Novel method for constructing soil constitutive model based on stress heuristic test

Abstract

The invention relates to a novel method for constructing a soil constitutive model based on a stress test, which comprises the following steps of: performing the stress test on a soil sample by adopting a discrete element method, and analyzing the strain response of the soil under the action of stress increment in different directions; deriving key composition elements of the constitutive model based on the response envelope obtained by the stress test, including a yield surface, a plastic flow direction, a shear expansion coefficient and a plastic modulus; establishing a state-related constitutive model in combination with a critical state theory; and verifying the prediction capability of the constitutive model through a DEM heuristic test and a triaxial loading test. The method has the beneficial effects that the incremental behaviors of the soil body under different stress paths can be accurately captured through a stress tentative test, and the simulation precision of the model is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the field of geotechnical engineering technology, and more specifically, to a new method for constructing a soil constitutive model based on a stress trial test. Background Art

[0002] The mechanical behavior of soil has complex characteristics such as nonlinearity, irreversibility, and state dependence. Traditional soil constitutive models are usually established based on the phenomenological relationship of the total stress-strain relationship, which makes it difficult to accurately describe the incremental response of soil. The discrete element method (DEM), as a numerical simulation method, can perform multiple stress test trials on the same specimen and measure elastic and plastic strains separately, providing a new approach to the establishment of soil constitutive models. However, existing technologies have not fully utilized stress test techniques to construct specific constitutive models, and lack systematic model verification methods. Summary of the Invention

[0003] The purpose of the present invention is to address the deficiencies of the existing technology and propose a new method for constructing a soil constitutive model based on stress trial tests.

[0004] First, a new method for constructing a soil constitutive model based on stress exploratory tests is provided, including:

[0005] Step 1: Use the discrete element method to conduct stress test on soil samples and analyze the strain response of soil under stress increments in different directions;

[0006] Step 2: Based on the response envelope obtained from the stress test, the key components of the constitutive model are derived, including the yield surface, plastic flow direction, shear dilatancy coefficient, and plastic modulus;

[0007] Step 3: Combine the critical state theory to establish a state-dependent constitutive model;

[0008] Step 4: Verify the predictive ability of the constitutive model through DEM trial tests and triaxial loading tests.

[0009] Preferably, step 1 comprises:

[0010] Step 1.1, sample preparation: Discrete element method simulation was performed to prepare samples with different porosity ratios by adjusting the inter-particle friction coefficient μ, and the samples were consolidated to different stress states;

[0011] Step 1.2: Apply a series of stress increments dσ of the same magnitude but different directions to the specimen. r , measure the corresponding strain increment dε r ;

[0012] Step 1.3, strain decomposition: Use the parallel trial method to measure the total strain increment and elastic strain increment respectively, and calculate the plastic strain increment by the difference.

[0013] Preferably, in step 1.2, two types of analysis are used: an axisymmetric stress test and a deviatoric stress test; for the axisymmetric test, the two normal stress components in the horizontal direction have the same magnitude; in the deviatoric stress test, the stress increment is applied on the deviatoric stress plane.

[0014] Preferably, step 2 comprises:

[0015] Step 2.1: Express the plastic strain increment as:

[0016]

[0017] Where, is the loading factor, which represents the plastic deviatoric strain increment The size of χ ij is the direction of plastic flow, and the deviatoric strain part n ij and volume part Composition; n ij is the deviatoric strain unit tensor, specified by direction; is the shear dilatancy coefficient;

[0018] Step 2.2: According to the formula in step 2.1, deduce the partial plastic flow direction n ij and dilatancy coefficient D;

[0019] Step 2.3: Express the plastic modulus as:

[0020]

[0021] Where f is the yield surface, Specified σ ij The direction of the external normal of f, H is a function of the internal state variables related to the hardening rule, K p is the plastic modulus.

[0022] Preferably, step 3 includes:

[0023] Step 3.1. Determine the critical state. The critical state refers to the state in which the soil continues to shear and deform while its stress and volume remain unchanged.

[0024] Step 3.2: Derive the linear constitutive relation, yield surface, hardening law, plastic flow direction, plastic modulus, and dilatancy coefficient; and calculate the total strain increment.

[0025] Step 3.3: Combine the elastic relationship, yield surface, plastic flow direction, hardening rule and plastic modulus to construct a soil constitutive model with soil state correlation.

