Calculation method and system for installation disturbance effect of screw pile considering rotational shear action

Abstract

The present invention relates to the technical fields of pile foundation engineering and geotechnical mechanics, specifically a calculation method and system for the installation disturbance effect of a screw pile considering the rotational shear effect. The method includes: establishing a cavity expansion model of the surrounding soil during the rotational installation of the screw pile according to the relevant parameters of the screw pile, the assumed conditions, and the stress boundary conditions; combining the stress boundary conditions, and using the cavity expansion model, the total equilibrium equation, and the stress-strain relationship to obtain the stress distribution in the elastic zone and the displacement in the elastic zone; using the yield function, hardening law, and associated flow rule of the modified Cam clay constitutive model to obtain the expression of the stress-strain increment in the plastic zone; according to the assumed conditions, the expression of the stress-strain increment in the plastic zone, the stress distribution in the elastic zone, and the displacement in the elastic zone, obtaining the stress distribution in the plastic zone; and finally realizing the calculation of the disturbance effect according to the above results. It solves the problem that the calculation of the installation disturbance effect of the screw pile in the prior art is not accurate enough.

Description

Technical Field

[0001] The present invention relates to the technical fields of pile foundation engineering and geotechnical mechanics, and specifically to a calculation method and system for the installation disturbance effect of a screw pile considering the rotational shear effect. Background Art

[0002] With the continuous development of China's economy, newly built large-scale projects have put forward higher requirements for the bearing capacity of pile foundations. As a new type of pile with a special cross-section, the screw pile has been widely used in building construction, wind power generation, retaining and protecting, and offshore oil platforms due to its higher bearing capacity.

[0003] At present, many studies have been carried out on the bearing characteristics of screw piles at home and abroad, but the research on the installation disturbance effect of screw piles considering the rotational shear effect is relatively scarce. During the construction process of screw piles, the torque applied to the top of the pile will cause the pile to rotate into the soil, which will lead to shear stress at the orifice, exert a disturbance effect on the soil around the pile, and thus affect the stress field and pore water pressure of the soil around the pile, which will have an impact on construction safety. However, in the existing technology, most of the calculations of the installation disturbance effect of screw piles do not consider the rotational shear effect, or even if the rotational shear effect is considered, the calculation is not comprehensive enough, resulting in inaccurate calculation of the installation disturbance effect of screw piles. Therefore, it is necessary to propose a calculation method for the installation disturbance effect of screw piles considering the rotational shear effect. This research work not only helps to predict the stress field and pore water pressure of the surrounding soil during the rotational installation of screw piles and improve the theoretical system of screw pile foundations, but also provides a scientific design basis and construction guidance for practical engineering. Summary of the Invention

[0004] Aiming at the defects in the existing technology, the present invention provides a calculation method and system for the installation disturbance effect of a screw pile considering the rotational shear effect, solving the problem of inaccurate calculation of the installation disturbance effect of screw piles in the existing technology.

[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:

[0010] ,

[0011] 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.

[0012] 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.

[0013] 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.

[0014] The present invention obtains the stress-strain increment matrices in the elastic and plastic stages of the plastic zone through Hooke's law and the modified Cam clay constitutive model, fully considering the characteristics of the soil mass at different deformation stages. Then, by the superposition principle, the matrices of the two stages are integrated to obtain the initial stress-strain increment matrix of the plastic zone, comprehensively covering the comprehensive mechanical response of the soil mass from elastic to plastic transition. Finally, matrix inverse transformation is performed to obtain the final expression, improving the accuracy of analyzing the mechanical behavior of the soil mass in the plastic zone, helping to deeply understand the disturbance of the surrounding plastic zone soil mass during the installation of the screw pile, and thus providing a strong basis for optimizing the screw pile design and ensuring the safety and stability of the project.

[0015] Optionally, the stress-strain increment expression of the plastic zone satisfies the following formula:

[0016] ,

[0017] ,

[0018] ,

[0019] ,

[0020] ,

[0021] ,

[0022] ,

[0023] ,

[0024] ,

[0025] ,

[0026] ,

[0027] ,

[0028] ,

[0029] ,

[0030] ,

[0031] ,

[0032] ,

[0033] Wherein, 、 And They are all symbols for simplifying mathematical expressions, is the elastic modulus of the soil mass, is the compression parameter, is the rebound parameter, is the Poisson's ratio of the soil mass, is the critical state stress ratio, is the stress ratio, is the mean effective stress, is the effective radial stress, is the effective circumferential stress, Effective vertical stress, is the shear stress, is the radial strain, is the circumferential strain, is the vertical strain, is the shear strain.

