True triaxial static force-disturbance viscoelastic plastic damage unified model and construction method

Abstract

The invention discloses a static-disturbance viscoelastic plastic damage unified model construction method under true three-dimensional stress, which comprises the following steps: S1, carrying out a true triaxial static compression test to obtain a strength rule; s2, carrying out a true triaxial disturbance test, and researching a rock disturbance deformation evolution rule; s3, introducing a three-dimensional strength criterion, establishing a plastic yield function, and constructing an elastic-plastic constitutive equation; s4, considering a rock disturbance degradation effect, and constructing a viscoelastic constitutive equation; s5, integrating and constructing a static force-disturbance viscoelastic plastic damage unified model, and establishing a model numeralization method; s6, simulating a static test, verifying the elastic-plastic constitutive equation, and fitting to obtain ductility-brittleness conversion formula parameters; s7, simulating a disturbance test, and verifying the viscoplastic constitutive equation; and S8, sorting model parameters, further carrying out numerical simulation, and checking the prediction effect of the model. The method provides a theoretical basis for mechanical behavior prediction and stability analysis of high-stress deep engineering surrounding rock, and has important engineering application value.

Description

Technical Field

[0001] The present invention relates to the field of rock mechanical properties and engineering research, in particular to a unified static-disturbance viscoelastic-plastic damage model under true three-dimensional stress and a construction method thereof, which is suitable for simulation and analysis of rock mechanical properties under complex stress environments. Background Art

[0002] Deep underground projects operate in a true three-dimensional high geological pressure environment. After excavation, the stress state and stress path of the surrounding rocks undergo significant changes. At the same time, as the tunnel face advances, the dynamic waves generated by the blasting have a dynamic disturbance effect on the previously excavated and damaged surrounding rocks. At present, most mechanical models are based on the mechanical properties of rocks under uniaxial or conventional triaxial compression to construct constitutive models, ignoring the impact of the real three-dimensional stress environment of deep rock mass on the deep rock mass, as well as the changes in the viscoelastic-plastic damage of materials under disturbance. Therefore, a unified model that can comprehensively consider the viscoelastic-plastic damage of materials under static, perturbation and true three-dimensional stress conditions is needed to more accurately predict the performance of engineering structures.

[0003] Most of the existing rock constitutive models are based on classic two-dimensional strength criteria such as the Mohr-Coulomb criterion and the Drucker-Prager criterion. Although they are practical to a certain extent, they have limitations in dealing with three-dimensional stress problems. A few scholars have constructed some rock constitutive models based on single traditional static tests or perturbation tests and through three-dimensional strength standards such as Mogi-Coulomb and 3D Hoek-Brown. However, during tunnel excavation, rocks are in a stress environment of three-dimensional stress redistribution, and static damage evolution and dynamic perturbation degradation exist simultaneously inside the rocks. These models are difficult to characterize the three-dimensional strength law of rocks under the combined action of static and perturbation, and also ignore the perturbation degradation effect and ductile-brittle transition law of rocks induced by three-dimensional stress. At present, there is a lack of a unified model that can comprehensively consider the viscoelastic-plastic damage of materials under static, perturbation and true three-dimensional stress conditions, so as to more accurately characterize the ductile-brittle transition characteristics and perturbation deformation evolution characteristics of rocks under static-perturbation coupling.

[0004] In view of the above shortcomings, the present invention proposes a construction and numerical method for a unified static-disturbance viscoelastic-plastic damage model under true three-dimensional stress. Based on the results of true triaxial static compression test and multi-level disturbance compression test, the method proposes a strength criterion applicable to true three-dimensional dynamic and static combined stress conditions. On the basis of this strength criterion, a unified static-disturbance viscoelastic-plastic damage model under true three-dimensional stress is further constructed, which takes into account the ductile-brittle three-dimensional stress effect and the disturbance degradation effect. Based on the finite element software, a corresponding numerical calculation program is developed to provide a theoretical basis for the prediction of surrounding rock damage disasters and long-term stability analysis of high-stress deep engineering. Summary of the invention

[0005] The purpose of the present invention is to provide a method for constructing a unified static-disturbance viscoelastic-plastic damage model under true three-dimensional stress, to predict the mechanical properties of rock under true triaxial disturbance stress, and to provide a theoretical basis for the prediction of surrounding rock damage disasters and long-term stability analysis of high-stress deep engineering.