[0026] In a second aspect, a new system for constructing a soil constitutive model based on a stress test is provided, which is used to execute any of the methods described in the first aspect, including:

[0027] The analysis module is used to conduct stress test on soil samples using discrete element method and analyze the strain response of soil under stress increments in different directions;

[0028] A derivation module is used to derive key components of the constitutive model, including the yield surface, plastic flow direction, shear dilatancy coefficient, and plastic modulus, based on the response envelope obtained from the stress probe test;

[0029] Establish a module for combining critical state theory to establish state-dependent constitutive models;

[0030] The verification module is used to verify the prediction ability of the constitutive model through DEM trial test and triaxial loading test.

[0031] According to a third aspect, a computer storage medium is provided, wherein a computer program is stored in the computer storage medium; when the computer program is executed on a computer, the computer executes any one of the methods described in the first aspect.

[0032] In a fourth aspect, an electronic device is provided, including:

[0033] Memory, used to store computer programs;

[0034] A processor is used to execute the computer program to implement any method as described in the first aspect.

[0035] The beneficial effects of the present invention are:

[0036] 1. Improved simulation accuracy: Traditional constitutive models are typically based on the total stress-strain relationship and are difficult to accurately describe the incremental response of soil. This invention, through stress probing tests, can accurately capture the incremental behavior of soil under different stress paths, significantly improving the simulation accuracy of the model.

[0037] 2. Comprehensive consideration of state correlation: The present invention fully considers the state correlation of soil (such as density, confining pressure and stress ratio). By constructing a state-dependent constitutive model, it can more accurately simulate the mechanical behavior of soil under different initial states.

[0038] 3. Reduce experimental costs and time: The present invention uses discrete element method (DEM) to perform stress detection tests, which can quickly generate large amounts of data in a virtual environment and reduce dependence on expensive and time-consuming laboratory tests.

[0039] 4. Improve the safety and cost-effectiveness of engineering designs: This invention accurately predicts the stress-strain relationship and volumetric response of soil under different loading conditions, providing a reliable theoretical basis for engineering design and helping to improve the safety and cost-effectiveness of projects. Simulating soil behavior under different initial states and loading conditions also provides optimization recommendations for engineering designs, such as optimizing soil density and confining pressure to maximize the mechanical properties of the soil. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 The response envelope diagram based on the stress test provided by the present invention;

[0041] Figure 2 Schematic diagram of the normal direction of the plastic potential surface provided by the present invention; (a) the normal direction of the yield surface and the plastic potential surface on the Rendulic plane and (b) the deviatoric plane;

[0042] Figure 3 A comparison chart of typical stress test results and model prediction results provided by the present invention;

[0043] Figure 4 A comparison chart of drained triaxial compression test results and model prediction results at different initial porosity ratios and confining pressures of p0 = 200 kPa and 500 kPa provided by the present invention;

[0044] Figure 5 A comparison chart of the undrained triaxial compression test results and the model prediction results under different densities and confining pressures provided by the present invention;

[0045] Figure 6 This is a comparison chart of the DEM multi-axial stress spatial test results and the model prediction results provided by the present invention. DETAILED DESCRIPTION

[0046] The present invention will be further described below with reference to the following examples. The following examples are provided only to facilitate understanding of the present invention. It should be noted that, without departing from the principles of the present invention, it is possible for a person skilled in the art to make various modifications to the present invention, and such improvements and modifications fall within the scope of the claims of the present invention.

[0047] Example 1:

[0048] Example 1 of the present application provides a new method for constructing a soil constitutive model based on a stress test, comprising:

[0049] Step 1: Use the discrete element method (DEM) to conduct stress test on soil samples and analyze the strain response of soil under stress increments in different directions.

[0050] Step 1 includes:

[0051] Step 1.1, Sample preparation: using PFC 3D Discrete element method simulations were performed. By adjusting the inter-particle friction coefficient μ, specimens with different porosity ratios were prepared and consolidated to different stress states, including different confining pressures p, stress ratios η = q / p, and intermediate principal stress coefficients b = (σ2-σ3) / (σ1-σ3) (p and q represent the mean stress and shear stress, respectively; σ1, σ2, and σ3 represent the major principal stress, intermediate principal stress, and minor principal stress, respectively).

[0052] Step 1.2: Apply a series of stress increments dσ of the same magnitude but different directions to the specimen. r , measure the corresponding strain increment dε r .