[0034] The parameter combinations of the stress-strain increment expression in the plastic zone of the present invention accurately describe the stress-strain relationship in the plastic zone, providing a quantitative tool for the mechanical analysis of the soil around the screw pile. Key parameters such as the elastic modulus and Poisson's ratio are incorporated, enabling comprehensive consideration of the influence of soil material properties on the mechanical response and improving the calculation accuracy. Based on this expression, the stress-strain changes in the plastic zone of the soil can be analyzed in depth, helping to evaluate the disturbance of the surrounding soil during the installation of the screw pile, providing strong support for the design and construction of the pile foundation project, and improving the accuracy of the calculation of the stress-strain increment in the plastic zone.

[0035] Optionally, based on the hole expansion model, using the yield function, hardening law, and associated flow rule of the modified Cam clay constitutive model, the stress-strain increment matrix in the plastic stage of the plastic zone is obtained as follows: Based on the hole expansion model, using the yield function and the associated flow rule, the strain increment expression in the plastic stage of the plastic zone is obtained; According to the formulas of the mean effective stress and the generalized shear stress, the mean effective stress differential equation and the generalized shear stress differential equation are obtained; Substitute the hardening law into the strain increment expression in the plastic stage of the plastic zone, and combine the mean effective stress differential equation and the generalized shear stress differential equation to obtain the plastic factor expression; Substitute the plastic factor expression into the strain increment expression in the plastic stage of the plastic zone to obtain the stress-strain increment matrix in the plastic stage of the plastic zone.

[0036] The present invention obtains the strain increment expression in the plastic stage by using the yield function and the associated flow rule, which accurately reflects the internal relationship between stress and strain increment during the plastic deformation of the soil mass, laying a foundation for in-depth analysis of the plastic behavior of the soil mass. The plastic factor expression is obtained through the hardening law and the strain increment expression in the plastic stage, effectively considering the hardening characteristics of the soil mass during the plastic deformation process, that is, the changes in the strength and stiffness of the soil mass as the deformation develops. Substituting the plastic factor expression back into the strain increment expression to obtain the stress-strain increment matrix comprehensively synthesizes various mechanical properties of the soil mass, enabling this matrix to more accurately describe the mechanical response of the soil mass in the plastic zone under complex stress states. It can provide more reliable data for engineers, helping them optimize the design and construction plans of screw piles, and improving the stability and safety of the project.

[0037] Optionally, obtaining the stress distribution in the plastic zone according to the assumption 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: obtaining the strain increment expression by using the undrained condition of the soil mass and the plane strain condition; substituting the strain increment expression into the stress-strain increment expression in the plastic zone to obtain a first-order differential equation of the stress component with respect to the radial direction of the screw pile; obtaining the elastic-plastic boundary stress by using the stress distribution in the elastic zone, the definition of the generalized shear stress, and the yield function; obtaining the radius of the elastic-plastic boundary by using the displacement in the elastic zone and the undrained condition of the soil mass; 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.

[0038] The present invention obtains the strain increment expression by means of the undrained condition of the soil mass and the plane strain condition, which closely conforms to the drainage and deformation states of the soil mass in actual engineering, providing basic data that conforms to the actual situation for subsequent calculations. Substituting it into the stress-strain increment expression in the plastic zone to obtain a first-order differential equation, transforming the complex stress-strain relationship into a mathematical form that is convenient for solution. Determining the elastic-plastic boundary stress through the stress distribution in the elastic zone, the definition of the generalized shear stress, and the yield function, and combining the displacement in the elastic zone and the undrained condition of the soil mass to obtain the radius of the elastic-plastic boundary, accurately defining the boundary conditions for calculating the plastic zone. Finally, substituting the elastic-plastic boundary stress and the radius into the first-order differential equation for iterative solution can accurately obtain the stress distribution in the plastic zone. It not only helps to deeply understand the stress change law of the soil mass in the plastic zone during the installation process of screw piles, but also provides a key basis for evaluating the bearing capacity and stability of screw piles, thereby optimizing the design parameters and construction technology of screw piles, improving the project quality, and reducing the project risk.

[0039] Optionally, 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 includes: obtaining the pore water pressure in the elastic zone using the elastic zone stress distribution; integrating the total equilibrium equation to obtain an integral expression of the excess pore water pressure with respect to 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 elastic zone stress distribution, the pore water pressure in the elastic zone, and the plastic zone stress distribution to obtain the stress field and pore water pressure of the surrounding soil during the rotational installation of the screw pile.

[0040] The present invention obtains the pore water pressure in the elastic zone from the elastic zone stress distribution, providing basic data for the overall calculation and reasonably reflecting the situation of the pore water pressure in the soil during the elastic stage. Integrating the total equilibrium equation to obtain the integral expression of the excess pore water pressure, and then obtaining the excess pore water pressure, effectively considering the change in pore water pressure caused by factors such as soil deformation during the installation of the screw pile. 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, comprehensively covering the influencing factors of pore water pressure in different stages. Combining the pore water pressure in the plastic zone, the stress distributions in the elastic and plastic zones, 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 screw pile installation on the stability of the surrounding soil, further improving the accuracy of calculating the disturbance effect of screw pile installation.

