Unified Model of Static-Disturbance Visco-Elasto-Plastic Damage under True Triaxial Conditions and Its Construction Method

Abstract

The present invention discloses a method for constructing a unified static-disturbance viscoelastic-plastic damage model under true three-dimensional stress, comprising the following steps: S1. Conduct a true triaxial static compression test to obtain the strength law; S2. Conduct a true triaxial disturbance test to study the evolution law of rock disturbance deformation; S3. Introduce a three-dimensional strength criterion, establish a plastic yield function, and construct an elastoplastic constitutive equation; S4. Consider the rock disturbance deterioration effect and construct a viscoelastic constitutive equation; S5. Integrate and construct a unified static-disturbance viscoelastic-plastic damage model, and establish a numerical method for the model; S6. Simulate the static test, verify the elastoplastic constitutive equation, and fit to obtain the parameters of the ductile-brittle transition formula; S7. Simulate the disturbance test and verify the viscoplastic constitutive equation; S8. Organize the model parameters, further conduct numerical simulations, and test the prediction effect of the model. The present invention provides a theoretical basis for predicting the mechanical behavior and stability analysis of surrounding rocks in high-stress deep engineering, 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 triaxial stress and a construction method thereof, which is applicable to the simulation and analysis of rock mechanical properties under complex stress environments. Background Technique

[0002] Deep underground engineering operates in a truly three-dimensional high geostatic pressure environment. After excavation, the stress state and stress path of the surrounding rock change significantly. At the same time, as the tunnel face advances, the dynamic waves generated by blasting have a dynamic disturbance effect on the previously excavated and damaged surrounding rock. Currently, most mechanical models construct constitutive models based on the mechanical properties of rocks under uniaxial or conventional triaxial compression, ignoring the influence of the true three-dimensional stress environment of deep rock masses on deep rock masses and 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, disturbance, and true triaxial stress conditions is needed to more accurately predict the performance of engineering structures.

[0003] Most existing rock constitutive models are based on classical two-dimensional strength criteria such as the Mohr-Coulomb criterion and the Drucker-Prager criterion, etc. Although they have certain practicality, 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 disturbance tests and through three-dimensional strength criteria such as the Mogi-Coulomb and 3D Hoek-Brown. During the tunneling process, the rock is in a stress environment of three-dimensional stress redistribution, and there are both static damage evolution and dynamic disturbance deterioration inside the rock. These models are difficult to characterize the three-dimensional strength law of rocks under the combined action of static and disturbance, and also ignore the disturbance deterioration effect and the ductile-brittle transition law of rocks induced by three-dimensional stress. Currently, there is a lack of a unified model that can comprehensively consider the viscoelastic-plastic damage of materials under static, disturbance, and true triaxial stress conditions to more accurately characterize the ductile-brittle transition characteristics and disturbance deformation evolution characteristics of rocks under the static-disturbance coupling action.

[0004] Aiming at the above deficiencies, the present invention proposes a construction and numerical method for a unified static-disturbance viscoelastic-plastic damage model under true triaxial stress. Based on the results of true triaxial static compression tests and multi-level disturbance compression tests, a strength criterion applicable to true three-dimensional static-dynamic combined stress conditions is proposed. On the basis of this strength criterion, a unified static-disturbance viscoelastic-plastic damage model under true triaxial stress considering the ductile-brittle three-dimensional stress effect and disturbance deterioration effect is further constructed, and a corresponding numerical calculation program is developed based on finite element software, providing a theoretical basis for the prediction of surrounding rock failure disasters and long-term stability analysis in high-stress deep engineering. Summary of the Invention

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

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

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

[0008] S2. According to the rock strength obtained from the static compression test, correspondingly design true triaxial multi-stage disturbed test schemes under different conditions of σ2 and σ3, and use the isochronous curve clusters to determine the critical strength of rock disturbance, study the evolution characteristics of rock disturbance deformation and the evolution laws of the critical strength σ cs and the disturbed failure stress σ d of the rock.

[0009] S3. Construct an elastoplastic constitutive equation considering true three-dimensional stress and damage effects: Based on the results of true triaxial static tests, use a three-dimensional strength criterion to characterize the strength law of the rock; propose three-dimensional stress-induced ductile-brittle conversion formulas β(σ2, σ3) and ζ(σ2, σ3), construct a non-linear behavior function h p describing the plastic hardening and damage softening of the rock material, and establish a three-dimensional plastic yield function F based on this; construct a ductile-brittle damage evolution equation F d based on the rock damage evolution law under true three-dimensional stress.

