A dynamic calculation method of anchor chair pile considering soil-structure interaction

Abstract

The application discloses a kind of anchor cable chair type pile dynamic calculation method considering soil-structure interaction, comprising the following steps: S1: establishing the dynamic balance differential equation considering anchor cable-chair type pile-soil interaction, and the difference considering chair type pile and front and rear soil interaction is realized by means of symbolic function;S2: according to stress balance and deformation continuity, the boundary condition of dynamic balance differential equation is given;S3: according to initial time displacement and velocity, the initial condition of dynamic balance differential equation is given;S4: the dynamic balance differential equation is solved in combination with boundary and initial conditions, and the distribution function of acceleration, displacement and bending moment of each part of anchor cable chair type pile under seismic action and the axial force function of anchor cable are obtained;S5: according to the function obtained in step S4, the deformation and stress of chair type pile at different times are obtained.The application can accurately calculate the deformation and stress of anchor cable chair type pile under dynamic action, and provides a theoretical basis for dynamic analysis and seismic design of anchor cable chair type pile.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of anchor cable chair pile dynamic calculation method, and particularly relates to an anchor cable chair pile dynamic calculation method considering soil-structure interaction. BACKGROUND

[0002] As one of the most destructive secondary disasters in earthquakes, earthquake landslide has caused great loss to ecological environment, infrastructure and life safety. In order to effectively improve the stability of these slopes, in recent years, traditional supporting and retaining structure types such as anti-slide pile, anchor anti-slide pile and anchor beam have been formed, but it is difficult to meet the actual needs of aseismic reinforcement of high and steep slopes in strong earthquake areas. In order to effectively solve the aseismic reinforcement problem of high and steep slopes in strong earthquake areas, anchor cable chair pile structure emerges as the times require.

[0003] At present, the analysis and calculation of anchor cable chair pile mainly adopts static method, and the method for aseismic design mainly adopts pseudo-static method based on static method. The method is reasonable for static analysis, but for dynamic analysis, the method is too simplified. This is because in the traditional method, the seismic action is regarded as an inertial force added to the structure, and the seismic motion characteristics are not involved. The seismic wave propagates from the earthquake source to the structure through the slope rock-soil body, causing vibration of the structure, and the inertial force generated by the structure vibration acts on the rock-soil body in turn. Due to the differences in material characteristics of the slope rock-soil body, reinforced structure and anchor cable, the stress characteristics and interaction are also obviously different, so the interaction among anchor cable-chair pile-rock-soil body must be considered under the action of earthquake. SUMMARY

[0004] In view of the above problems, the present application aims to provide an anchor cable chair pile dynamic calculation method considering soil-structure interaction.

[0005] The technical scheme of the present application is as follows:

[0006] An anchor cable chair pile dynamic calculation method considering soil-structure interaction, comprising the following steps:

[0007] S1: based on d'Alembert's principle, a dynamic balance differential equation considering the interaction among anchor cable-chair pile-rock-soil body is established, and when the dynamic balance differential equation is established, the difference in interaction between the chair pile and the front and rear soil bodies is realized by means of a sign function;

[0008] S2: according to force balance and deformation continuity, the boundary conditions of the dynamic balance differential equation are given;

[0009] S3: according to the initial displacement and initial velocity, the initial conditions of the dynamic balance differential equation are given;

[0010] S4: solving the dynamic equilibrium differential equation in combination with the boundary conditions and the initial conditions to obtain the distribution functions of acceleration, displacement, and bending moment of each part of the anchor chair pile under earthquake action and the axial force function of the anchor cable;

[0011] S5: Calculate the acceleration, displacement, bending moment and axial force at different times according to the function obtained in step S4.

[0012] Preferably, in step S1, the dynamic equilibrium differential equation includes:

[0013] (1) Dynamic equilibrium differential equation below the pile foundation rock:

[0014] (1)

[0015] Where: is the elastic modulus of the chair pile; is the moment of inertia of the rear pile; is the horizontal displacement below the bedrock of the rear pile; is the infinitesimal length of the front pile and the back pile; is the mass per unit length of the rear pile; For time; is the bedrock foundation coefficient; is the cross-sectional width of the chair pile; is the input horizontal ground motion; is the length of the rear pile below the bedrock;

[0016] (2) Dynamic equilibrium differential equation below the front pile foundation rock:

[0017] (2)

[0018] Where: is the moment of inertia of the front pile; is the horizontal displacement of the front pile below the bedrock; is the mass per unit length of the front pile; is the length of the front pile below the bedrock;