[0041] Optionally, the excess pore water pressure satisfies the following formula:

[0042] ,

[0043] where, is the excess pore water pressure, is the effective radial stress at the elastic-plastic boundary, is the radial radius related to the excess pore water pressure, is the radius at which the effective radial stress is located, is the radius of the elastic-plastic interface, is the effective radial stress, is the effective circumferential stress, is the integration variable.

[0044] The pore water pressure in the plastic zone satisfies the following formula:

[0045] ,

[0046] Among them, is the pore water pressure in the plastic zone, is the pore water pressure in the elastic zone, is the excess pore water pressure.

[0047] 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 during the installation of the screw pile. On this basis, the pore water pressure formula in the plastic zone combines the pore water pressure in the elastic zone to completely obtain the pore water pressure in the plastic zone, improving the calculation accuracy.

[0048] Another aspect of the present invention provides a calculation system for the installation disturbance effect of a screw pile based on rotational shear action, including: a processor, an input device, an output device, and a memory. The processor, the input device, the output device, and the memory are interconnected. Among them, 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 calculation methods for the installation disturbance effect of the screw pile considering rotational shear action provided in the previous aspect of the present invention.

[0049] The calculation system for the installation disturbance effect of a screw pile based on rotational shear action of the present invention has a compact structure, stable performance, high integration, and simple composition, and can stably execute the calculation method for the installation disturbance effect of the screw pile considering rotational shear action provided in the previous aspect of the present invention, further improving the overall applicability and practical application ability of the present invention. Description of the Drawings

[0050] Figure 1 is a flowchart of the calculation method for the installation disturbance effect of a screw pile considering rotational shear action according to an embodiment of the present invention;

[0051] Figure 2 is a sectional view of the screw pile and the hole expansion model in the calculation method for the installation disturbance effect of a screw pile considering rotational shear action according to an embodiment of the present invention;

[0052] Figure 3 is a schematic structural diagram of the calculation system for the installation disturbance effect of a screw pile based on rotational shear action according to an embodiment of the present invention. Detailed Embodiments

[0053] The specific embodiments of the present invention will be described in detail below. It should be noted that the embodiments described here are only for illustrative purposes and are not used to limit the present invention. In the following description, in order to provide a thorough understanding of the present invention, a large number of specific details are set forth. However, it is obvious to those of ordinary skill in the art that: it is not necessary to adopt these specific details to implement the present invention. In other instances, well-known circuits, software, or methods are not specifically described to avoid obscuring the present invention.

[0054] Throughout the specification, references to "one embodiment", "an embodiment", "one example" or "an example" mean that a particular feature, structure, or characteristic described in connection with the embodiment or example is included in at least one embodiment of the present invention. Thus, the phrases "in one embodiment", "in an embodiment", "one example" or "an example" that appear throughout the specification do not necessarily all refer to the same embodiment or example. In addition, the particular features, structures, or characteristics may be combined in any suitable combination and / or sub-combination in one or more embodiments or examples. Furthermore, those of ordinary skill in the art should understand that the diagrams provided herein are for illustrative purposes only and are not necessarily drawn to scale.

[0055] Figure 1 The following is a flowchart of a calculation method for the installation disturbance effect of a screw pile considering the rotational shear effect according to an embodiment of the present invention. This method solves the problem that the calculation of the installation disturbance effect of a screw pile in the prior art is not accurate enough, as Figure 1 shown in the method, which includes the following steps:

[0056] Step S1, set the assumed conditions and stress boundary conditions, and establish a cavity expansion model of the surrounding soil during the rotational installation of the screw pile according to the relevant parameters of the screw pile, the assumed conditions, and the stress boundary conditions.

[0057] In this embodiment, the screw pile and the cavity expansion model are as Figure 2 shown. A circular hole with an initial radius of is located in an infinite isotropic soil mass, and the initial stress of the soil is (at infinity). A uniformly distributed radial pressure and shear stress (as defined in the present invention , where b is a value between 0 and 1 reflecting the magnitude of the shear stress, and is the undrained shear strength of the soil) act at the hole opening. The hole expands from the initial radius to the radius under the external action. The radius of the elastic-plastic interface is , the displacement at the elastic-plastic interface is , and the initial pore water pressure is .

[0058] For the convenience and feasibility of calculation, assumed conditions and boundary conditions are proposed.

[0059] The assumed conditions are satisfied:

[0060] (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 Cam clay constitutive model.

[0061] (2) The hole expansion process conforms to the plane strain model.

[0062] (3) The soil is undrained, that is, the volume strain is 0.

[0063] (4) The small deformation assumption is used in the elastic zone, and the large strain assumption is used in the plastic zone.

[0064] The boundary conditions are met:

[0065] (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.

[0066] (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.

[0067] 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.

[0068] 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.

[0069] 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:

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] like Figure 2 For the pore expansion model shown in the figure, the overall equilibrium equation satisfies the following formula:

[0075] ,

[0076] 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.

