Method for obtaining variation law of pile-rock interface deformation and strength parameters along pile depth

Abstract

The present invention discloses a method for obtaining the variation pattern of pile-rock interface deformation and strength parameters along the depth of the pile, comprising: 1. obtaining rock samples and pile-rock interface specimens on site, and conducting pile-rock interface shear and uniaxial tests; 2. obtaining the strength and deformation parameter ranges and the maximum failure shear strain ε of the pile-rock interface; 3. performing uniform design based on the pile-rock interface parameter ranges to obtain the pile-rock interface parameters required for numerical simulation; 4. establishing a numerical model for the pile-rock interface shear test and performing calculations to obtain the pile-rock interface shear strain ε′; and 5. performing parameter inversion. The present invention can combine a limited number of tests with numerical simulations, and ultimately determine the variation pattern of the pile-rock interface strength and deformation parameters along the depth of the pile through parameter inversion, significantly shortening the test cycle and avoiding the situation where some data cannot be obtained due to insufficient specimens.

Description

Technical Field

[0001] The present invention relates to the field of rock mechanics testing, and in particular to an intelligent method for obtaining the variation law of pile-rock interface deformation and strength parameters along the pile depth based on shear tests and numerical simulation methods. Background Art

[0002] Pile foundations are widely used in geotechnical engineering, and the mechanical properties of the pile-rock interface have a significant impact on the bearing capacity of pile foundations. The pile-rock interface is composed of two different materials, which can exhibit inconsistent deformation. This can easily generate large shear stresses at the interface, and the mechanical properties of the interface are closely related to the properties of the rock mass. However, obtaining pile-rock interface specimens during experimental research is often difficult, and laboratory preparation is relatively cumbersome and time-consuming. Therefore, it is essential to study how the deformation and strength parameters of the pile-rock interface vary along the depth of the pile.

[0003] Traditional research methods are mostly based on experiments, which are time-consuming and labor-intensive to implement. The preparation of samples does not conform to the actual formation law of the pile-rock interface. In addition, the traditional simulated shear test method does not take into account the influence of rock surface roughness on the calculation results, and the results are not accurate enough. Summary of the Invention

[0004] The present invention aims to address the deficiencies of the above-mentioned prior art and proposes a method for obtaining the variation law of pile-rock interface deformation and strength parameters along the pile depth, so as to combine a limited number of tests with numerical simulations, and determine the variation law of pile-rock interface strength and deformation parameters along the pile depth by parameter inversion, thereby shortening the test cycle and avoiding the situation where some data cannot be obtained due to insufficient samples.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] The method for obtaining the variation law of pile-rock interface deformation and strength parameters along the pile depth of the present invention is characterized in that it comprises the following steps:

[0007] S1. Obtain rock samples on site and prepare pile-rock interface specimens;

[0008] S2. Calculate the lateral pressure at the pile-rock interface of the pile-rock interface specimen at the current pile depth h, and use it as the axial pressure applied during the shear test;

[0009] S3, using the axial pressure to perform a pile-rock interface shear test on the pile-rock interface sample, and at the same time, performing a uniaxial test on the pile-rock interface sample, thereby obtaining the pile-rock interface parameters and the maximum failure shear strain ε at the current pile depth position h, and determining the range of the interface parameters according to the interface parameters; the interface parameters include: strength parameters and deformation parameters, the strength parameters include: interface cohesion c, interface internal friction angle The deformation parameters include: normal stiffness k n , tangential stiffness k s ;

[0010] S4, uniformly design the range of the interface parameters of the pile-rock interface at the current pile depth position h, and obtain n groups of pile-rock interface parameters at the current pile depth position h, recorded as Among them, k sm 、c m 、 k nm represents the pile-rock interface parameters of the mth group, k sm 、c m 、 k nm They represent the mth tangential stiffness, the mth interfacial cohesion, the mth interfacial internal friction angle, and the mth normal stiffness respectively;

[0011] S5. Establish a numerical model for the pile-rock interface shear test, and substitute n groups of pile-rock interface parameters at the current pile depth h into the numerical model for simulation calculation, thereby obtaining n pile-rock interface shear strains {ε1′, …, ε m ′,……,ε n ′}; where ε m ′ represents the mth pile-rock interface shear strain at the current pile depth h;

[0012] S6, calculate the n pile-rock interface shear strains {ε1′, …, ε m ′,……,ε n ′} are compared with the maximum failure shear strain ε obtained from the test, and the pile-rock interface shear strain ε closest to ε is selected * The corresponding pile-rock interface parameter k s * 、c * 、 k n * as the optimal pile-rock interface parameters;

[0013] S7, according to the process of steps S2-S6, obtain interface parameters and maximum failure shear strain under different pile depth positions, and use the optimal pile-rock interface parameters under different pile depth positions as training samples for parameter inversion, and use neural network genetic algorithm to carry out learning training and parameter inversion to the training samples, obtain the relationship between pile-rock interface parameters and maximum failure shear strain under different pile depth positions;

[0014] S8. Use a neural network genetic algorithm to perform learning and parameter inversion on the maximum shear strain corresponding to different pile depths to obtain the relationship between different pile depths and the maximum failure shear strain;

[0015] S9. Based on the two relationships of S7 and S8, a mathematical model of the variation law of pile-rock interface parameters along the pile depth is established to output the interface parameters at any depth.