[0006] In order to achieve the above technical objectives, the present invention provides a method for constructing a unified static-disturbance viscoelastic-plastic damage model under true three-dimensional stress, the steps of which include:

[0007] S1. Carry out true triaxial static compression tests under different σ2 and σ3 conditions to obtain basic mechanical parameters such as peak strength and elastic modulus of rock, analyze the strength law of rock under true triaxial static compression and the ductile-brittle evolution characteristics of rock stress-strain curve.

[0008] S2. According to the rock strength obtained from the static compression test, a true triaxial multi-stage disturbance test scheme is designed under different σ2 and σ3 conditions, and the isochronal curve cluster is used to determine the critical strength of rock disturbance, and the evolution characteristics of rock disturbance deformation and the critical strength of rock disturbance σ are studied. cs and the disturbance failure stress σ d evolution law.

[0009] S3. Construct an elastoplastic constitutive equation considering true three-dimensional stress and damage effects: Based on the results of true triaxial static tests, a three-dimensional strength criterion is used to characterize the strength law of rock; three-dimensional stress-induced ductility-brittleness conversion formulas β(σ2, σ3) and ζ(σ2, σ3) are proposed, and a nonlinear behavior function h describing the plastic hardening and damage softening of rock materials is constructed. p , and based on this, a three-dimensional plastic yield function F is established; based on the rock damage evolution law under true three-dimensional stress, a damage evolution equation F that reflects ductility and brittleness is constructed d .

[0010] S4. Construct a viscoelastic constitutive equation that introduces true three-dimensional stress perturbation effect: Refer to the plastic yield function F in step S3 to establish the perturbation yield function F v and the perturbation potential function G v ; Based on Perzyna overstress theory, the disturbance multiplier dλ is established v At the same time, according to the evolution characteristics of rock disturbance strain, the disturbance parameter η(N) related to the number of disturbances and the rock disturbance accelerated degradation factor D are established. v (N).

[0011] S5. Integrate the constitutive equations in step S3 and step S4 into a static-disturbance unified viscoelastic-plastic damage model, and compile the model into a user subroutine UMAT of the finite element software ABAQUS through Fortran language. Verify and adjust the proposed model through simulation.

[0012] S6. By using the numerical simulation method of the model established in step S5, the true triaxial static compression test of rock in step S1 is simulated to verify the elastic-plastic constitutive equation established in step S3; at the same time, the key parameters β and ζ of the rock plastic evolution under different three-dimensional stress conditions are obtained, and the parameters of the three-dimensional stress-induced ductility-brittleness conversion formula are obtained by fitting.

[0013] S7, through the numerical simulation method of the model established in step S5, simulate the true triaxial multi-stage disturbance test of rock in step S2, verify the viscoelastic constitutive equation established in step S4, and obtain the key parameter A of rock disturbance strain evolution under different three-dimensional stress conditions v , B v and C v .

[0014] S8. Simulate the true triaxial static compression test of rock under different σ2 and σ3 conditions, obtain the corresponding parameters β and ζ through the ductility-brittleness parameter prediction formula in step S6 for simulation, and verify the rock static prediction effect of the model; simulate the true triaxial multi-stage disturbance compression experiment under the same σ2 and σ3 different disturbance stress conditions to verify the prediction effect of the model on the rock disturbance deformation evolution.

[0015] In step S1, the true triaxial static compression peak strength σ of the rock under different σ2 and σ3 conditions is calculated. c and rock elastic modulus E;

[0016] In step S2, based on the peak intensity σ in step S1 p , gradually load σ1 to 0.4σ p , 0.6σ p , 0.7σ p , 0.8σ p , 0.85σ p , 0.90σ p , 0.925σ p , 0.95σ p , 0.975σ p ...Equal stress levels (increase 0.025σ for each level) pAfter σ1 is loaded to the specified stress level, a sinusoidal stress wave disturbance with a frequency of 0.5 Hz and an amplitude of 1 MPa is carried out, with 100 cycles per level, until the rock is destroyed; for each level of disturbance, ten nodes with the same disturbance time are taken and the corresponding strain values ​​are counted. According to the stress and strain values ​​corresponding to the same disturbance time, an isochronous curve cluster is drawn. The stress value corresponding to the turning point where the curves in the isochronous curve cluster are obviously separated is the critical strength of the rock disturbance σ cs .