[0077] The radial strain, hoop strain and shear strain can be expressed as:

[0078] ,

[0079] ,

[0080] ,

[0081] 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.

[0082] Due to the uniform radial pressure and shear stress applied at the orifice, the derivative of its displacement with respect to the angle is 0, that is and , so the above formula can be simplified to:

[0083] ,

[0084] ,

[0085] ,

[0086] Substitute and eliminate to get:

[0087] ,

[0088] Since the soil mass is in the elastic zone, its stress-strain relationship is in the following form:

[0089] ,

[0090] ,

[0091] ,

[0092] ,

[0093] ,

[0094] where is the elastic modulus of the soil mass, is the Poisson's ratio of the soil mass, is the shear modulus.

[0095] Combining the total equilibrium equation, the stress-strain relationship, and the deformation compatibility equation, the stress expression in the radial direction of the screw pile can be obtained, and the stress expression satisfies the following formula:

[0096] ,

[0097] ,

[0098] ,

[0099] where and are integration constants, and their values can be obtained through stress boundary conditions.

[0100] Step S202, substitute the stress boundary conditions into the stress expression to obtain the stress distribution in the elastic zone.

[0101] In this embodiment, after obtaining the stress expression in the radial direction of the screw pile, the stress boundary conditions play a crucial constraining role. The stress boundary conditions define the stress state on the model boundary, such as the stress value on the pile hole surface and the stress condition of the soil mass at infinity.

[0102] Substituting these boundary conditions into the stress expression is actually to determine specific parameters and ranges for the stress expression. In the elastic region, the soil mass follows the laws of elasticity mechanics, and the stress and strain are linearly related. By substituting the boundary conditions, the unknown constants in the stress expression can be eliminated, thus obtaining the stress distribution in the elastic region that conforms to the actual physical situation.

[0103] This stress distribution in the elastic region reflects the stress magnitude and variation law at different positions when the surrounding soil mass is in the elastic deformation stage during the rotary installation of the screw pile. It has important guiding significance for analyzing the interaction between the screw pile and the soil mass, evaluating the stability of the soil mass, and further optimizing the design and construction technology of the screw pile.

[0104] The stress boundary given by the present invention can be expressed as:

[0105] When At this time ;

[0106] When At this time ;

[0107] When At this time ;

[0108] When At this time .

[0109] Using the given stress boundary conditions, the stress formula in the elastic region can be obtained, and its derivation is as follows:

[0110] ,

[0111] ,

[0112] ,

[0113] ,

[0114] Considering that the subsequent derivation needs to involve the stress on the elastic-plastic boundary surface, the stress formula in the elastic region adopts the stress expression form of the elastic-plastic boundary surface, and is in the following form:

[0115] ,

[0116] ,

[0117] ,

[0118] That is, the stress distribution in the elastic region satisfies the following formula:

[0119] ,

[0120] 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.

[0121] Step S203, obtaining elastic region displacement according to the elastic region stress distribution.

[0122] 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.

[0123] The radial displacement can be expressed as:

[0124] ,

[0125] The shear strain can be obtained by combining the stress-strain relationship. Substituting the shear strain into the simplified shear strain equation yields:

[0126] ,

[0127] Integrating the above equation yields:

[0128] ,

[0129] Let the circumferential displacement at the orifice be (mainly radial displacement), and substitute it into the above equation to obtain a new expression:

[0130] ,

[0131] ,

[0132] Among them, is the radial displacement, is the stress difference between the radial stress at the elastoplastic boundary and the initial stress, is the radius of the elastoplastic boundary, is the radial stress at the elastoplastic boundary, is the shear modulus, , is the radial radius, is the circumferential displacement, is the circumferential displacement at the orifice, L is the integration constant, is the radius after hole expansion, is a value reflecting the magnitude of the shear stress between 0 and 1, is the undrained shear strength of the soil mass.

[0133] Step S3, based on the hole expansion model, using the yield function, hardening law and associated flow rule of the modified Cambridge constitutive model, obtain the expression of the stress-strain increment in the plastic zone.

[0134] Among them, the specific steps of obtaining the expression of the stress-strain increment in the plastic zone by using the yield function, hardening law and associated flow rule of the modified Cambridge constitutive model based on the hole expansion model are as follows:

[0135] Step S301, based on the hole expansion model, use Hooke's law to obtain the stress-strain increment matrix in the elastic stage of the plastic zone.

[0136] In this embodiment, the modified Cambridge constitutive model is used to describe the stress-strain in the plastic zone of the soil around the screw pile. 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.

[0137] Hooke's law can describe the linear relationship between stress and strain within the elastic range of materials. By applying this law, the stress applied to the soil mass is related to the generated strain increment. Through a series of mathematical derivations and calculations, the stress-strain increment matrix in the elastic stage of the plastic zone is finally obtained. This matrix quantitatively shows the relationship between the stress and strain increment of the soil mass in the elastic stage of the plastic zone.