[0010] S4. Construct a viscoelastic constitutive equation introducing the disturbance effect of true three-dimensional stress: Refer to the plastic yield function F in step S3, establish a disturbed yield function F v and a disturbed potential function G v ; based on the Perzyna overstress theory, establish a disturbed multiplier dλ v ; at the same time, according to the evolution characteristics of rock disturbance strain, establish a disturbance parameter η(N) related to the number of disturbances and a rock disturbance accelerated deterioration factor D 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) pTo the rock disturbance and failure). After σ1 is loaded to the specified stress level, a sinusoidal stress wave with a frequency of 0.5 Hz and an amplitude of 1 MPa is applied for disturbance. Each level of disturbance is applied for 100 cycles, and the disturbance is applied step by step until the rock fails; for each level of disturbance, ten nodes with the same disturbance time are selected and the corresponding strain values are statistically analyzed. According to the stress and strain values corresponding to the same disturbance time, an isochronous curve cluster is plotted. The stress value corresponding to the obvious turning point of the curve separation in the isochronous curve cluster is the disturbance critical strength σ of the rock cs 。

[0017] The method for establishing the elastoplastic constitutive equation in step S3 is as follows:

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

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

[0020]

[0021] where p is the mean principal stress; q is the generalized shear stress; σ1, σ2, and σ3 are the maximum principal stress, intermediate principal stress, and minimum principal stress respectively, and a wc , b wc , c wc are all strength parameters.

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

[0023]

[0024] where the strength parameters a wc , b wc and c wc can be expressed as:

[0025]

[0026]

[0027]

[0028] In the formula, C0, Ψ0, and C c are related to the cohesion c and the internal friction angle and have the following relationship:

[0029]

[0030]

[0031]

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

[0033]

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

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

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

[0037] When taking b wcg = b wc and c wcg = c wc it is associated flow, otherwise it is non-associated flow rule.

[0038] S3.4. Deduce the plastic multiplier dλ from the plastic potential function p :

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

[0040] dσ = C(ω):(dε - dε p ) (12)

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

[0042]

[0043]

[0044]

[0045] where dλ p is the plastic multiplier, which is non - negative. When the rock is in the plastic stress state, the stress does not cross the yield surface but lies on the yield surface (F = 0), that is, the plastic consistency condition dF = 0 is satisfied:

[0046]

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

[0048]

[0049] S3.5. Establish the equation F reflecting the evolution of ductile - brittle damage d :

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

[0051]

[0052] where B ω takes the value of 1; ω c is the maximum value of the damage variable.

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

[0054]

[0055]

[0056] The method for constructing the visco - elastic constitutive equation in step S4 is as follows:

[0057] S4.1. The perturbed yield surface can be regarded as a lagged plastic yield surface. Establish the perturbed yield function F v and the potential function G v :

[0058] F v = q - a wcv α v + b wcv p - c wcv p 2 (22)

[0059] G v = q + b wcv p - cwcv p 2 (23)

[0060]

[0061] Among them, the intensity parameters a wcv , b wcv , c wcv of the disturbance test are obtained by fitting the disturbance failure stress of the disturbance test.

[0062] S4.2. Establish a disturbance irreversible strain equation based on the potential function G v and the relationship between the number of disturbance cycles and time (N = ft):

[0063]

[0064] S4.3. Based on the Perzyna overstress theory, establish an expression for the disturbance multiplier:

[0065]

[0066] Finally, the disturbance 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, establish a disturbance parameter equation:

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

[0070] Among them, A v controls the disturbance constant velocity evolution behavior, and B v controls the disturbance deceleration evolution behavior.

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

[0072]

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

[0074] Finally, the disturbed 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 of compiling the static - disturbed visco - elastoplastic damage unified model under true three - dimensional stress into a numerical subroutine in step S5 is as follows:

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

[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, then calculate the plastic multiplier dλ p , the damage increment dω k+1 and the plastic strain increment dε p(k+1) , and perform plastic correction 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 disturbed visco - elastoplastic evolution, if the stress level does not exceed the disturbed yield surface F v , then the total strain is calculated elastically; if the stress level exceeds the disturbed yield surface F v , then perform viscous correction; if the stress level does not exceed the plastic yield surface after viscous correction, update the variables; if the stress level exceeds the plastic yield surface after viscous correction, then further correct the stress according to step C2 and then update the variables:

[0086]

[0087]

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

[0089] 1. The modified Weibols-Cook strength criterion adopted by the present invention can better reflect the strength law of rocks under the true triaxial static-disturbance coupling action.