[0017] The method for establishing the elastic-plastic constitutive equation in step S3 is:

[0018] S3.1. Based on the analysis of the static test data in step S1, it is found that the peak strength of rock under different three-dimensional stresses can better meet the modified Weibols-Cook strength criterion:

[0019] q=a wc +b wc p+c wc p 2 (1)

[0020]

[0021] Among them, p is the average principal stress; q is the generalized shear stress; σ1, σ2, σ3 are the maximum principal stress, the intermediate principal stress, and the minimum principal stress, respectively; a wc 、b wc 、c wc These are intensity parameters.

[0022] S3.2. Based on the modified Weibols-Cook strength criterion, the function h is introduced to describe the nonlinear behavior of plastic hardening and damage softening of rock materials. p , and the plastic yield function F is established:

[0023]

[0024] Among them, the intensity parameter a wc 、b wc and c wc It can be expressed as:

[0025]

[0026]

[0027]

[0028] In the formula, C0, Ψ0 and C c and cohesion c and internal friction angle Related, there are the following relationships:

[0029]

[0030]

[0031]

[0032] h p is a function of the equivalent plastic shear strain and the damage variable:

[0033]

[0034] in Controlling initial yield surface characteristics; Controlling plastic yield surface characteristics; γ p is the equivalent plastic shear strain; β controls the nonlinear behavior of pre-peak plastic hardening; ζ controls the damage rate, which can describe the nonlinear behavior characteristics of post-peak damage softening of rock. In order to control the ductility and brittleness conversion of rock with three-dimensional stress, β and ζ are replaced by the three-dimensional stress-induced ductility and brittleness conversion formula: This can improve the plastic yield function and further control the ductile-brittle transformation of rock.

[0035] S3.3. Establish plastic potential function:

[0036] G=q+b wcg pc wcg p 2 (11)

[0037] When taking b wcg =b wc And c wcg =c wc It is the associated flow law when , otherwise it is the non-associated flow law.

[0038] S3.4. Calculation of plastic multiplier dλ from plastic potential function p :

[0039] According to Hooke's law, the expression of stress increment tensor is:

[0040] dσ=C(ω):(dε-dε p ) (12)

[0041] In addition, the plastic increment dε of the rock in the plastic stage p It can be determined according to the plastic flow law:

[0042]

[0043]

[0044]

[0045] Among them, dλ p is the plasticity multiplier, which is non-negative. When the rock is in a plastic stress state, the stress does not pass through the yield surface, but falls on the yield surface (F = 0), that is, the plastic consistency condition dF = 0 is satisfied:

[0046]

[0047] Substituting (5) and (6) into (9) yields the plastic multiplier dλ: p :

[0048]

[0049] S3.5. Establish the damage evolution equation F that reflects ductility and brittleness d :

[0050] F d (Y d ,ω)=ω c th(B ω Y d )-ω (18)

[0051]

[0052] Among them, B ω The value is 1; c is the maximum value of the damage variable.

[0053] For simplicity, it is assumed that the plastic behavior and damage behavior of rock occur simultaneously. Similar to plasticity, the damage variable needs to satisfy the damage consistency condition:

[0054]

[0055]

[0056] The method for constructing the viscoelastic constitutive equation in step S4 is:

[0057] S4.1. The perturbation yield surface can be regarded as a delayed plastic yield surface. The perturbation yield function F is established. v and potential function G v :

[0058] F v =qa wcv α v +b wcv pc wcv p 2 (twenty two)

[0059] G v =q+b wcv pcwcv p 2 (twenty three)

[0060]

[0061] Among them, the intensity parameter a of the disturbance test wcv 、b wcv 、c wcv Obtained by fitting the disturbance failure stress of the disturbance test.

[0062] S4.2. Based on the potential function G v The relationship between the number of disturbances and time (N = ft) is used to establish the irreversible strain equation of disturbance:

[0063]

[0064] S4.3. Based on Perzyna overstress theory, the disturbance multiplier expression is established:

[0065]

[0066] Finally, the perturbation irreversible strain is written as:

[0067]

[0068] S4.4. Based on the evolution characteristics of the deceleration stage and the constant velocity stage of the rock disturbance test, the disturbance parameter equation is established:

[0069] η v (N) = η0[(A v +1)-A v exp(-B v N)] (28)

[0070] Among them, A v Control perturbation constant speed evolution behavior, B v Controlling perturbations slows down evolutionary behavior.