[0016] The present invention provides an electronic device, comprising a memory and a processor, wherein the memory is used to store a program that supports the processor to execute the acquisition method, and the processor is configured to execute the program stored in the memory.

[0017] The present invention provides a computer-readable storage medium having a computer program stored thereon. The computer-readable storage medium is characterized in that the computer program executes the steps of the acquisition method when executed by a processor.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The method of the present invention combines a limited number of tests with numerical simulations, and determines the variation patterns of the pile-rock interface strength and deformation parameters along the pile depth position through parameter inversion, thereby greatly shortening the test cycle and avoiding the situation where some data cannot be obtained due to insufficient samples. In addition, when using the numerical simulation method to simulate the pile-rock interface shear test modeling, the present invention substitutes the original morphological data of the rock sample into it through 3D scanning technology, so that the numerical model is more consistent with the actual situation and the calculation results are more accurate. The simulation results are verified by using parameter inversion, so that the obtained results are more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Flowchart for the implementation of the present invention. DETAILED DESCRIPTION

[0021] In this embodiment, Figure 1 As shown, a method for obtaining the variation law of pile-rock interface deformation and strength parameters along the pile depth position includes the following steps:

[0022] S1. Obtain rock samples on site and prepare pile-rock interface specimens:

[0023] Obtain rock samples on site, cut them into required sizes and dimensions, perform 3D scanning on the test rock samples, and then prepare the test specimens. When preparing the samples, first put the cut rock samples into the mold, then put the prepared concrete into it, vibrate it, pressurize it, and then cure it;

[0024] S2. Calculate the lateral pressure at the pile-rock interface of the pile-rock interface specimen at the current pile depth h, and use it as the axial pressure applied during the shear test;

[0025] The axial pressure applied during the test is equal to the lateral pressure at the corresponding pile depth;

[0026] S3. Conducting a pile-rock interface shear test and a uniaxial test on the pile-rock interface specimen using axial pressure, and obtaining the pile-rock interface parameters and the maximum failure shear strain ε at the current pile depth h, thereby determining the range of the interface parameters based on the interface parameters; the interface parameters include strength parameters and deformation parameters, the strength parameters include interface cohesion c and interface internal friction angle φ; the deformation parameters include normal stiffness kn and tangential stiffness ks;

[0027] Using the lateral pressure calculated by S2 as the axial pressure applied in the test, shear and uniaxial tests on the pile-rock interface were carried out to obtain the parameter ranges of strength (interface cohesion c, interface internal friction angle φ) and deformation (normal stiffness kn, tangential stiffness ks) of the pile-rock interface and the maximum failure shear strain ε.

[0028] S4, uniformly design the range of the interface parameters of the pile-rock interface at the current pile depth position h, and obtain n groups of pile-rock interface parameters at the current pile depth position h, denoted as {k s1 , c1, φ1, k n1 ,……,k sm 、c m 、φ m 、k nm ,……,k sn 、c n 、φ n 、k nn}; where k sm 、 cm 、φ m 、k nm represents the pile-rock interface parameters of the mth group, k sm 、c m 、φ m 、k nm They represent the mth tangential stiffness, the mth interfacial cohesion, the mth interfacial internal friction angle, and the mth normal stiffness respectively;

[0029] The range of parameters is obtained from experiments, and the limited experimental data is expanded through uniform design, making the simulation range more comprehensive and the results more accurate;

[0030] S5. Establish a numerical model for the pile-rock interface shear test, and substitute n groups of pile-rock interface parameters at the current pile depth h into the numerical model for simulation calculation, so as to obtain n pile-rock interface shear strains {ε1′, …, ε m ′,……,ε n ′}; where ε m ′ represents the mth pile-rock interface shear strain at the current pile depth h;

[0031] After the rock sample is cut into the required shape and size, the surface morphology of the rock sample is obtained by 3D scanning technology. Then, the rock sample is reconstructed in three dimensions using CAD and GeoStudio software. A numerical model of the pile-rock interface shear test is established. The above n groups of parameters are substituted into the model for simulation calculation to obtain the pile-rock interface shear strains ε1′, …, ε n ';