[0090] 2. The three-dimensional stress-induced brittle-ductile transition formula of rocks established by the present invention can characterize the influence of the three-dimensional stress effect on the damage evolution of rocks, and can effectively predict the non-linear brittle-ductile transition characteristics of rocks under true triaxial stress.

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

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

[0093] Figure 1 is a flow chart for model construction;

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

[0095] Figure 3 is a diagram for defining the peak strength, elastic modulus and Poisson's ratio of rocks;

[0096] Figure 4 is a diagram for defining the disturbance critical strength;

[0097] Figure 5 is a diagram for fitting the strength parameters of the static and multi-stage disturbance tests of rocks;

[0098] Figure 6 is a flow chart of the numerical algorithm of the model;

[0099] Figure 7 is a diagram for fitting the brittle-ductile transition function;

[0100] Figure 8 is a diagram for comparing the static test results with the simulation results;

[0101] Figure 9 is a diagram of the static prediction simulation effect;

[0102] Figure 10 is a diagram for comparing the disturbance test results with the simulation results;

[0103] Figure 11 It is the simulation effect diagram of disturbance prediction. Specific implementation manners

[0104] The following describes the specific implementation manners of the present invention in conjunction with the accompanying drawings, but the present invention is not limited to the scope of the specific implementation manners. It should be noted here that those created on the basis of the present invention or created by relying on the present invention are within the protection scope of the present invention.

[0105] Example 1:

[0106] This example provides a sandstone as a rock specimen to construct and verify the accuracy and rationality of the unified static-disturbance viscoelastic-plastic damage model under true triaxial stress.

[0107] Reference Figure 1 , Figure 1 shows the construction flow chart of the unified static-disturbance viscoelastic-plastic damage model under true triaxial stress. As Figure 1 shown, the method includes steps S1 to S10.

[0108] In step S1, a true triaxial static compression test is performed on the sandstone under different stress levels to determine the peak strength σ p and elastic modulus E0 of the rock, as Figure 3 shown. Point A in the figure represents the rock crack closure stress σ cc , which is the point where the internal primary cracks of the rock continuously close under compression and the elastic modulus continuously increases. Subsequently, the cracks are completely closed and the elastic modulus begins to stabilize. Generally, it can be taken as 30% of the peak strength; Point B represents the initial cracking stress σ ci , which is the point where the rock begins to generate new microcracks under pressure. Generally, it can be taken as 50% of the peak strength. The AB section can be regarded as the linear elastic region; Point C represents the peak strength σ p . The elastic modulus E0 of the sandstone can be determined by the slope of the linear elastic stage (AB section) (Δσ1 / Δε1); the Poisson's ratio υ can be determined by the ratio of the lateral strain increment Δε3 and 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-level disturbance test scheme under different σ2 and σ3 conditions is designed correspondingly as Figure 2 shown. The method of using the equal-cycle curve cluster to determine the critical disturbance strength of the rock in the present invention is as follows: ten nodes with the same disturbance period are taken for each level of disturbance and the corresponding strain values are statistically analyzed. According to the stress and strain values corresponding to the same disturbance period, an equal-cycle curve cluster is plotted. The stress value corresponding to the obvious turning point where the curves in the equal-cycle curve cluster are separated is the critical disturbance strength σ cs of the rock, specifically asFigure 4 As shown in the figure. Table 1 summarizes the elastic modulus E0, Poisson's ratio v, peak strength σ of the rock under different true triaxial stress conditions p , disturbed failure stress σ d and disturbed critical strength σ cs .

[0110] In step S3, based on the peak strength σ of the rock obtained from the true triaxial static compression test p data, calculate the corresponding generalized shear stress q and mean stress p, plot the q-p scatter diagram, and use the modified Weibols-Cook strength criterion to fit and obtain the strength parameters a wc = 20.16, b wc = 1.74 and c wc = 1.93e -16 , as Figure 5 shown. Obtain the plastic yield function equation F and potential function G:

[0111]

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

[0113] In step S4, based on the disturbed failure stress σ of the rock obtained from the true triaxial multi-level disturbance test d data, calculate the corresponding generalized shear stress q and mean stress p, plot the q-p scatter diagram, and use the modified Weibols-Cook strength criterion to fit and obtain the strength parameters a wc = 28.486, b wc = 1.502 and c wc = 0.02462, as Figure 5 shown. Obtain the disturbed yield function F 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 algorithm flow of compiling the constitutive models constructed in step S3 and step S4 into a numerical program is as Figure 6 shown.