[0071] S4.5. Analysis of rock disturbance test results shows that when the rock disturbance stress exceeds the critical disturbance strength σ cs When the rock enters the disturbance acceleration stage, the degradation factor D v (N) Control parameter η v (N) Rapid degradation, when the rock disturbance stress does not exceed the critical stress σ L When D v (N) has no effect and takes the value of zero:

[0072]

[0073] Among them, C v Controlling the evolution characteristics of rock disturbance acceleration stage, Dv (N) evolves between 0-0.999.

[0074] Finally, the disturbance strain parameter can be expressed as:

[0075] η v (N) = (1-D v )η0[(A v +1)-A v exp(-B v N)] (30)

[0076] The method for compiling the static-disturbance viscoelastic-plastic damage unified model under true three-dimensional stress into a numerical subroutine in step S5 is:

[0077] S5.1. Divide the total strain into elastic strain, plastic strain and perturbation irreversible strain, and perform elastic prediction first:

[0078] ε=ε e +ε p +ε v (31)

[0079]

[0080] S5.2. For static elastoplastic evolution, if the stress level does not exceed the plastic yield surface F, the total strain is calculated elastically; if the stress level exceeds the plastic yield surface F, the plastic multiplier dλ is calculated p , damage increment dω k+1 and plastic strain increment dε p(k+1) , plastic correction is performed on the stress:

[0081]

[0082]

[0083] σ k+1 =σ k+1 -C(ω k+1 )dε p(k+1) (35)

[0084]

[0085] S5.3. For perturbed viscoelastic-plastic evolution, if the stress level does not exceed the perturbation yield surface F v , the total strain is calculated elastically; if the stress level exceeds the perturbation yield surface F v , then viscosity correction is performed; if the stress level after viscosity correction does not exceed the plastic yield surface, the variables are updated; if the stress level after viscosity correction exceeds the plastic yield surface, the stress is further corrected according to step C2 and then the variables are updated:

[0086]

[0087]

[0088] The beneficial effects of the present invention are:

[0089] 1. The present invention adopts the modified Weibols-Cook strength criterion, which can better reflect the strength law of rock under true triaxial static-disturbance coupling.

[0090] 2. The three-dimensional stress-induced ductility-brittleness conversion formula of rock established in the present invention can characterize the influence of three-dimensional stress effect on the evolution of rock damage, and can effectively predict the nonlinear ductility-brittleness conversion characteristics of rock under true triaxial stress.

[0091] 3. The present invention can well demonstrate the dynamic disturbance degradation effect of rock under three-dimensional stress induction, and can completely characterize the evolution characteristics of the three stages of attenuation stage, constant velocity stage and acceleration stage in the rock disturbance deformation process under true triaxial stress.

[0092] 4. After secondary development, the model constructed by the present invention can be applied to the long-term stability analysis and prediction of corresponding projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0093] Figure 1 Build a flow chart for the model;

[0094] Figure 2 This is the true triaxial multi-stage disturbance test scheme diagram;

[0095] Figure 3 Define graphs for rock peak strength, elastic modulus and Poisson's ratio;

[0096] Figure 4 Define a graph for the perturbation critical intensity;

[0097] Figure 5 It is the strength parameter fitting diagram of rock static and multi-level disturbance tests;

[0098] Figure 6 This is the flow chart of the algorithm for digitizing the model;

[0099] Figure 7 is the fitting diagram of ductile-brittle conversion function;

[0100] Figure 8 This is a comparison chart between the static test results and the simulation results;

[0101] Fig. 9 This is a static prediction simulation effect diagram;

[0102] Fig.10 This is a comparison chart between the disturbance experiment results and the simulation results;

[0103] Fig.11 This is a diagram of the disturbance prediction simulation effect. DETAILED DESCRIPTION

[0104] The specific implementation of the present invention is described below in conjunction with the accompanying drawings, but the present invention is not limited to the scope of the specific implementation. It should be noted that all creations based on or dependent on the present invention are within the protection scope of the present invention.