[0138] The stress-strain increment matrix in the elastic stage of the plastic zone satisfies the following formula:

[0139] ,

[0140] Among them, 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 mass, is the radial effective stress increment in the elastic stage of the plastic zone, is the circumferential effective stress increment in the elastic stage of the plastic zone, is the vertical effective stress increment in the elastic stage of the plastic zone.

[0141] From the definition of the mean effective stress, we can get:

[0142] ,

[0143] Substituting this equation into the above matrix equation, we can get:

[0144] ,

[0145] Since the volume strain increment is 0 under undrained conditions, the differential of the mean effective stress can be obtained:

[0146] ,

[0147] where, is the mean effective stress, is the effective radial stress, is the effective circumferential stress, effective vertical stress, is the volume strain increment.

[0148] Step S302: Based on the hole expansion model, using the yield function, hardening law, and associated flow rule of the modified Cam clay constitutive model, obtain the stress-strain increment matrix in the plastic stage of the plastic zone.

[0149] Among them, the specific steps of obtaining the stress-strain increment matrix in the plastic stage of the plastic zone based on the hole expansion model and using the yield function, hardening law, and associated flow rule of the modified Cam clay constitutive model are as follows:

[0150] Step S30201: Based on the hole expansion model, using the yield function and the associated flow rule, obtain the strain increment expression in the plastic stage of the plastic zone.

[0151] In this embodiment, the yield function defines the condition for the soil to enter plastic deformation, and the associated flow rule establishes the relationship between the plastic strain increment and the stress. Based on these theories, through mathematical derivation, the strain increment corresponding to each stress component is determined, and finally the expression of the strain increment in the plastic stage of the plastic zone is obtained. This expression lays the foundation for the subsequent analysis of the mechanical behavior of the soil in the plastic zone.

[0152] The yield function of the Modified Cam clay constitutive model is as follows:

[0153] ,

[0154] The definition of the generalized shear stress q is as follows:

[0155] ,

[0156] According to the associated flow rule, the strain increment corresponding to each stress component can be determined, and its expression is as follows:

[0157] ,

[0158] ,

[0159] ,

[0160] ,

[0161] Therefore, the expression of the strain increment in the plastic stage satisfies the following formula:

[0162] ,

[0163] ,

[0164] ,

[0165] ,

[0166] Among them, is the hardening parameter, M is the critical state stress ratio, q is the generalized shear stress, is the mean effective stress, , , and respectively represent the strain increments in the radial, circumferential, vertical, and shear directions in the plastic stage of the plastic zone, is the plastic factor, and its expression can be obtained by using the hardening law of the Modified Cam clay model, is the effective radial stress, is the effective circumferential stress, effective vertical stress, is the shear stress.

[0167] Step S30202: Obtain the differential equation of the mean effective stress and the differential equation of the generalized shear stress according to the formulas of the mean effective stress and the generalized shear stress.

[0168] In this embodiment, the mean effective stress and the generalized shear stress are important parameters for analyzing the stress state of soil. Based on the formulas of these two parameters, through mathematical derivation and transformation, the differential equation of the mean effective stress and the differential equation of the generalized shear stress are obtained. The formula of the mean effective stress is a comprehensive calculation of each stress component, and the formula of the generalized shear stress is used to measure the intensity of the shear action on the soil. By differentiating them, the laws of the mean effective stress and the generalized shear stress changing with the stress components are revealed.

[0169] The formula of the mean effective stress is as follows:

[0170] ,

[0171] Thus, the differential equation of the mean effective stress can be obtained as:

[0172] ,

[0173] The formula of the generalized shear stress is as follows:

[0174] ,

[0175] Thus, the differential equation of the generalized shear stress can be obtained as:

[0176] ,

[0177] where, is the mean effective stress, is the effective radial stress, is the effective circumferential stress, effective vertical stress, is the stress component, is the Kronecker symbol, is the generalized shear stress, is the shear stress.

[0178] Step S30203: Substitute the hardening law into the strain increment expression in the plastic stage of the plastic zone, and combine the differential equation of the mean effective stress and the differential equation of the generalized shear stress to obtain the plastic factor expression.

[0179] In this embodiment, the hardening law describes the variation characteristics of the strength and stiffness of soil during plastic deformation, providing a basis for studying the variation of the soil's own properties. At the same time, combined with the differential equation of the mean effective stress and the differential equation of the generalized shear stress, these two equations reflect the laws of the mean effective stress and the generalized shear stress varying with the stress components. By combining these three, a series of mathematical operations and derivations are carried out, fully considering the mutual relationship among the soil stress change, deformation characteristics, and the change of its own properties, and finally the expression of the plastic factor is obtained.