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

[0119]

[0120] Calculate the disturbance multiplier:

[0121]

[0122] Perform viscous correction on the stress:

[0123]

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

[0125]

[0126] Calculate the plastic multiplier:

[0127]

[0128] Perform plastic correction on the stress:

[0129]

[0130] Damage 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 tabulated in Table 2. And the key parameters β and ζ of rock plastic evolution under different stress conditions obtained by simulation are used to plot the three-dimensional scatter plot of the key parameters β and ζ under different stresses (σ2, σ3), as Figure 7 shown. Finally, the three-dimensional stress-induced brittle-ductile transition formulas β(σ2, σ3) and ζ(σ2, σ3) obtained by fitting are respectively:

[0135]

[0136]

[0137] where 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 tabulated in Table 3.

[0139] In step S8, a true triaxial static compression test of rock is simulated under different conditions of σ2 and σ3, and the corresponding parameters β and ζ are obtained through the three-dimensional stress-induced brittle-ductile transition formula for simulation. The characterization ability and prediction effect of the model proposed by the present invention on the static compression deformation evolution of rock are as Figure 8 and Figure 9 shown. A true triaxial multi-stage disturbed compression experiment is simulated under the same conditions of σ2 and σ3 but different disturbed stress conditions, and the characterization ability and prediction effect of the model proposed by the present invention on the disturbed deformation evolution of rock are as Figure 10 and Figure 11 shown.

[0140] Table 1 Disturbed failure stress σ of sandstone under true triaxial disturbed stress d and disturbed critical strength σ cs

[0141]

[0142] Table 2 Model parameters of the elastic-plastic part of the viscoelastic-plastic damage unified model

[0143]

[0144] Table 3 Model parameters of the dynamic disturbance part of the viscoelastic-plastic damage unified model

[0145]

[0146] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. Construction method of unified static-disturbance viscoelastic-plastic damage model under true three-dimensional stress, characterized in that Including the following steps: S1. Conduct true triaxial static compression tests under different σ2 and σ3 conditions, and obtain the basic mechanical parameters of the rock through the stress-strain curve. The basic mechanical parameters include: initial yield strength σ y , peak strength σ p , crack closure stress σ cc , initiation stress σ ci , residual strength σ r , Poisson's ratio υ, and elastic modulus E0; analyze the strength law of the rock under true triaxial static compression and the ductile-brittle evolution characteristics of the rock stress-strain curve; S2. The peak strength σ of the rock obtained from the static compression test c , design a true triaxial multi-level disturbance test scheme under the conditions of corresponding σ2 and σ3, use the equal cycle curve cluster to determine the disturbance critical strength of the rock, study the evolution characteristics of rock disturbance deformation, as well as the evolution laws 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 the analysis of true triaxial static tests, the modified Weibols-Cook strength criterion is used to characterize the strength law of rocks, and the function h p (γ p , ω) that describes the nonlinear behaviors of plastic hardening and damage softening of rock materials is introduced to establish the plastic yield function F. Based on the rock damage evolution law under true three-dimensional stress, the ductile-brittle damage evolution equation F d (Y d , ω) is constructed, which is specifically as follows: S3.

1. Based on the results of the true triaxial static test data in step S1, use the modified Weibols-Cook strength criterion to fit the peak strength of the rock under true triaxial static conditions: q = a wc + b wc p + c wc p 2 Where: p is the mean stress, q is the generalized shear stress, a wc , b wc and c wc are strength criterion parameters, σ1 is the maximum principal stress, σ2 is the intermediate principal stress, and σ3 is the minimum principal stress; S3.

2. Introduce a function h(<γ, ω>) that describes the non-linear behavior of plastic hardening and damage softening of rock materials based on the modified Weibols-Cook strength criterion, and establish the plastic yield function F and the plastic potential function G: p (γ p , ω), where h p (γ p , ω) is a function describing the non-linear behavior of plastic hardening and damage softening of rock materials, and are parameters controlling the characteristics of the plastic yield surface, and ω is the damage variable; S3.