[0105] Embodiment 1:

[0106] This embodiment provides a method of constructing and verifying the accuracy and rationality of a unified static-disturbance viscoelastic-plastic damage model under true three-dimensional stress using sandstone as a rock sample.

[0107] refer to Figure 1 , Figure 1 The flowchart of constructing a unified static-perturbation viscoelastic-plastic damage model under true three-dimensional stress is shown in Fig. Figure 1 As shown, the method includes steps S1 to S10.

[0108] In step S1, a true triaxial static compression test is performed on the sandstone at different stress levels to determine the peak strength σ of the rock. p and elastic modulus E0, such as Figure 3 Point A in the figure represents the rock crack closure stress σ cc , is the point where the original cracks inside the rock are continuously closed after being compressed, the elastic modulus is continuously increased, and then the cracks are completely closed, and the elastic modulus begins to stabilize, which can generally be taken as 30% of the peak strength; Point B represents the crack initiation stress σ ci , is the point where new microcracks begin to form when the rock is subjected to pressure. It can generally be taken as 50% of the peak strength. The AB segment can be regarded as a linear elastic region. Point C represents the peak strength σ p The elastic modulus E0 of sandstone can be determined by the slope of the linear elastic stage (segment AB) (Δσ1 / Δε1); the Poisson's ratio υ can be determined by the ratio of the lateral strain increment Δε3 to the axial strain increment Δε1 in the linear elastic stage (Δε3 / Δε1).

[0109] In step S2, according to the rock strength obtained from the static compression test, a true triaxial multi-stage disturbance test scheme under different σ2 and σ3 conditions is designed as follows: Figure 2 The isocyclic curve cluster method used in the present invention to determine the critical strength of rock disturbance is as follows: ten nodes of the same disturbance period are taken for each level of disturbance and the corresponding strain values ​​are counted. According to the stress and strain values ​​corresponding to the same disturbance period, an isocyclic curve cluster is drawn. The stress value corresponding to the turning point where the curves in the isocyclic curve cluster are obviously separated is the critical strength of rock disturbance σ cs , such as Figure 4 Table 1 shows the elastic modulus E0, Poisson's ratio v, and peak strength σ of rocks under different true triaxial stress conditions. p , disturbance failure stress σ d and the critical intensity of disturbance σ cs .

[0110] In step S3, the rock peak strength σ obtained from the true triaxial static compression test is p The corresponding generalized shear stress q and average stress p are calculated, and a qp scatter plot is drawn. The strength parameter a is obtained by fitting the modified Weibols-Cook strength criterion. wc =20.16, b wc =1.74 and c wc =1.93e -16 ,like Figure 5 As shown. The plastic yield function equation F and potential function G are obtained:

[0111]

[0112] G=q+1.74p-1.93e -16 p 2

[0113] In step S4, the rock disturbance failure stress σ obtained from the true triaxial multi-stage disturbance test is d The corresponding generalized shear stress q and average stress p are calculated, and a qp scatter plot is drawn. The strength parameter a is obtained by fitting the modified Weibols-Cook strength criterion. wc =28.486, b wc =1.502 and c wc =0.02462, such as Figure 5 As shown. The perturbation yield function F is obtained v and potential function G v :

[0114]

[0115] G v =q+1.502p-0.02462p 2

[0116] σ k+1 =σ k+1 -C(ω k ):dε v(k+1)

[0117] In step S5, the constitutive model constructed in steps S3 and S4 is compiled into a numerical program. Figure 6 shown.

[0118] When the stress level exceeds the perturbation yield surface:

[0119]

[0120] Compute the perturbation multiplier:

[0121]

[0122] Apply a viscous correction to the stresses:

[0123]

[0124] When the stress level exceeds the plastic yield surface:

[0125]

[0126] Compute the plasticity multiplier:

[0127]

[0128] Apply plastic correction to stresses:

[0129]

[0130] Injury Update:

[0131]

[0132]

[0133] ω k+1 =ω k +dω k

[0134] In step S6, the model parameters and basic mechanical parameters obtained by simulating the true triaxial static test are statistically shown in Table 2. And the key parameters β and ζ of rock plastic evolution under different stress conditions obtained by simulation are used to draw a three-dimensional scatter plot of the key parameters β and ζ under different stress conditions (σ2, σ3), as shown in Table 2. Figure 7 As shown. The final fitting results are the three-dimensional stress-induced ductility-brittleness conversion formulas β(σ2, σ3) and ζ(σ2, σ3), respectively:

[0135]

[0136]

[0137] Among them, σ2 and σ3 are the intermediate principal stress and the minimum principal stress respectively.