[0019] (3) Dynamic equilibrium differential equation between the front pile foundation interface and the beam:

[0020] (3)

[0021] (4)

[0022] Where: is the horizontal displacement between the front pile foundation interface and the beam; is the foundation coefficient of the overburden soil; It is the length between the front pile foundation interface and the beam;

[0023] (4) Dynamic equilibrium differential equation between the rear pile foundation interface and the beam:

[0024] (5)

[0025] Where: is the horizontal displacement between the rear pile foundation interface and the beam;

[0026] (5) Dynamic equilibrium differential equation between the connection between the front pile and the beam and the anchor cable below:

[0027] (6)

[0028] (7)

[0029] Where: is the horizontal displacement between the connection between the front pile and the beam and the anchor cable below; It is the length between the connection between the front pile and the beam and the anchor cable below;

[0030] (6) The differential equation of dynamic balance between the anchor cable below the front pile and the anchor cable above it:

[0031] (8)

[0032] (9)

[0033] Where: is the horizontal displacement between the anchor cable below the front pile and the anchor cable above it; It is the length between the anchor cable below the front pile and the anchor cable above it;

[0034] (7) Dynamic equilibrium differential equation between the anchor cable above the front pile and the top of the overburden:

[0035] (10)

[0036] (11)

[0037] Where: is the horizontal displacement between the anchor cable above the front pile and the top of the overburden; It is the length from the anchor cable above the front pile to the top of the overburden;

[0038] (8) Dynamic equilibrium differential equation of the beam:

[0039] (12)

[0040] Where: is the moment of inertia of the beam; is the vertical displacement of the beam; is the infinitesimal length of the beam; is the mass per unit length of the beam; is the length of the beam.

[0041] Preferably, in step S2, the boundary conditions include:

[0042] (1) Boundary conditions at the bottom of the rear pile:

[0043] (13)

[0044] (14)

[0045] (2) Boundary conditions at the bottom of the front pile:

[0046] (15)

[0047] (16)

[0048] (3) Boundary conditions of the front pile at the base-cover interface:

[0049] (17)

[0050] Where: To find the order of derivative;

[0051] (4) Boundary conditions of the rear pile at the base-cover interface:

[0052] (18)

[0053] (5) The boundary conditions at the lower anchor cable are:

[0054] (19)

[0055] (20)

[0056] Where: is the angle between the lower anchor cable and the horizontal line; is the elastic modulus of the anchor cable;

[0057] (6) The boundary conditions at the upper anchor cable are:

[0058] (twenty one)

[0059] (twenty two)

[0060] Where: is the angle between the upper anchor cable and the horizontal line;

[0061] (7) Boundary conditions at the top of the front pile:

[0062] (23)

[0063] (24)

[0064] (8) Boundary conditions at the left end of the crossbeam and the front stake:

[0065] (25)

[0066] (26)

[0067] (27)

[0068] (28)

[0069] (29)

[0070] (9) Boundary conditions at the right end of the crossbeam and the rear stake:

[0071] (30)

[0072] (31)

[0073] (32)

[0074] (33)

[0075] (34).

[0076] As preferred, in step S3, the initial conditions comprise:

[0077] (35)

[0078] (36)

[0079] (37)

[0080] (38).

[0081] As preferred, in step S4, solving the dynamic equilibrium differential equation specifically comprises the following sub-steps:

[0082] S41: combining all the control differential equations at the nodes and the continuity conditions of each node into a matrix representation of a linear equation set by using difference operation, and obtaining the displacement vector of each node by matrix solution;

[0083] S42: Using interpolation and fitting methods to find the distribution continuous function of chair pile displacement;

[0084] S43: Calculate the axial force function of the anchor cable using the displacement coordination relationship between the anchor cable and the chair pile connection;

[0085] S44: taking a second derivative of the chair pile displacement distribution function with respect to time to obtain a distribution function of the acceleration of each part of the chair pile; taking a second derivative of the chair pile displacement distribution function with respect to its length direction to obtain a distribution function of the bending moment of each part of the chair pile.

