True triaxial stratified rock disturbance damage anisotropy model and numeralization method

Abstract

The invention provides a true triaxial stratified rock disturbance damage anisotropy model and a numeralization method, and the method comprises the following steps: S1, carrying out a true triaxial static test, and researching a peak intensity rule; s2, carrying out a true triaxial multistage disturbance test, and analyzing a disturbance critical intensity rule and anisotropic disturbance damage evolution characteristics; s3, establishing an anisotropic disturbance damage evolution equation; s4, constructing a stratified rock maximum failure constitutive equation under the true three-dimensional stress; s5, constructing a viscoelastic constitutive equation in which the true three-dimensional stress disturbance effect is introduced; s6, compiling the constitutive model established in S5 into a numeralization subprogram; s7, obtaining the maximum failure function parameter of the stratified rock in the peak state; s8, acquiring a three-dimensional disturbance yield function parameter of the stratified rock in a disturbance critical state; and S9, verifying the prediction effect and applicability of the model on the stratified rock disturbance deformation evolution. According to the invention, theoretical characterization of true three-dimensional stress, dynamic disturbance and spatial stratified coupling effect of stratified rock mass deformation and failure is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of rock mechanical properties and engineering research, in particular, a disturbed anisotropic damage model of layered rock under true triaxial and a numerical method thereof, which is suitable for the simulation and analysis of dynamic mechanical properties of layered rock under complex stress environment and the prediction and analysis of strength. BACKGROUND

[0002] With the rapid development of deep underground engineering, the environment of rock mass is increasingly complex, and its long-term stability faces unprecedented challenges. Deep rock mass is usually in an extreme environment of high ground stress, high temperature and high disturbance. The mechanical response of surrounding rock is no longer a single elastic behavior controlled by static load, but a viscoelastic-plastic and damage evolution process under the combined action of static load and dynamic disturbance. Especially in the construction process such as tunnel excavation, stress waves caused by artificial disturbance such as blasting and drilling will have a cumulative effect on the disturbed surrounding rock structure, and further affect the strength evolution, ductile-brittle transition behavior and failure mechanism of the surrounding rock.

[0003] Most of the existing rock constitutive models are based on two-dimensional simplification conditions, and it is difficult to characterize the stress redistribution effect under true three-dimensional principal stress. At the same time, the existing research on disturbance loading is simplified, and the disturbance is generally regarded as equivalent static load or additional disturbance energy, which is difficult to describe the coupling effect of disturbance frequency, amplitude, time and other factors on rock mass damage evolution. In addition, due to the existence of structural plane, layered rock shows significant transverse anisotropy under different loading paths. The elastic modulus, strength and damage evolution behavior under the coupling action of static force and disturbance change complexly with the spatial orientation of the bedding plane, and the traditional isotropic model or simple empirical relationship cannot accurately reflect this process. The lack of consideration of anisotropic damage evolution equation of layered rock under true three-dimensional complex stress path makes it difficult to describe the elastoplastic mechanical behavior of layered rock under true three-dimensional stress. Therefore, it is urgent to construct a mechanical model suitable for true three-dimensional stress path, which considers the anisotropic damage effect of disturbance and the viscoelastic-plastic evolution process

[0004] In view of the above shortcomings, the present application provides a disturbed anisotropic damage mechanical model of layered rock and a numerical method thereof, which can systematically reflect the anisotropic damage evolution characteristics and dynamic disturbance effect of layered rock in disturbance environment, and provide a reliable theoretical basis and numerical tool for the stability evaluation of surrounding rock in high-stress deep engineering. SUMMARY

[0005] The purpose of the present application is to provide a disturbed anisotropic damage model of layered rock under true triaxial and a numerical method thereof, which can reflect the mechanical properties of layered rock under true triaxial disturbance stress, and provide a reliable theoretical support for the failure disaster warning and long-term stability evaluation of surrounding rock in deep high-stress engineering.

[0006] In order to achieve the above technical purposes, the present application provides a true triaxial lower layered rock disturbance damage anisotropy model and a numerical method, and the steps thereof include:

[0007] S1, a true triaxial static test under different bedding dip angle α and bedding direction angle β is carried out to obtain the peak strength of the layered rock.

[0008] S2, according to the peak strength of the layered rock obtained by the static compression test, a true triaxial multi-stage disturbance test under different α and β is designed and carried out, and the isochronous curve cluster is used to determine the disturbance critical strength σ cs of the layered rock under the action of the true triaxial dynamic disturbance, and the disturbance deformation evolution characteristics of the rock, the evolution law of the disturbance critical strength σ cs and the disturbance failure stress σ d of the rock are studied; meanwhile, the elastic modulus under different damage degrees in each direction is calculated, and the anisotropic disturbance damage evolution characteristics of the layered rock under the action of the true triaxial dynamic disturbance are analyzed.