[0138] In step S7, the key parameters of disturbance strain evolution obtained by simulating the true triaxial multi-stage disturbance test are statistically shown in Table 3.

[0139] In step S8, the true triaxial static compression test of rock under different σ2 and σ3 conditions is simulated, and the corresponding parameters β and ζ are obtained by the three-dimensional stress-induced ductility-brittleness conversion formula for simulation, and the characterization ability and prediction effect of the model proposed in the present invention on the evolution of static compression deformation of rock are obtained as follows: Figure 8 and Fig. 9 By simulating true triaxial multi-stage disturbance compression experiments under the same σ2 and σ3 but different disturbance stress conditions, the characterization capability and prediction effect of the model proposed in the present invention on the evolution of rock disturbance deformation are obtained as shown in Fig.10 and Fig.11 shown. Table 1 Disturbance failure stress σ of sandstone under true triaxial disturbance stress d and the critical intensity of disturbance σ cs Table 2 Parameters of the elastic-plastic part of the unified viscoelastic-plastic damage model Table 3 Model parameters of dynamic disturbance part of unified viscoelastic-plastic damage model

[0140] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are included in the protection scope of the present invention.

Claims

1. A unified static-perturbation viscoelastic-plastic damage model construction method under true three-dimensional stress, characterized by: The following steps are involved: S1. Carry out true triaxial static compression tests under different σ2 and σ3 conditions, and obtain the basic mechanical parameters of rock (initial yield strength σ y , peak intensity σ p , crack closure stress σ cc , crack initiation stress σ ci , residual strength σ r , Poisson's ratio υ, elastic modulus E0), analyze the strength law of rock under true triaxial static compression and the ductile-brittle evolution characteristics of rock stress-strain curve; S2, rock peak strength σ obtained from static compression test c , design a true triaxial multi-stage disturbance test scheme corresponding to σ2 and σ3 conditions, use a cluster of isocyclic curves to determine the critical strength of rock disturbance, and study the evolution characteristics of rock disturbance deformation and the evolution law of rock disturbance critical strength and disturbance failure stress; S3. Construct a unified static-disturbance viscoelastic-plastic damage model under true three-dimensional stress: Based on true triaxial static test analysis, the modified Weibols-Cook strength criterion is used to characterize the strength law of rock, and the function h is introduced to describe the nonlinear behavior of plastic hardening and damage softening of rock materials. p , establish a three-dimensional plastic yield function F, and construct a ductile-brittle damage evolution equation F based on the rock damage evolution law under true three-dimensional stress d , as follows: S3.

1. Based on the true triaxial static test data results in step S1, the modified Weibols-Cook strength criterion is used to fit the peak strength of rock under true triaxial static: q=a wc +b wc p+c wc p 2 S3.

2. Based on the modified Weibols-Cook strength criterion, the function h is introduced to describe the nonlinear behavior of plastic hardening and damage softening of rock materials. p , establish the plastic yield function F: S3.

3. Establishing the damage evolution equation F that reflects ductility and brittleness d : F d (Y d ,ω)=ω c th(B ω Y d )-ω Among them, β controls the nonlinear behavior of pre-peak plastic hardening, ζ controls the damage rate, and describes the nonlinear behavior characteristics of post-peak damage softening of rock. In order to control the ductility and brittleness conversion of rock with three-dimensional stress, β and ζ are replaced by the three-dimensional stress-induced ductility and brittleness conversion formula respectively: S4. Referring to the plastic yield function F in step S3, establish the perturbation yield function F v and the perturbation potential function G v ; Based on Perzyna overstress theory, the disturbance multiplier dλ is established v At the same time, according to the evolution characteristics of rock disturbance strain, the disturbance parameter η(N) related to the number of disturbances and the rock disturbance accelerated degradation factor D are established. v (N), as follows: S4.