[0053] In step 1.2, two types of analysis are used: axisymmetric test and deviatoric stress test. For the axisymmetric test, the two normal stress components in the horizontal direction have the same magnitude;

[0054] (dσ 22 =dσ 33 ), expressed as:

[0055] dσ 11 =dσ r cos(α dσ )(1a)

[0056]

[0057] in, Indicates the magnitude of the stress increment; dσ 11 , dσ 22 , dσ 33 are the normal stress increments in the x1, x2, and x3 directions respectively; the stress probe direction is the angle α between the stress increment vector and the horizontal direction. dσ express.

[0058] In the case of a deviatoric stress test, the stress increment is applied on the deviatoric stress plane (dσ 11 +dσ 22 +dσ 33 =0), expressed as:

[0059]

[0060] In the formula, the stress test direction passes through the angle θ dσ express.

[0061] Step 1.3, strain decomposition: Use the parallel trial method to measure the total strain increment and elastic strain increment respectively, and calculate the plastic strain increment by the difference

[0062] Step 2: Based on the strain response envelope obtained from the stress probe test, the key components of the constitutive model are derived, including the yield surface, plastic flow direction, shear dilatancy coefficient, and plastic modulus.

[0063] Step 2 includes:

[0064]

[0065] Where, is the loading factor, which represents the plastic deviatoric strain increment The size of χ ij is the direction of plastic flow, and the deviatoric strain part n ij and volume part Composition; n ij is the plastic deviatoric strain unit tensor, specified by direction; is the shear dilatancy coefficient; δ ij is the Kronecker symbol, when i=j, δ ij =1, i≠j when δ ij =0.

[0066] Step 2.2: Based on the formula in step 2.1, derive the deviatoric stress flow direction n ij and shear dilation coefficient D.

[0067] like Figure 1 As shown in the figure, the direction of the plastic strain increment hardly changes with the direction of the stress increment. Therefore, the direction of the plastic strain increment with the largest amplitude can be taken as the direction of plastic flow, that is, the direction corresponding to the vector OA in the figure, and Therefore, the plastic partial stress unit tensor n ij And the shear dilation coefficient D can be calculated by the following formula:

[0068]

[0069] in, express The bias part, for The second-order norm of and for The corresponding amplitudes of the plastic volume strain increment and the plastic deviatoric strain increment.

[0070] Step 2.3: Express the plastic modulus as:

[0071]

[0072] Where f is the yield surface, Specified σ ij The direction of the external normal of f, H is a function of the internal state variables related to the hardening rule, K p is the plastic modulus. According to formula (5), for a given initial state (i.e. K p When the stress probe is perpendicular to the yield surface, the amplitude of L reaches its maximum value, because at this time dσ ij and Same direction, dσ ij reaches its maximum value. Therefore, if Figure 2 As shown in (a), the yield surface at point O can be defined as perpendicular to the vector OA', that is, perpendicular to the stress probe direction corresponding to the maximum plastic deviatoric strain increment, that is:

[0073]

[0074] Among them, dσ OA' Represents the stress increment specified by the vector OA'. After determining the normal direction of the yield surface, the plastic modulus K can be calculated according to formula (5): p :

[0075]

[0076] According to formula (6), and Same direction, so

[0077] Through the above process, the normal direction of the yield surface, plastic modulus and plastic flow direction can be obtained for a given specimen based on its response envelope.

[0078] Step 3: Combine the critical state theory to establish a state-dependent constitutive model.

[0079] Step 4: Verify the predictive ability of the constitutive model through DEM trial tests and triaxial loading tests.

[0080] Example 2:

[0081] Based on Example 1, Example 2 of the present application provides specific steps for constructing a soil constitutive model based on a stress trial test, including:

[0082] Step 1: Use the discrete element method to conduct stress test on soil samples and analyze the strain response of soil under stress increments in different directions.

[0083] Step 2: Based on the response envelope obtained from the stress probe test, the key components of the constitutive model are derived, including the yield surface, plastic flow direction, shear dilatancy coefficient and plastic modulus.

[0084] Step 3: Combine the critical state theory to establish a state-dependent constitutive model.

[0085] Step 3 includes:

[0086] Step 3.1: Determine the critical state.

[0087] The critical state refers to the state in which the soil continues to shear deform while its stress and volume remain unchanged.

[0088] The critical state parameter ψ is expressed as: ψ=ee c , where e c is the critical porosity ratio, e c The relationship between and the confining pressure p is expressed by the following equation:

[0089] e c =e Γ -λ c (p / p a ) ξ (8)

[0090] This relationship shows that as the confining pressure p increases, the critical porosity e c Gradually decrease.

