.

[0115] In the screw pile installation disturbance effect calculation system based on rotational shear provided by the present invention, each functional component can be integrated into one processing component, or each component can exist physically separately, or two or more components can be integrated into one component. The above-mentioned integrated components can be implemented in the form of hardware or in the form of software functions, further improving the overall applicability and practical application ability of the present invention.

[0116] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. The calculation method of the disturbance effect of screw pile installation considering the rotational shear effect is characterized by: The method comprises: Setting assumptions and stress boundary conditions, and establishing a hole expansion model of the surrounding soil during the rotation installation of the screw pile according to the relevant parameters of the screw pile, the assumptions and the stress boundary conditions; Constructing a total equilibrium equation and a stress-strain relationship according to the hole expansion model, combining the stress boundary conditions, and using the hole expansion model, the total equilibrium equation and the stress-strain relationship to obtain the stress distribution and displacement in the elastic region; Based on the pore expansion model, the yield function, hardening law and associated flow law of the modified Cambridge constitutive model are used to obtain the stress-strain increment expression in the plastic zone; Obtaining the stress distribution in the plastic zone according to the assumption, the stress-strain increment expression in the plastic zone, the stress distribution in the elastic zone, and the displacement in the elastic zone; According to the stress distribution in the elastic zone, the stress distribution in the plastic zone and the total equilibrium equation, the stress field and pore water pressure of the surrounding soil during the rotation installation of the screw pile are obtained.

2. The method for calculating the disturbance effect of screw pile installation considering the rotational shear action according to claim 1 is characterized in that: The combining of the stress boundary conditions and utilizing the hole expansion model, the total equilibrium equation and the stress-strain relationship to obtain the stress distribution and displacement in the elastic region comprises: According to the hole expansion model, the total equilibrium equation and the stress-strain relationship are combined to obtain an expression for the stress in the radial direction of the screw pile; Substituting the stress boundary condition into the stress expression to obtain the stress distribution in the elastic region; According to the stress distribution in the elastic region, the displacement in the elastic region is obtained.

3. The method for calculating the disturbance effect of screw pile installation considering the rotational shear action according to claim 2 is characterized in that: The stress distribution in the elastic region satisfies the following formula: ， in, is the radial stress in the elastic region, is the initial stress of soil, is the elastic-plastic boundary radial stress, is the elastic-plastic boundary radius, is the radial radius, is the hoop stress in the elastic region.

4. The method for calculating the disturbance effect of screw pile installation considering the rotational shear action according to claim 1 is characterized in that: Based on the pore expansion model, the yield function, hardening law and associated flow law of the modified Cambridge constitutive model are used to obtain the stress-strain increment expression in the plastic zone, including: Based on the hole expansion model, the stress-strain increment matrix in the elastic stage of the plastic zone is obtained using Hooke's law; Based on the pore expansion model, the yield function, hardening law and associated flow law of the modified Cambridge constitutive model are used to obtain the stress-strain increment matrix in the plastic stage of the plastic zone; Using the superposition principle, the stress-strain increment matrix in the elastic stage of the plastic zone and the stress-strain increment matrix in the plastic stage of the plastic zone are superimposed to obtain the initial stress-strain increment matrix in the plastic zone; The initial plastic zone stress-strain increment matrix is ​​subjected to matrix inverse transformation to obtain a plastic zone stress-strain increment expression.

5. The method for calculating the disturbance effect of screw pile installation considering the rotational shear action according to claim 4 is characterized in that: The stress-strain increment expression in the plastic zone satisfies the following formula: ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， in, , and They are simplified symbols of mathematical expressions. is the elastic modulus of the soil, is the compression parameter, is the rebound parameter, is the Poisson's ratio of the soil, is the critical state stress ratio, is the stress ratio, is the mean effective stress, is the effective radial stress, is the effective hoop stress, The effective vertical stress, is the shear stress, is the radial strain, is the hoop strain, is the vertical strain, is the shear strain.