[0180] According to the hardening law, it can be obtained that:

[0181] ,

[0182] ,

[0183] where e is the void ratio, is the compression parameter, is the rebound parameter, is a symbol defined for simplifying the mathematical expression, and other variables are defined as above.

[0184] The hardening parameter can be expressed as:

[0185] ,

[0186] The differentials of the mean effective stress and the generalized shear stress are respectively expressed as:

[0187] ,

[0188] ,

[0189] Substitute the hardening law into the associated flow rule equation and combine the differentials of the mean effective stress and the generalized shear stress to obtain the expression of:

[0190] ,

[0191] ,

[0192] ,

[0193] ,

[0194] where, is the stress ratio, M is the critical state stress ratio, q is the generalized shear stress, and are both symbols defined for simplifying the mathematical expression, and other variables are defined as above.

[0195] Step S30204: Substitute the plastic factor expression into the plastic zone plastic stage strain increment expression to obtain the plastic zone plastic stage stress-strain increment matrix.

[0196] In this embodiment, the plastic factor expression reflects the characteristic parameters related to the hardening law, mean effective stress, and generalized shear stress of the soil during plastic deformation. The plastic zone plastic stage strain increment expression describes the strain increment relationship corresponding to each stress component in the plastic stage. Substituting the plastic factor expression into the plastic zone plastic stage strain increment expression, through the subsequent mathematical operations and arrangements, comprehensively considering the mutual relationship of each stress-strain factor of the soil during the plastic deformation stage, finally obtain the plastic zone plastic stage stress-strain increment matrix. This matrix can more comprehensively and accurately describe the quantitative relationship between stress and strain increment of the soil in the plastic zone under complex stress states.

[0197] The plastic zone plastic stage stress-strain increment matrix satisfies the following formula:

[0198] ,

[0199] ,

[0200] ,

[0201] ,

[0202] ,

[0203] ,

[0204] Step S303: Using the superposition principle, superimpose the plastic zone elastic stage stress-strain increment matrix and the plastic zone plastic stage stress-strain increment matrix to obtain the initial plastic zone stress-strain increment matrix.

[0205] In this embodiment, the superposition principle is used in mechanical analysis to synthesize multiple related matrices to obtain more comprehensive mechanical information. Superimposing the above two matrices integrates the stress-strain increment characteristics of the soil in the elastic and plastic stages, eliminates the isolation of different stage analyses, and thus obtains 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 to the plastic stage. This new matrix covers the comprehensive information of the stress-strain increment of the soil in these two stages.

[0206] The initial plastic zone stress-strain increment matrix satisfies the following formula:

[0207] ,

[0208] Among them, , , and represent radial, circumferential, vertical, and shear strains respectively, S, , , and are symbols defined for simplifying mathematical expressions, and other variables are defined as above.

[0209] Step S304: Perform a matrix inverse transformation on the initial plastic zone stress-strain increment matrix to obtain the plastic zone stress-strain increment expression.

[0210] In this embodiment, to study the variation law of the stress and strain of the soil in the plastic zone more deeply, the strain increment needs to be regarded as a known quantity to solve the expression of the stress increment. Therefore, a mathematical method of matrix inverse transformation is used to process the initial plastic zone stress-strain increment matrix. Matrix inverse transformation is a linear algebra operation that can recombine the elements in the matrix to achieve the conversion from strain increment to stress increment.

[0211] After the matrix inverse transformation, the plastic zone stress-strain increment expression is successfully obtained. This expression can more directly reflect the quantitative relationship between the stress and strain increment of the soil in the plastic zone during the installation of the screw pile, providing a key quantitative basis for accurately analyzing the disturbance effect of the screw pile installation on the surrounding plastic zone soil.

[0212] The plastic zone stress-strain increment expression satisfies the following formula:

[0213] ,

[0214] ,

[0215] ,

[0216] ,

[0217] ,

[0218] ,

[0219] ,

[0220] ,

[0221] ,

[0222] ,

[0223] ,

[0224] ,

[0225] ,

[0226] ,

[0227] ,

[0228] ,

[0229] ,

[0230] Among them, 、 and are all symbols for simplifying mathematical expressions. is the elastic modulus of the soil mass. is the compression parameter. is the rebound parameter. is the Poisson's ratio of the soil mass. is the critical state stress ratio. is the stress ratio. is the mean effective stress. is the effective radial stress. is the effective circumferential stress. Effective vertical stress is the shear stress. is the radial strain. is the circumferential strain. is the vertical strain. is the shear strain.

[0231] Step S4: Obtain 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.

[0232] Among them, 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 specifically includes the following sub-steps:

[0233] Step S401: Obtain the strain increment expression by using the undrained condition of the soil mass and the plane strain condition.

[0234] In this embodiment, the undrained condition of the soil mass means that the volume of the soil mass does not change during the whole process, that is, the volume strain is 0, and the plane strain condition stipulates that the strain increment in a certain direction of the soil mass is 0. Combining with relevant theoretical knowledge such as logarithmic strain, through mathematical derivation and analysis, the strain increment expression is finally obtained.