[0091] The critical stress ratio M is expressed as follows:

[0092] M=M c g(θ σ )(9a)

[0093] Among them, g(θ σ ) changes smoothly with the stress Lode angle, from triaxial compression (θ σ =-30 ο ) to the unit value of triaxial stretching (θ σ =30°) e / M c , where M e and M c are the critical stress ratios in triaxial tension and compression, respectively, and the function g(θ σ ) is expressed as:

[0094]

[0095] Step 3.2: Using the aforementioned method for constructing a constitutive model based on stress test, taking a relatively simple isotropic sand sample as an example, derive specific expressions for its elastic constitutive relation, yield surface, hardening law, plastic flow direction, plastic modulus, and shear dilatancy coefficient, and calculate the total strain increment.

[0096] Specifically, step 3.2 includes:

[0097] (1) Derivation of elastic constitutive relations

[0098] Calculation of elastic strain increment: Based on the elastic relationship, the calculation formula for elastic strain increment is:

[0099]

[0100] According to formula (10), the elastic stress expression is:

[0101]

[0102] Where: G0 is the material constant, ν is Poisson's ratio, p a =101kPa represents atmospheric pressure.

[0103] (2) Yield surface derivation

[0104] The normal direction of the yield surface is determined according to the maximum value of the plastic strain increment. The yield surface is perpendicular to the corresponding stress test direction in the stress space. Figure 2 The test results in (a) show that the normal of the yield surface is roughly perpendicular to the line connecting the current stress and the origin, so the yield surface expression in triaxial space is:

[0105] f=η-H=0 (12)

[0106] and Figure 2 The experimental results in (b) show that the shape of the yield surface on the deviatoric plane is related to the Lode angle and is not circular. Therefore, the yield surface expression in tensor space is:

[0107] f=η / g(θ' σ )-H=0 (13a)

[0108] Where η is the stress ratio, g(θ' σ ) is the interpolation function related to the Lode angle, and H is the hardening parameter.

[0109]

[0110] Here, c' is a model parameter and can take different values from c in formula (9b). Therefore, the shapes of the critical stress surface and the yield surface can be adjusted independently by the parameters c and c', respectively.

[0111] (3) Derivation of the hardening law

[0112] The hardening law can be obtained by finding the consistency equation of the yield surface in equation (13):

[0113] pm ij dr ij -K p L=0

[0114] (14) where m ij is the outer normal direction of the yield surface in Eq. (13a) on the deviatoric plane, which can be expressed as:

[0115]

[0116] (4) Derivation of plastic modulus

[0117] Calculate the plastic modulus through the consistency condition, plastic modulus K p The expression can be simplified to:

[0118]

[0119] Where dη is the increment of stress ratio.

[0120] Since the stress state of the soil remains unchanged in the critical state, the plastic modulus K at this time is p (η=M,ψ=0)=0. Therefore, K p The general form of is:

[0121] K p =f(η,e,p)[M c g(θ σ )e -nψ -η] (17)

[0122] Among them, f(η,e,p) is a function of stress ratio, porosity ratio and confining pressure, reflecting K p State correlation of ψ=ee c It is a state parameter used to describe the state of soil under the combined influence of density and stress level.

[0123] Assuming that the effects of η, e, and p are uncoupled, then:

[0124] f(η,e,p)=f1(η)f2(e)f3(p) (18)

[0125] Where f1, f2, and f3 are functions of stress ratio, porosity ratio, and effective mean stress, respectively.

[0126] K in formula (17) p The following two boundary conditions should be met:

[0127] Condition 1: At the initial loading moment, the soil behaves in a purely elastic manner, K p (η=0)=∞;

[0128] Condition 2: The value of the plastic modulus is negatively correlated with the stress ratio.

[0129] According to conditions 1 and 2, f1 can be expressed as:

[0130]

[0131] Where α is the model parameter.

[0132] In addition, the stress test results under different confining pressures and porosity ratios show that the value of the soil plastic modulus is positively correlated with the confining pressure and negatively correlated with the porosity ratio. Therefore, the expressions for f2 and f3 can be obtained as follows:

[0133] f2(e)=h1exp(-h2e); f3=(p / p a ) β (20)

[0134] Where h1, h2 and β are model parameters.