1. Consider the perturbation yield surface as a delayed plastic yield surface and establish the perturbation yield function F v and potential function G v : F v =q-a wcv α v +b wcv p-c wcv p 2 G v =q+b wcv p-c wcv p 2 S4.

2. Based on the potential function G v The relationship between the number of disturbances and time (N = ft) is used to establish the irreversible strain equation of disturbance: S4.

3. Based on Perzyna overstress theory, the perturbation multiplier expression is established: S4.

4. Based on the evolution characteristics of the deceleration stage and the constant velocity stage of the rock disturbance test, the disturbance strain parameter equation is established: or v (N)=η0[(A v +1)-A v exp(-B v N)] Analyze the evolution characteristics of the acceleration stage of rock disturbance. When the rock disturbance stress exceeds the critical intensity of disturbance σ cs When the rock enters the disturbance acceleration stage, the degradation factor D v (N) Control parameter η v (N) Rapid degradation, when the rock disturbance stress does not exceed the critical stress σ L When D v (N) has no effect and takes the value of zero: Among them, C v Controlling the evolution characteristics of rock disturbance acceleration stage, D v (N) evolves between 0-0.

999. Finally, the disturbance strain parameter equation can be expressed as: or v (N)=(1-D v )η0[(A v +1)-A v exp(-B v N)]. S5, integrating the constitutive equations in step S3 and step S4 into a static-disturbance unified viscoelastic-plastic damage model, and compiling the model into a user subroutine UMAT of finite element software ABAQUS through Fortran language, and establishing a numerical simulation method of the model; S6. By using the numerical simulation method of the static-disturbance unified viscoelastic-plastic damage model established in step S5, the true triaxial static compression test of rock in step S1 is simulated to verify the elastic-plastic constitutive equation considering true three-dimensional stress and damage effect established in step S3; at the same time, the key parameters β and ζ of the rock plastic evolution under different three-dimensional stress conditions are obtained, and the parameters of the three-dimensional stress-induced ductility-brittleness conversion formula are obtained by fitting; S7, through the numerical simulation method of the model established in step S5, simulate the true triaxial multi-stage disturbance test of rock in step S2, verify the viscoelastic constitutive equation established in step S4, and obtain the key parameter A of rock disturbance strain evolution under different three-dimensional stress conditions v , B v and C v ; S8. True triaxial static compression tests and true triaxial multi-stage perturbation compression tests of rocks simulating different stress conditions are carried out to verify the prediction effect of the model.

2. The method for constructing a unified static-disturbance viscoelastic-plastic damage model under true three-dimensional stress according to claim 1, characterized in that: In step S5, the numerical method of the static-disturbance unified viscoelastic-plastic damage model is as follows: For static elastoplastic evolution, if the stress level does not exceed the plastic yield surface F, the total strain is calculated elastically; if the stress level exceeds the plastic yield surface F, the plastic multiplier dλ is calculated p , damage increment dω k+1 and plastic strain increment dε p(k+1) , a plastic correction is made to the stress: s k+1 =s k+1 -C(ω k+1 )d p(k+1) For the perturbed viscoelastic-plastic evolution, if the stress level does not exceed the perturbation yield surface F v , the total strain is calculated elastically; if the stress level exceeds the perturbation yield surface F v , a viscosity correction is performed; if the stress level after viscosity correction does not exceed the plastic yield surface, the variables are updated; if the stress level after viscosity correction exceeds the plastic yield surface, the stress is plastically corrected before updating the variables:

3. The method for constructing a unified static-disturbance viscoelastic-plastic damage model under true three-dimensional stress according to claim 1, characterized in that: In step S8, the method of simulating the rock true triaxial static compression test and rock true triaxial multi-stage disturbance compression test under different stress conditions to verify the model prediction effect is as follows: Simulate the true triaxial static compression test of rock under different σ2 and σ3 conditions, obtain the corresponding parameters β and ζ through the three-dimensional stress-induced ductility-brittleness conversion formula in step S6 for simulation, and verify the rock static prediction effect of the model; take the disturbance strain parameter A under the same σ2 and σ3 v , B v and C v , simulate the true triaxial multi-stage disturbance compression experiment under the same σ2, σ3 and different disturbance stress conditions to verify the prediction effect of the model on the evolution of rock disturbance deformation.

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