[0086] The beneficial effects of the present invention are:

[0087] The present invention can more accurately calculate the deformation and stress of anchor chair piles under dynamic action by considering soil-structure interaction, and provide technical support for the design of anchor chair piles under seismic loads. BRIEF DESCRIPTION OF THE DRAWINGS

[0088] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0089] Figure 1 Schematic diagram of the flow of the dynamic calculation method of the anchor chair pile considering soil-structure interaction of the present invention;

[0090] Figure 2 This is a schematic diagram of slope reinforcement with anchor chair piles;

[0091] Figure 3 This is a schematic diagram of the calculation model for anchor chair piles;

[0092] Figure 4 A schematic diagram of a shaking table model test model and a layout of monitoring points for a slope reinforcement using anchor chair piles in a specific embodiment;

[0093] Figure 5 Dimensional drawing of an anchor chair pile model in a specific embodiment;

[0094] Figure 6 This is a diagram showing the arrangement of chair pile bending moment measurement points in a specific embodiment;

[0095] Figure 7 A waveform diagram of an input earthquake motion for a shaking table test in a specific embodiment;

[0096] Figure 8Schematic diagram of the comparison between the theoretical value and the experimental value of acceleration at the A1 measuring point in a specific embodiment;

[0097] Figure 9 Schematic diagram of the comparison between the theoretical displacement value and the experimental value of the D1 measuring point in a specific embodiment;

[0098] Figure 10 Schematic diagram of comparison between theoretical and experimental values ​​of the anchor cable axial force at F1 measuring point in a specific embodiment;

[0099] Figure 11 Schematic diagram of the comparison between the theoretical value and the experimental value of the anchor cable bending moment at the M7 measuring point in a specific embodiment. DETAILED DESCRIPTION

[0100] The present invention is further described below with reference to the accompanying drawings and examples. It should be noted that, in the absence of conflict, the embodiments in this application and the technical features in the embodiments can be combined with each other. It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meanings as those commonly understood by those of ordinary skill in the art to which this application belongs. The use of similar words such as "include" or "comprising" in the present invention means that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0101] like Figure 1 As shown, the present invention provides a dynamic calculation method for anchor chair piles considering soil-structure interaction, comprising the following steps:

[0102] S1: Based on the d'Alembert principle, a dynamic equilibrium differential equation is established that considers the interaction between the anchor cable, chair pile, and rock and soil. When establishing the dynamic equilibrium differential equation, the difference in the interaction between the chair pile and the front and rear soil is considered with the help of a symbolic function.

[0103] In a specific embodiment, when establishing the dynamic equilibrium differential equation, the anchor chair pile reinforced slope is as follows: Figure 2 The calculation model of anchor chair pile is shown as Figure 3 The dynamic equilibrium differential equation includes:

[0104] (1) Dynamic equilibrium differential equation below the pile foundation rock (BC section):

[0105] (1)

[0106] Where: is the elastic modulus of the chair pile; is the moment of inertia of the rear pile; is the horizontal displacement below the bedrock of the rear pile; is the infinitesimal length of the front pile and the back pile; is the mass per unit length of the rear pile; For time; is the bedrock foundation coefficient; is the cross-sectional width of the chair pile; is the input horizontal ground motion; is the length of the rear pile below the bedrock;

[0107] (2) Dynamic equilibrium differential equation below the front pile foundation rock (DE section):

[0108] (2)

[0109] Where: is the moment of inertia of the front pile; is the horizontal displacement below the bedrock of the front pile; is the mass per unit length of the front pile; is the length of the front pile below the bedrock;

[0110] (3) Dynamic equilibrium differential equation between the front pile foundation interface and the beam (EF segment):

[0111] (3)

[0112] (4)

[0113] Where: is the horizontal displacement between the front pile foundation interface and the beam; is the foundation coefficient of the overburden soil; It is the length between the front pile foundation interface and the beam;

[0114] (4) Dynamic equilibrium differential equation between the rear pile foundation interface and the beam (section AB):

[0115] (5)

[0116] Where: is the horizontal displacement between the rear pile foundation interface and the beam;

[0117] (5) Dynamic equilibrium differential equation between the connection point between the front pile and the crossbeam (point F) and the anchor cable below (point M) (FM segment):

[0118] (6)

[0119] (7)

[0120] Where: is the horizontal displacement between the connection between the front pile and the beam and the anchor cable below; It is the length between the connection between the front pile and the beam and the anchor cable below;

[0121] (6) Dynamic equilibrium differential equation between the anchor cable below the front pile (point M) and the anchor cable above (point N) (MN segment):

[0122] (8)

[0123] (9)

[0124] Where: is the horizontal displacement between the anchor cable below the front pile and the anchor cable above it; It is the length between the anchor cable below the front pile and the anchor cable above it;

[0125] (7) Dynamic equilibrium differential equation between the anchor cable above the front pile (point N) and the top of the overburden (point P) (NP segment):

[0126] (10)

[0127] (11)

[0128] Where: is the horizontal displacement between the anchor cable above the front pile and the top of the overburden; It is the length from the anchor cable above the front pile to the top of the overburden;

[0129] (8) Dynamic equilibrium differential equation of the beam (AF segment):

[0130] (12)

[0131] Where: is the moment of inertia of the beam; is the vertical displacement of the beam; is the infinitesimal length of the beam; is the mass per unit length of the beam; is the length of the beam.