[0135] The plastic modulus expression obtained by combining equations (17) to (20) is:

[0136]

[0137] (5) Derivation of plastic flow direction

[0138] The direction of plastic flow determines the direction of plastic strain increment. Figure 2 As shown in Figure 2, the stress test results show that the soil follows the non-associated flow law on the Rendulic plane and the associated flow law on the deviatoric plane. Therefore, the flow direction n on the deviatoric plane in formula (3) is ij The outer normal direction m of the yield surface in formula (15) can be directly taken as ij , that is, n ij =m ij Therefore, the plastic deviatoric strain It can be expressed as:

[0139]

[0140] (7) Derivation of shear expansion coefficient

[0141] The dilatancy coefficient D is used to describe the relationship between plastic volume strain and plastic shear strain. The results of stress test show that the value of D decreases linearly with the increase of stress ratio, so it can be expressed as:

[0142]

[0143] The test results also show that the value of D decreases with the decrease of void ratio and confining pressure. In addition, D must also meet the requirement that the volume strain of the critical state soil remains unchanged, that is, D(η=M,ψ=0)=0. In summary, the expression of A and B in Equation (23) can be obtained as: B=d0e mψ , Therefore, the expression of the shear dilation coefficient D is:

[0144]

[0145] (7) Total strain increment

[0146] By replacing the loading factor L in formula (14) and the plastic modulus K in formula (21) p , the dilatancy coefficient D in formula (24), the plastic flow direction m on the deviatoric plane in formula (22) ij Substituting into formula (3), we can get the plastic strain increment Combined with the elastic strain increment in formula (9), The total strain increment can be calculated:

[0147]

[0148] Through the above process, all the components required to establish the state-dependent constitutive model are determined. These elements can be integrated to construct the model's stiffness matrix. The derivation process of the elastic-plastic stiffness matrix is as follows:

[0149] The stress ratio increment is expressed as follows according to its definition:

[0150]

[0151] The loading factor L is expressed as:

[0152]

[0153] Among them, m ij represents the normal direction outside the yield surface and is calculated by the following formula:

[0154]

[0155] Combining formulas (3), (25), and (27), the incremental stress-strain relationship of the model is expressed as:

[0156]

[0157] in, is the elastic stiffness tensor.

[0158] Step 3.3: Combine the elastic relationship, yield surface, plastic flow direction, hardening law, and plastic modulus to construct a soil constitutive model that is correlated with the soil state.

[0159] Step 4: Verify the predictive ability of the constructed constitutive model through DEM trial test and triaxial loading test.

[0160] The effectiveness of the constitutive model proposed in this invention is verified by comparing the test results with the model results, including the following:

[0161] Model Validation 1:

[0162] First, a stress test with initial state η0 = 0.5, p0 = 200 kPa and e0 = 0.687 was simulated, and the results are as follows: Figure 3 As shown in Figure 2, the total strain, elastic strain, and plastic strain response envelopes of the DEM results and the model predictions are shown. Figure 3 It can be seen from the experimental results and model simulation results that the model proposed in the present invention can effectively predict the results of the DEM trial test, and the model can accurately predict the response envelope of the total strain, elastic strain and plastic strain.

[0163] Model Validation 2:

[0164] Triaxial tests were carried out under different density, confining pressure and drainage conditions to verify the model's predictive ability. Figure 4 Comparisons were made between drained triaxial test data and model predictions for different initial porosity ratios at confining pressures of p0 = 200 kPa and 500 kPa. The denser specimens exhibited higher peak deviatoric stresses and stronger dilatancy responses, and the model predictions were consistent with the DEM results. Figure 5 Undrained triaxial compression tests at different densities and confining pressures are presented, and DEM data are compared with model predictions to verify that the model is capable of simulating shrinkage and dilatancy behavior under a wide range of initial states.

[0165] To evaluate the performance of the model in multiaxial stress space, Figure 6 The results of a series of drained DEM tests under a confining pressure of p0 = 500 kPa with different intermediate principal stress coefficients b are presented. Two specimens with different initial void ratios e0 = 0.541 and p0 = 0.669 are considered. The relationship between the principal strains ε1, ε2, ε3 and the stress ratio η, as well as the volumetric strain ε v , and the relationship between the principal strain ε1. By comparison, it can be seen that the model proposed in the present invention can effectively capture the three-dimensional stress-strain behavior of the sample, verifying the predictive ability of the model.

[0166] It should be noted that the parts in this embodiment that are the same or similar to those in Example 1 can be referenced to each other and will not be described in detail in this application.