[0009] S3, the anisotropic disturbance damage variable of the layered rock under the action of the true triaxial dynamic disturbance is calculated according to the elastic modulus obtained by the test in step S2, the anisotropic disturbance damage characteristics are analyzed, and an anisotropic disturbance damage evolution equation representing the anisotropic disturbance damage evolution characteristics is established.

[0010] S4, a layered rock maximum failure constitutive equation under true three-dimensional stress is constructed: based on the true triaxial static test results, a transversely isotropic three-dimensional failure criterion is used to represent the strength law of the layered rock, and a layered rock maximum failure function F and a layered rock maximum failure potential function G are constructed.

[0011] S5, a viscoelastic constitutive equation introducing the disturbance effect of the true three-dimensional stress is constructed: referring to the maximum failure function F in step S4, a layered rock three-dimensional disturbance yield function F v and a layered rock three-dimensional disturbance potential function G v are established; based on the Perzyna over-stress theory, a disturbance multiplier dλ v is established; meanwhile, according to the evolution characteristics of the rock disturbance strain, a disturbance parameter k v (t) related to the disturbance time t and a rock disturbance acceleration control equation V d (t) are established.

[0012] S6, the constitutive equations in steps S3 and S4 are coupled with the anisotropic disturbance damage evolution equation in step S2 to construct a complete layered rock disturbance damage viscoelastic plastic mechanics model; the model is compiled into a user-defined material subroutine of the finite element software to establish a model numerical simulation method.

[0013] S7, simulate the true triaxial static compression test of the rock in step S1 by the numerical simulation method of the model established in step S6, verify the maximum failure constitutive equation of the layered rock established in step S3, and obtain the plastic part parameters of the model and the maximum failure function parameters of the layered rock in the peak state.

[0014] S8, simulate the true triaxial multi-stage disturbance test of the rock in step S2 by the numerical simulation method of the model established in step S6, verify the viscoelastic constitutive equation established in step S5, and obtain the key parameters V of the disturbance strain evolution of the rock under different α and β conditions. a 、V b 、V c and the three-dimensional disturbance yield function parameters of the layered rock in the disturbance critical state.

[0015] S9, simulate the true triaxial multi-stage disturbance compression test under different α and β conditions, and verify the prediction effect and applicability of the model to the disturbance deformation evolution of the layered rock.

[0016] In step S1, the true triaxial static compression peak strength σ p of the rock under different α and β conditions is counted.

[0017] In step S2, based on the peak strength σ p , 0.400σ p , 0.600σ p , 0.700σ p , 0.800σ p , 0.850σ p , 0.900σ p , 0.9250σ p , 0.950σ p , 0.9750σ p , σ p , the stress level is increased by 0.025σ p at each stage in the later stage of the test until the sample is destroyed. After σ1 is loaded to the specified stress level, the sinusoidal stress wave disturbance with a frequency of 0.5 Hz and an amplitude of 1 MPa is carried out, each disturbance has 100 cycles, and the disturbance is carried out step by step until the rock is destroyed; ten characteristic nodes with the same disturbance time are selected under each disturbance condition, and the corresponding strain response data are counted; based on the stress-strain correspondence under the same disturbance time, a series of isochronal curve clusters are drawn, the critical point corresponding to the obvious turning point of the curve in the isochronal curve cluster is determined as the disturbance critical strength σ cs .

[0018] The method for establishing the anisotropic damage evolution equation representing the anisotropic damage evolution characteristics in step S3 is as follows:

[0019] S3.1 Based on the disturbance damage evolution analysis of layered rocks under true triaxial dynamic disturbance in step S2, establish a disturbance damage evolution formula that varies with the disturbance stress level parameter:

[0020] (1)

[0021] (2)

[0022] in, The damage variable is in the direction of maximum principal stress. Let λ be the damage variable in the direction of minimum principal stress, λ be the percentage of peak strength of layered rock at each loading level, and λ0 be the percentage of peak strength of layered rock corresponding to the initial stress level. 1 c , λ 1 a , λ 3 a , λ 3 c is the smoothing parameter for the perturbation damage evolution formula.