[0235] In this embodiment, due to the undrained condition of the soil, the volume of the soil will not change, that is:

[0236] ,

[0237] According to the plane strain assumption, that is:

[0238] ,

[0239] Using logarithmic strain, the strain increment expression satisfies the following expression:

[0240] ,

[0241] The variable definitions are the same as above.

[0242] 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.

[0243] 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.

[0244] The first-order differential equation satisfies the following formula:

[0245] ,

[0246] ,

[0247] ,

[0248] ,

[0249] Step S403, obtaining elastic-plastic boundary stress by using the elastic region stress distribution, the definition of generalized shear stress and the yield function.

[0250] 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.

[0251] In this embodiment, the effective radial and hoop stresses at infinity are defined as:

[0252] ,

[0253] is the effective radial stress at infinity, is the effective circumferential stress at infinity.

[0254] The soil at the elastoplastic boundary reaches the yield state. According to the yield equation, the elastoplastic boundary stresses satisfy the following relationship:

[0255] ,

[0256] where, is the generalized shear stress at the elastoplastic boundary, is the average effective stress at the elastoplastic interface, is the maximum preconsolidation pressure, and the other variables are defined as above.

[0257] Since the effective stress remains unchanged in the elastic stage, the generalized shear stress at the elastoplastic boundary satisfies the following expression:

[0258] ,

[0259] ,

[0260] ,

[0261] ,

[0262] where, is the overconsolidation ratio, is the initial average effective stress.

[0263] According to the definition of the generalized shear stress, another expression is as follows:

[0264] ,

[0265] Since the stress at the elastoplastic interface follows the stress formula in the elastic region, the following relationship can be obtained:

[0266] ,

[0267] Combining the above formulas, we can get:

[0268] ,

[0269] ,

[0270] where, is the effective radial stress at the elastoplastic boundary, is the effective circumferential stress at the elastoplastic boundary, is the shear stress at the elastoplastic interface, which can be obtained from the stress expression in the elastic region. is the effective radial stress at infinity. is the effective circumferential stress at infinity. The definitions of other variables are the same as above.

[0271] Step S404: Use the displacement in the elastic region and the undrained condition of the soil to obtain the radius of the elastoplastic boundary.

[0272] In this embodiment, it can be seen from the elastic region displacement formula that it is related to the stress and radius at the elastoplastic boundary. At the same time, the undrained condition of the soil makes the soil volume unchanged, and thus an equation of the relationship between the radii can be established. Substitute the elastic region displacement formula into the equation obtained from the undrained condition of the soil, and through mathematical transformation and derivation, other variables are gradually eliminated, and finally an expression for the radius of the elastoplastic boundary is obtained. The determination of the radius of the elastoplastic boundary is a key link for accurately calculating the stress distribution in the plastic region and deeply studying the installation disturbance effect of the screw pile, providing important basic data for the entire research.

[0273] From the elastic region displacement formula:

[0274] ,

[0275] Due to the undrained condition of the soil, the soil volume remains unchanged during the whole process, so the following relational expression holds:

[0276] ,

[0277] Substituting the elastic region displacement formula gives:

[0278] ,

[0279] Substitute into the above formula to get The expression of is as follows:

[0280] ,

[0281] where is the current radial radius, is the initial radial radius, is the radius when the soil immediately yields, is the radius of the elastoplastic interface, Initial radius of the hole, is the radius after the hole expands. The definitions of other variables are the same as above.

[0282] Step S405: Substitute the stress at the elastoplastic boundary and the radius of the elastoplastic boundary into the first-order differential equation for iterative solution to obtain the stress distribution in the plastic region.

[0283] In this embodiment, substituting the elastoplastic boundary stress and the radius into the first-order differential equation combines the boundary conditions with the stress change equation. Since this equation is difficult to solve directly, an iterative algorithm is adopted. The iterative algorithm continuously repeats calculations, updates parameters based on the previous calculation results each time, and gradually approaches the true solution. During multiple iterations, the calculation parameters are continuously adjusted until the calculation results meet the preset accuracy requirements, and finally the accurate stress distribution in the plastic zone is obtained.

[0284] Step S5: Obtain the stress field and pore water pressure of the surrounding soil during the rotary installation of the screw pile according to the elastic zone stress distribution, the plastic zone stress distribution, and the total equilibrium equation.

[0285] Among them, obtaining the stress field and pore water pressure of the surrounding soil during the rotary installation of the screw pile according to the elastic zone stress distribution, the plastic zone stress distribution, and the total equilibrium equation specifically includes the following sub-steps:

[0286] Step S501: Obtain the pore water pressure in the elastic zone by using the elastic zone stress distribution.