[0167] Example 3:

[0168] Based on Example 2, Example 3 of the present application provides a new system for constructing a soil constitutive model based on a stress trial test, including:

[0169] The analysis module is used to conduct stress test on soil samples using discrete element method and analyze the strain response of soil under stress increments in different directions;

[0170] A derivation module is used to derive key components of the constitutive model, including the yield surface, plastic flow direction, shear dilatancy coefficient, and plastic modulus, based on the response envelope obtained from the stress probe test;

[0171] Establish a module for combining critical state theory to establish state-dependent constitutive models;

[0172] The verification module is used to verify the prediction ability of the constitutive model through DEM trial test and triaxial loading test.

[0173] Specifically, the system provided in this embodiment is a system corresponding to the method provided in Example 2. Therefore, the parts in this embodiment that are the same or similar to those in Example 2 can be referenced to each other and will not be repeated in this application.

Claims

1. A new method for constructing a soil constitutive model based on stress test, characterized in that: include: Step 1: Use the discrete element method to conduct stress test on soil samples and analyze the strain response of soil under stress increments in different directions; Step 2: Based on the response envelope obtained from the stress test, the key components of the constitutive model are derived, including the yield surface, plastic flow direction, shear dilatancy coefficient, and plastic modulus; Step 3: Combine the critical state theory to establish a state-dependent constitutive model; Step 4: Verify the predictive ability of the constitutive model through DEM trial tests and triaxial loading tests.

2. The new method for constructing a soil constitutive model based on stress probing test according to claim 1 is characterized in that: Step 1 includes: Step 1.1, sample preparation: Discrete element method simulation was performed to prepare samples with different porosity ratios by adjusting the inter-particle friction coefficient μ, and the samples were consolidated to different stress states; Step 1.2: Apply a series of stress increments dσ of the same magnitude but different directions to the specimen. r , measure the corresponding strain increment dε r ; Step 1.3, strain decomposition: Use the parallel trial method to measure the total strain increment and elastic strain increment respectively, and calculate the plastic strain increment by the difference.

3. The new method for constructing a soil constitutive model based on stress probing test according to claim 2 is characterized in that: In step 1.2, two types of analysis are used: axisymmetric stress probe tests and deviatoric stress probe tests. For the axisymmetric test, the two normal stress components in the horizontal direction have the same magnitude. In the deviatoric stress probe test, the stress increment is applied on the deviatoric stress plane.

4. The new method for constructing a soil constitutive model based on stress probing test according to claim 3 is characterized in that: Step 2 includes: Step 2.1: Express the plastic strain increment as: Where, is the loading factor, which represents the plastic deviatoric strain increment The size of χ ij is the direction of plastic flow, and the deviatoric strain part n ij and volume part Composition; n ij is the deviatoric strain unit tensor, specified by direction; is the shear dilatancy coefficient; Step 2.2: According to the formula in step 2.1, deduce the partial plastic flow direction n ij and dilatancy coefficient D; Step 2.3: Express the plastic modulus as: Where f is the yield surface, Specified σ ij The direction of the external normal of f, H is a function of the internal state variables related to the hardening rule, K p is the plastic modulus.

5. The new method for constructing a soil constitutive model based on stress probing test according to claim 4 is characterized in that: Step 3 includes: Step 3.

1. Determine the critical state. The critical state refers to the state in which the soil continues to shear and deform while its stress and volume remain unchanged. Step 3.2: Derive the linear constitutive relation, yield surface, hardening law, plastic flow direction, plastic modulus, and dilatancy coefficient; and calculate the total strain increment. Step 3.3: Combine the elastic relationship, yield surface, plastic flow direction, hardening rule and plastic modulus to construct a soil constitutive model with soil state correlation.

6. A new system for constructing soil constitutive models based on stress test, characterized by: Used to perform the method according to any one of claims 1 to 5, comprising: The analysis module is used to conduct stress test on soil samples using discrete element method and analyze the strain response of soil under stress increments in different directions; A derivation module is used to derive key components of the constitutive model, including the yield surface, plastic flow direction, shear dilatancy coefficient, and plastic modulus, based on the response envelope obtained from the stress probe test; Establish a module for combining critical state theory to establish state-dependent constitutive models; The verification module is used to verify the prediction ability of the constitutive model through DEM trial test and triaxial loading test.

7. A computer storage medium, characterized in that The computer storage medium stores a computer program; when the computer program is run on a computer, the computer executes the method according to any one of claims 1 to 5.

8. An electronic device, characterized in that: include: Memory, used to store computer programs; A processor, configured to execute the computer program to implement the method according to any one of claims 1 to 5.

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