[0132] S2: Continuously give the boundary conditions of the dynamic equilibrium differential equation based on force balance and deformation.

[0133] In a specific embodiment, the boundary conditions include:

[0134] (1) Boundary conditions at the rear pile bottom (point C):

[0135] (13)

[0136] (14)

[0137] That is, the relative displacement and rotation angle of the rear pile bottom (point C) are both 0;

[0138] (2) Boundary conditions at the bottom of the front pile (point D):

[0139] (15)

[0140] (16)

[0141] i.e. the relative displacement and rotation angle of the bottom of the front pile (point D) are both 0;

[0142] (3) Boundary conditions at the base-cover interface (point E) of the front pile:

[0143] (17)

[0144] wherein: is the derivative order;

[0145] i.e. the displacement, rotation angle, shear force, and bending moment of the front pile at the base-cover interface (point E) satisfy the continuity conditions;

[0146] (4) Boundary conditions at the base-cover interface (point B) of the back pile:

[0147] (18)

[0148] i.e. the displacement, rotation angle, shear force, and bending moment of the back pile at the base-cover interface (point B) satisfy the continuity conditions;

[0149] (5) Boundary conditions at the lower anchor (point M) are:

[0150] (19)

[0151] (20)

[0152] wherein: is the angle between the lower anchor and the horizontal line; is the elastic modulus of the anchor;

[0153] (6) Boundary conditions at the upper anchor (point N) are:

[0154] (21)

[0155] (22)

[0156] wherein: is the angle between the upper anchor and the horizontal line;

[0157] (7) Boundary conditions at the top of the front pile (point P) are:

[0158] (23)

[0159] (twenty four)

[0160] That is, the rotation angle and bending moment at point P are both zero;

[0161] (8) Boundary conditions at the connection between the left end of the beam and the front pile (point F):

[0162] (25)

[0163] That is, the vertical displacement at point F is zero;

[0164] (26)

[0165] That is, the sum of the bending moments at point F is 0;

[0166] (27)

[0167] That is, the horizontal displacements of the upper and lower parts of point F are equal;

[0168] (28)

[0169] That is, the deformation curvature (angle) of the upper and lower parts of point F is equal;

[0170] (29)

[0171] That is, the horizontal displacement of point F is equal to the horizontal displacement of point A;

[0172] (9) Boundary conditions at the connection between the right end of the beam and the rear pile (point A):

[0173] (30)

[0174] That is, the vertical displacement at point A is zero;

[0175] (31)

[0176] That is, the sum of the bending moments at point A is 0;

[0177] (32)

[0178] That is, the deformation curvature (angle) at point A is equal;

[0179] (33)

[0180] That is, the shear forces at points A and F of rod AF are equal;

[0181] (34).

[0182] That is, the shear forces at points A and B of rod AB are equal;

[0183] S3: The initial conditions of the dynamic equilibrium differential equation are given according to the displacement and velocity at the initial moment.

[0184] In a specific embodiment, the initial conditions include:

[0185] (35)

[0186] (36)

[0187] (37)

[0188] (38).

[0189] In the above embodiment, when When i=1, That is , represents the horizontal displacement below the rear pile bedrock, and the same applies to the others.

[0190] S4: Solve the dynamic equilibrium differential equation in combination with the boundary conditions and the initial conditions to obtain the distribution functions of acceleration, displacement and bending moment of each part of the anchor chair pile under earthquake action and the axial force function of the anchor cable.

[0191] In a specific embodiment, solving the dynamic equilibrium differential equation specifically includes the following sub-steps:

[0192] S41: Use differential operations to combine the control differential equations at all nodes and the continuity conditions of each node into a linear equation system represented by a matrix. By solving the matrix, the displacement vector of each node is obtained;

[0193] S42: Using interpolation and fitting methods to find the distribution continuous function of chair pile displacement;

[0194] S43: Calculate the axial force function of the anchor cable using the displacement coordination relationship between the anchor cable and the chair pile connection;

[0195] S44: taking a second derivative of the chair pile displacement distribution function with respect to time to obtain a distribution function of the acceleration of each part of the chair pile; taking a second derivative of the chair pile displacement distribution function with respect to its length direction to obtain a distribution function of the bending moment of each part of the chair pile.