[0032] S6, calculate the n pile-rock interface shear strains {ε1′, …, ε m ′,……,ε n ′} are compared with the maximum failure shear strain ε obtained from the test, and the pile-rock interface parameter k corresponding to the pile-rock interface shear strain ε* closest to ε is selected. s *, c*, φ*, k n *;

[0033] Compare the shear strain ε′ obtained by simulation with the shear strain ε obtained by experiment. The simulation parameter k corresponding to the close output strain is s *, c*, φ*, k n *;

[0034] S7, according to the process of steps S2-S6, obtain the interface parameters and maximum failure shear strain at different pile depths, and convert {k s *, c*, φ*, k n *, ε*} as the training samples for parameter inversion, and use the neural network genetic algorithm to perform learning training and parameter inversion on the training samples to obtain the relationship between the pile-rock interface parameters and the maximum failure shear strain at different pile depths h; S8, the test data used are used for parameter inversion through the neural network genetic algorithm to obtain k s *, c*, φ*, k n *Relationship with ε*;

[0035] S8. The maximum shear strain ε at different pile depths is trained and parameter inverted by a neural network genetic algorithm to obtain the relationship between the different pile depths h and the maximum failure shear strain ε;

[0036] S9. Thus, a mathematical model of the variation law of pile-rock interface parameters along the pile depth is obtained, which is used to output the interface parameters at any depth.

[0037] Finite number tests were combined with simulations and a neural network genetic algorithm was used to establish the relationship between pile-rock interface parameters and pile depth.

Claims

1. A method for obtaining the variation law of pile-rock interface deformation and strength parameters along the pile depth, characterized in that: The following steps are involved: S1. Obtain rock samples on site and prepare pile-rock interface specimens; S2. Calculate the lateral pressure at the pile-rock interface of the pile-rock interface specimen at the current pile depth h, and use it as the axial pressure applied during the shear test; S3, using the axial pressure to perform a pile-rock interface shear test on the pile-rock interface sample, and at the same time, performing a uniaxial test on the pile-rock interface sample, thereby obtaining the pile-rock interface parameters and the maximum failure shear strain ε at the current pile depth position h, and determining the range of the interface parameters according to the interface parameters; The interface parameters include: strength parameters and deformation parameters, the strength parameters include: interface cohesion c, interface internal friction angle The deformation parameters include: normal stiffness k n , tangential stiffness k s ; S4, uniformly design the range of the interface parameters of the pile-rock interface at the current pile depth position h, and obtain n groups of pile-rock interface parameters at the current pile depth position h, denoted as {k s1 、c1、 k n1 ,……,k sm 、c m 、 k nm ,……,k sn 、c n 、 k nn }; where k sm 、c m 、 k nm represents the pile-rock interface parameters of the mth group, k sm 、c m 、 k nm They represent the mth tangential stiffness, the mth interfacial cohesion, the mth interfacial internal friction angle, and the mth normal stiffness respectively; S5. Establish a numerical model for the pile-rock interface shear test, and substitute n groups of pile-rock interface parameters at the current pile depth h into the numerical model for simulation calculation, thereby obtaining n pile-rock interface shear strains {ε1′, …, ε m ′,……,ε n ′}; where ε m ′ represents the mth pile-rock interface shear strain at the current pile depth h; S6, calculate the n pile-rock interface shear strains {ε1′, …, ε m ′,……,ε n ′} are compared with the maximum failure shear strain ε obtained from the test, and the pile-rock interface shear strain ε closest to ε is selected * The corresponding pile-rock interface parameter k s * 、c * 、 k n * as the optimal pile-rock interface parameters; S7, according to the process of steps S2-S6, obtain interface parameters and maximum failure shear strain under different pile depth positions, and use the optimal pile-rock interface parameters under different pile depth positions as training samples for parameter inversion, and use neural network genetic algorithm to carry out learning training and parameter inversion to the training samples, obtain the relationship between pile-rock interface parameters and maximum failure shear strain under different pile depth positions; S8. Use a neural network genetic algorithm to perform learning and parameter inversion on the maximum shear strain corresponding to different pile depths to obtain the relationship between different pile depths and the maximum failure shear strain; S9. Based on the two relationships of S7 and S8, a mathematical model of the variation law of pile-rock interface parameters along the pile depth is established to output the interface parameters at any depth.

2. An electronic device comprising a memory and a processor, characterized in that: The memory is used to store a program for supporting a processor to execute the method according to claim 1 , and the processor is configured to execute the program stored in the memory.

3. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to claim 1 are performed.

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