6. The method for calculating the disturbance effect of screw pile installation considering the rotational shear action according to claim 4 is characterized in that: Based on the pore expansion model, the yield function, hardening law and associated flow law of the modified Cambridge constitutive model are used to obtain the stress-strain increment matrix in the plastic stage of the plastic zone, including: Based on the pore expansion model, using the yield function and the associated flow law, an expression for the strain increment in the plastic stage of the plastic zone is obtained; According to the formulas of mean effective stress and generalized shear stress, the mean effective stress differential equation and the generalized shear stress differential equation are obtained; Substituting the hardening law into the strain increment expression of the plastic stage in the plastic zone, and combining the average effective stress differential equation and the generalized shear stress differential equation, to obtain the plasticity factor expression; Substitute the plastic factor expression into the strain increment expression of the plastic stage in the plastic zone to obtain the stress-strain increment matrix of the plastic stage in the plastic zone.

7. The method for calculating the disturbance effect of screw pile installation considering the rotational shear action according to claim 1 is characterized in that: The assumed conditions include an undrained soil condition and a plane strain condition. The step of obtaining the stress distribution in the plastic zone according to the assumed conditions, the stress-strain increment expression in the plastic zone, the stress distribution in the elastic zone, and the displacement in the elastic zone includes: Using the undrained soil condition and the plane strain condition, an expression for strain increment is obtained; Substituting the strain increment expression into the plastic zone stress strain increment expression, a first-order differential equation of the stress component in the radial direction of the screw pile is obtained; Obtaining elastic-plastic boundary stress by using the elastic region stress distribution, the generalized shear stress definition and the yield function; Using the elastic zone displacement and the undrained condition of the soil, the radius of the elastic-plastic boundary is obtained; Substitute the elastic-plastic boundary stress and the radius of the elastic-plastic boundary into the first-order differential equation for iterative solution to obtain the stress distribution in the plastic zone.

8. The method for calculating the disturbance effect of screw pile installation considering rotational shearing according to claim 1 is characterized in that: The stress field and pore water pressure of the surrounding soil during the screw pile rotation installation process are obtained according to the elastic zone stress distribution, the plastic zone stress distribution and the total equilibrium equation, including: Using the elastic region stress distribution, obtaining the elastic region pore water pressure; Integrating the total equilibrium equation to obtain an integral expression of excess pore water pressure in the radial direction of the screw pile; According to the integral expression, the excess pore water pressure is obtained; Superimposing the elastic zone pore water pressure and the excess pore water pressure to obtain the plastic zone pore water pressure; The pore water pressure in the plastic zone, the stress distribution in the elastic zone, the pore water pressure in the elastic zone and the stress distribution in the plastic zone are combined to obtain the stress field and pore water pressure of the surrounding soil during the rotation installation of the screw pile.

9. The method for calculating the disturbance effect of screw pile installation considering the rotational shear action according to claim 1 is characterized in that: The excess pore water pressure satisfies the following formula: ， in, is the excess pore water pressure, is the effective radial stress at the elastic-plastic boundary, is the radial radius associated with the excess pore water pressure, The radius The effective radial stress at is the radius of the elastic-plastic interface, is the effective radial stress, is the effective hoop stress, is the integration variable; The pore water pressure in the plastic zone satisfies the following formula: ， in, is the pore water pressure in the plastic zone, is the pore water pressure in the elastic zone, is the excess pore water pressure.

10. A system for calculating the disturbance effect of screw pile installation based on rotational shearing, characterized in that: include: A processor, an input device, an output device and a memory, wherein the processor, the input device, the output device and the memory are connected to each other, wherein the memory is used to store a computer program, the computer program includes program instructions, and the processor is configured to call the program instructions to execute the method for calculating the disturbance effect of screw pile installation considering the rotational shear effect as described in any one of claims 1 to 9.

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