[0196] In the present invention, the dynamic equilibrium differential equation is a coupled, nonlinear fourth-order differential equation, making it difficult to obtain a rigorous analytical solution. In the above embodiment, the seismic response of the anchor-chair pile is solved using the finite difference method. By using differential operations, the partial differential equation is transformed into a system of algebraic equations. This is equivalent to reducing the high-order partial differential equation to a system of linear equations that is amenable to matrix programming. This method achieves a high-precision numerical solution and high stability of the numerical results.

[0197] According to the standard finite difference principle, the chair pile structure is divided into N equal units along its length. The finite difference formats of the differential terms in the dynamic equilibrium differential equation are:

[0198] (39)

[0199] (40)

[0200] (41)

[0201] (42)

[0202] Where: is the displacement of each equally divided unit; 、 、 、 、 are the displacements of unit nodes i+1, i-1, i, i+2, and i-2 respectively; is the length of each equal unit;

[0203] The anchor chair pile is discretized into uniformly small lengths. Using differential operations, a finite difference format is developed for the equations of motion for each differential segment of the structure. The governing differential equations at all nodes and the continuity conditions for each node are combined into a system of linear equations represented by a matrix. Through matrix solution, the displacement vectors of each node are obtained. Interpolation and fitting methods are then used to determine the continuous distribution function U of the anchor chair pile displacement. The axial force function of the anchor cable is then determined using the displacement coordination relationship at the connection between the anchor cable and the chair pile. The quadratic derivative of the displacement distribution function with respect to time yields the distribution function of the acceleration at each part of the chair pile. The quadratic derivative of the displacement distribution function with respect to its length yields the distribution function of the bending moment at each part of the chair pile.

[0204] S5: Calculate the acceleration, displacement, bending moment and axial force at different times according to the function obtained in step S4.

[0205] In a specific embodiment, taking the anchor chair pile reinforcement slope in a certain place as an example, the anchor chair pile dynamic calculation method considering soil-structure interaction described in the present invention is used to calculate the deformation and force of the chair pile and obtain theoretical values, and a vibration table model test is carried out to obtain test values. The effectiveness of the present invention is proved by comparing the test values ​​and the theoretical values.

[0206] In this embodiment, the shaking table model test model and monitoring points are arranged as follows: Figure 4 The values ​​and units of the model parameters in the experiment are shown in Table 1:

[0207] Table 1 Model parameter values ​​and units in the experiment

[0208]

[0209] The test model size is 3.4m×1.5m×1.5m (length×width×height), and the anchor chair pile model size is as follows: Figure 5 As shown, the chair pile bending moment measurement points are arranged as follows Figure 6 shown.

[0210] The initial prestress of the anchor cable is set to 7.8N. In the shaking table test, the following is input: Figure 7 The results of the acceleration at A1, displacement at D1, anchor cable axial force at F1 and bending moment at M7 of the chair pile under the action of a sine wave with an amplitude of 0.05g and a frequency of 4Hz are shown in the figure. Figures 8-11 As shown. Figures 8-11 It can be seen that the theoretical value calculated by the present invention is relatively close to the experimental value result of the shaking table model test. The dynamic calculation method of the anchor chair pile considering the soil-structure interaction described in the present invention can accurately calculate the deformation and force of the anchor chair pile under dynamic action.

[0211] In summary, the present invention can more accurately calculate the deformation and stress of cable-anchored chair piles under dynamic action by considering soil-structure interaction. Compared with the prior art, the present invention is a significant improvement.