[0287] In this embodiment, based on the elastic zone stress distribution and combined with the effective stress principle, when the total stress distribution in the elastic zone is known and the average effective stress is determined to be constant, the pore water pressure in the elastic zone can be deduced. First, determine the total stress at each point in the elastic zone, and then calculate the corresponding pore water pressure value at each point according to 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 zone.

[0288] Step S502: Integrate the total equilibrium equation to obtain the integral expression of the excess pore water pressure in the radial direction of the screw pile.

[0289] In this embodiment, integrating the total equilibrium equation is a key step in obtaining the integral expression of the excess pore water pressure in the radial direction of the screw pile. The total equilibrium equation describes the stress equilibrium relationship in the soil body and reflects the connection between the effective radial stress, the effective circumferential stress, the pore water pressure, and the shear stress, etc. When integrating the total equilibrium equation, the different characteristics and boundary conditions of the soil body need to be considered.

[0290] During the integration process, the integration constants need to 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, the relationship between each stress component and the position variable in the radial direction of the screw pile can be established, and finally the integral expression of the excess pore water pressure with respect to the radial direction of the screw pile can be obtained, clearly showing the variation trend of the excess pore water pressure with the radial distance. This expression provides a powerful mathematical basis for further studying the variation law of pore water pressure in the soil during the installation of the screw pile, and is of great significance for evaluating the disturbance effect of the screw pile installation on the surrounding soil.

[0291] Step S503, obtain the excess pore water pressure according to the integral expression.

[0292] In this embodiment, the integral expression is derived by comprehensively considering factors such as the soil stress equilibrium relationship, stress-strain characteristics, and boundary conditions, and it contains the mathematical relationship between the 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, using mathematical calculation methods to solve this expression can obtain the specific values of the excess pore water pressure at different radial positions.

[0293] The excess pore water pressure satisfies the following formula:

[0294] ,

[0295] where, is the excess pore water pressure, is the effective radial stress at the elastoplastic boundary, is the radial radius related to the excess pore water pressure, is the radius where the effective radial stress is located, is the radius of the elastoplastic interface, is the effective radial stress, is the effective circumferential stress, is the integration variable.

[0296] Step S504, superimpose the pore water pressure in the elastic zone and the excess pore water pressure to obtain the pore water pressure in the plastic zone.

[0297] In this embodiment, superimposing the pore water pressure in the elastic zone and the excess pore water pressure is based on the continuity and superposition of the pore water pressure change during the transition of the soil from the elastic state to the plastic state. Through this superposition operation, the elastic stage and the additional influence caused by the installation of the screw pile can be comprehensively considered, so as 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.

[0298] The pore water pressure in the plastic zone satisfies the following formula:

[0299] ,

[0300] where, is the pore water pressure in the plastic zone, is the pore water pressure in the elastic zone, is the excess pore water pressure.

[0301] Step S505: Combine 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.

[0302] In this embodiment, the pore water pressure in the plastic zone reflects the change of pore water pressure in the plastic deformation region. It is obtained by superimposing the excess pore water pressure and the pore water pressure in the elastic zone, and reflects the characteristics of pore water pressure in the plastic deformation stage of the soil. The stress distribution in the elastic zone shows the stress state of the soil far from the screw pile area and 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 region, and the stress distribution in the plastic zone details the stress conditions of the soil in the directly affected area around the screw pile. It reflects the redistribution and adjustment of stress during the plastic deformation of the soil and is crucial for understanding the pile-soil interaction mechanism. When combining these data, starting from the stress distribution in the elastic zone and combining the stress distribution in the plastic zone, the transition and change laws 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, the magnitude and direction of stress at different positions of the surrounding soil during the rotational installation of the screw pile, as well as the specific values of the pore water pressure, can be completely depicted.

[0303] As Figure 3 shown, the present invention also provides a calculation system for the installation disturbance effect of a screw pile based on rotational shear action, including: a processor, an input device, an output device, and a memory. The processor, the input device, the output device, and the memory are interconnected. Among them, 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 embodiments in the calculation method for the installation disturbance effect of a screw pile considering rotational shear action in the previous aspect of the present invention.

[0304] For the calculation system of the installation disturbance effect of the screw pile based on the rotary shearing action provided by the present invention, each functional component can be integrated in one processing component, or each component can exist physically alone, or two or more components can be integrated in 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.

[0305] 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 them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered by the scope of the claims and the description 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; 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; 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; According to the stress distribution in the elastic zone, the displacement in the elastic zone is obtained; 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; The assumptions include undrained soil conditions and plane strain conditions; 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; Substituting the elastic-plastic boundary stress and the radius into the first-order differential equation for iterative solution to obtain the stress distribution in the plastic zone; 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.

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: 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 stress-strain increment matrix of the plastic stage in the plastic zone is obtained by using the yield function, hardening law and associated flow law of the modified Cambridge constitutive model; 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.

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-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.

4. The method for calculating the disturbance effect of screw pile installation considering the rotational shear action according to claim 2 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.

5. 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.

6. 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 5.

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