3. Establish the damage evolution equation F reflecting the ductile-brittle evolution characteristics d (Y d , ω): F d (Y d , ω) = ω c th(B ω Y d ) - ω Among them, β controls the pre-peak plastic hardening non-linear behavior, ζ controls the damage rate, and describes the post-peak damage softening non-linear behavior characteristics of the rock; In order to control the ductility-brittle transition of the rock with the three-dimensional stress transformation, β and ζ are respectively replaced with the three-dimensional stress-induced ductility-brittle transition formulas β(σ2,σ3) and ζ(σ2,σ3) with σ2 and σ3 as internal variables. The specific expressions are as follows: Among them, a1, a2, a3, a4, and a5 are the coefficients of β(σ2,σ3), and b1, b2, b3, b4, and b5 are the coefficients of ζ(σ2,σ3); S4. Establish the disturbed yield function F with reference to the plastic yield function F in step S3 v and the disturbed potential function G v ; Based on the Perzyna overstress theory, establish the disturbance multiplier dλ v (N) related to the number of disturbances N; At the same time, according to the evolution characteristics of the rock disturbance strain, establish the disturbance parameter η v (N) and the rock disturbance accelerated deterioration factor D v (N), the method is as follows: S4.

1. Regard the disturbed yield surface as a lagged plastic yield surface and establish the disturbed yield function F v and the disturbed 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. Establish the irreversible strain equation of perturbation based on the perturbation potential function G v and the relationship between the number of perturbation times N and time t: N = ft S4.

3. Establish the expression of the perturbation multiplier dλ v (N): S4.

4. Based on the evolution characteristics of the deceleration stage and the constant velocity stage of the rock disturbance test, establish an expression for the disturbance parameter: η v (N) = η0[(A v + 1) - A v exp(-B v N)] Among them, A v and B v are parameters for controlling the evolution characteristics of the constant-speed stage and deceleration stage of rock disturbance strain; Analyze the evolution characteristics of the acceleration stage of rock disturbance. When the rock disturbance stress exceeds the disturbance critical strength σ cs , the rock enters the disturbance acceleration stage, and the rapid deterioration can be controlled by the deterioration factor D v (N) with the control parameter η v (N). When the rock disturbance stress does not exceed the critical stress σ L , D v (N) is ineffective and takes a value of zero: Among them, C v is a parameter for controlling the evolution characteristics of the accelerated stage of rock disturbance, D v (N) evolves between 0 and 0.999, Finally, the expression of the perturbation parameter η v (N) can be transformed into: η v (N) = (1 - D v (N))η0[(A v + 1) - A v exp(-B v N)] S5. Integrate the constitutive equations in steps S3 and 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 to establish a numerical simulation method for the model; S6. Through the numerical simulation method of the static-disturbance unified viscoelastic-plastic damage model established in step S5, simulate the true triaxial static compression test of the rock in step S1 to verify the elastic-plastic constitutive equation considering the true three-dimensional stress and damage effect established in step S3; at the same time, obtain the key parameters β and ζ of the rock plastic evolution under different three-dimensional stress conditions, and fit the coefficients of the three-dimensional stress-induced ductility-brittle transition formula; S7. By means of the model numerical simulation method established in step S5, simulate the true triaxial multi-level disturbance test of the rock in step S2, verify the viscoelastic constitutive equation established in step S4, and obtain the key parameters A v , B v and C v ; S8. Simulate the true triaxial static compression test of the rock and the true triaxial multi-stage disturbance compression test of the rock under different stress conditions to verify the prediction effect of the model.

2. The construction method of the 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 the static elastoplastic evolution of the numerical calculation of the model at the (k + 1)-th step, 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, then the plastic multiplier is calculated Damage increment dω k+1 and plastic strain increment dε p(k+1) , and the stress is plastically corrected: σ k+1 = σ k+1 - C(ω k+1 ) dε p(k+1) For the disturbed visco-elastoplastic evolution, if the stress level does not exceed the disturbed yield surface F v , the total strain is calculated elastically; if the stress level exceeds the disturbed yield surface F v , viscous correction is carried out; if the stress level does not exceed the plastic yield surface after viscous correction, the variables are updated; if the stress level exceeds the plastic yield surface after viscous correction, the stress is plastically corrected and then the variables are updated:

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

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