[0212] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with this profession can make some changes or modifications to equivalent embodiments of the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A dynamic calculation method for anchor chair piles considering soil-structure interaction, characterized in that: The following steps are involved: S1: Based on the d'Alembert principle, a dynamic equilibrium differential equation is established that considers the interaction between the anchor cable, chair pile, and rock and soil. When establishing the dynamic equilibrium differential equation, the difference in the interaction between the chair pile and the soil in front and behind is considered by using a symbolic function; The dynamic equilibrium differential equation includes: (1) Dynamic equilibrium differential equation below the pile foundation rock: （1） Where: is the elastic modulus of the chair pile; is the moment of inertia of the rear pile; is the horizontal displacement below the bedrock of the rear pile; is the infinitesimal length of the front pile and the back pile; is the mass per unit length of the rear pile; For time; is the bedrock foundation coefficient; is the cross-sectional width of the chair pile; is the input horizontal ground motion; is the length of the rear pile below the bedrock; (2) Dynamic equilibrium differential equation below the front pile foundation rock: （2） Where: is the moment of inertia of the front pile; is the horizontal displacement below the bedrock of the front pile; is the mass per unit length of the front pile; is the length of the front pile below the bedrock; (3) Dynamic equilibrium differential equation between the front pile foundation interface and the beam: （3） （4） Where: is the horizontal displacement between the front pile foundation interface and the beam; is the foundation coefficient of the overburden soil; It is the length between the front pile foundation interface and the beam; (4) Dynamic equilibrium differential equation between the rear pile foundation interface and the beam: （5） Where: is the horizontal displacement between the rear pile foundation interface and the beam; (5) Dynamic equilibrium differential equation between the connection between the front pile and the beam and the anchor cable below: （6） （7） Where: is the horizontal displacement between the connection between the front pile and the beam and the anchor cable below; It is the length between the connection between the front pile and the beam and the anchor cable below; (6) The differential equation of dynamic balance between the anchor cable below the front pile and the anchor cable above it: （8） （9） Where: is the horizontal displacement between the anchor cable below the front pile and the anchor cable above it; It is the length between the anchor cable below the front pile and the anchor cable above it; (7) Dynamic equilibrium differential equation between the anchor cable above the front pile and the top of the overburden: （10） （11） Where: is the horizontal displacement between the anchor cable above the front pile and the top of the overburden; It is the length from the anchor cable above the front pile to the top of the overburden; (8) Dynamic equilibrium differential equation of the beam: （12） Where: is the moment of inertia of the beam; is the vertical displacement of the beam; is the infinitesimal length of the beam; is the mass per unit length of the beam; is the length of the beam; S2: Continuously give the boundary conditions of the dynamic equilibrium differential equation based on force balance and deformation; S3: giving the initial conditions of the dynamic equilibrium differential equation according to the initial displacement and the initial velocity; S4: solving the dynamic equilibrium differential equation in combination with the boundary conditions and the initial conditions to obtain the distribution functions of acceleration, displacement, and bending moment of each part of the anchor chair pile under earthquake action and the axial force function of the anchor cable; S5: Calculate the acceleration, displacement, bending moment and axial force at different times according to the function obtained in step S4.

2. The dynamic calculation method of anchor chair pile considering soil-structure interaction according to claim 1 is characterized in that: In step S2, the boundary conditions include: (1) Boundary conditions at the bottom of the rear pile: （13） （14） (2) Boundary conditions at the bottom of the front pile: （15） （16） (3) Boundary conditions of the front pile at the base-cover interface: （17） Where: To find the order of derivative; (4) Boundary conditions of the rear pile at the base-cover interface: （18） (5) The boundary conditions at the lower anchor cable are: （19） （20） Where: is the angle between the lower anchor cable and the horizontal line; is the elastic modulus of the anchor cable; (6) The boundary conditions at the upper anchor cable are: （21） （22） Where: is the angle between the upper anchor cable and the horizontal line; (7) Boundary conditions at the top of the front pile: （23） （24） (8) Boundary conditions at the connection between the left end of the beam and the front pile: （25） （26） （27） （28） （29） (9) Boundary conditions at the connection between the right end of the beam and the rear pile: （30） （31） （32） （33） （34）。 3. The dynamic calculation method of anchor chair pile considering soil-structure interaction according to claim 2 is characterized in that: In step S3, the initial conditions include: （35） （36） （37） （38）。 4. The dynamic calculation method of anchor chair pile considering soil-structure interaction according to any one of claims 1 to 3, characterized in that: In step S4, solving the dynamic equilibrium differential equation specifically includes the following sub-steps: S41: Use differential operations to combine the control differential equations at all nodes and the continuity conditions of each node into a linear equation system represented by a matrix. By solving the matrix, the displacement vector of each node is obtained; S42: Using interpolation and fitting methods to find the distribution continuous function of chair pile displacement; S43: Calculate the axial force function of the anchor cable using the displacement coordination relationship between the anchor cable and the chair pile connection; S44: taking a second derivative of the chair pile displacement distribution function with respect to time to obtain a distribution function of the acceleration of each part of the chair pile; taking a second derivative of the chair pile displacement distribution function with respect to its length direction to obtain a distribution function of the bending moment of each part of the chair pile.

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