[0023] S3.2. Based on the spatial relationship between damage variables in the principal stress direction and structural damage variables perpendicular to and parallel to the bedding planes, an anisotropic perturbation damage evolution equation is established as the perturbation stress level varies:

[0024] (3)

[0025] in, Elastic modulus corresponding to the vertical layering plane The damage evolution equation, Elastic modulus corresponding to parallel layered planes The damage evolution equation is as follows: When the disturbance stress level does not reach the damage initiation threshold, the rock remains in an undamaged state (damage variable is 0); once the stress exceeds the threshold, the rock enters the damage evolution stage, and the damage variable begins to accumulate.

[0026] The method for establishing the constitutive equation for maximum failure of layered rocks considering true three-dimensional stress in step S4 is as follows:

[0027] S4.1 Based on the static test data analysis in step S1, the strength law of layered rocks is characterized by the transverse isotropic three-dimensional failure criterion, and the maximum failure function F and the maximum failure potential function G of layered rocks are constructed:

[0028] (4)

[0029] (5)

[0030] (6)

[0031] where, and are the maximum principal stress, the intermediate principal stress, and the minimum principal stress, respectively, p is the mean stress, and q is the generalized shear stress, is the internal friction angle, is the anisotropic strength characteristic function, and θ is the stress Lode angle, which is in the range of The specific expression is as follows:

[0032] (7) where J3 is the third invariant,

[0033] is the plastic hardening function with the equivalent shear strain as the internal variable:

[0034] (8)

[0035] (9)

[0036] where, controls the initial yield threshold, controls the final yield threshold; characterizes the pre-peak nonlinear deformation characteristics, controls the post-peak nonlinear evolution behavior, e p ij is the plastic deviatoric strain increment.

[0037] The maximum failure potential function G of layered rock is in the same form as the maximum failure function F of layered rock:

[0038] (10)

[0039] is the anisotropic strength characteristic function:

[0040] (11)

[0041] (12)

[0042] S4.3, Plastic multiplier dλ is calculated from the plastic potential function p :

[0043] According to Hooke’s law, the expression of the stress increment tensor is:

[0044] (13)

[0045] In addition, the plastic increment of the rock plastic stage The plastic flow rule can be determined according to the plastic flow rule:

[0046] (14)

[0047] (15)

[0048] (16)

[0049] Wherein, dλ p is a plastic multiplier, which is non-negative. s is a softness matrix, and δ is a unit tensor, is a material parameter, is a characteristic length, and the transversely isotropic softness matrix When the rock is in a plastic stress state, the stress will not pass through the yield surface, but will fall on the yield surface (F = 0), that is, the plastic consistency condition dF = 0 is satisfied:

[0050] (17)

[0051] The plastic multiplier dλ p can be derived by bringing (12) and (13) into (14):

[0052] (18)

[0053] The method for constructing the viscoelastic constitutive equation in the step S5 is:

[0054] S5.1, the disturbed yield surface can be regarded as a plastic yield surface with hysteresis, and a three-dimensional disturbed yield function F v of layered rock and a three-dimensional disturbed potential function G v of layered rock are established:

[0055] (19)

[0056] (20)

[0057] is a plastic hardening function taking the equivalent shear strain as an internal variable: (21)

[0058] Wherein, , and The characteristic of the disturbed yield surface can take the same value as the plastic yield surface, Let be the anisotropic strength characteristic function of the rock under the perturbation critical state. Controlling the nonlinear evolution behavior after the peak.

[0059] S5.2 Establish the equation for irreversible strain due to disturbance:

[0060] (twenty two)

[0061] S4.3. Based on Perzyna overstress theory, establish the expression for the perturbation multiplier:

[0062] (twenty three)

[0063] Finally, the irreversible strain of the disturbance is written as:

[0064] (twenty four)

[0065] S5.3. Based on the evolution characteristics of the deceleration and isokinetic phases of the rock disturbance test, establish the disturbance parameter equations:

[0066] (25)

[0067] in, Control the isochronous evolution behavior of the disturbance. Controlling the deceleration evolution behavior of disturbances. The frequency is the disturbance frequency.

[0068] S5.4 Analysis of the deformation evolution characteristics of bedding sandstone under dynamic disturbance shows that when the disturbance stress exceeds the critical disturbance strength σ cs Subsequently, the disturbance strain accelerates, and rock cracks penetrate more rapidly; to characterize this unstable failure feature, the degradation parameter can be... Introduction When the disturbance stress level does not exceed σ cs hour, The value is zero when the disturbance stress level exceeds σ. cs hour, Rapidly increasing, the disturbance strain develops at an accelerated pace:

[0069] (26)

[0070] in, control The rate of evolution, It evolves between 0 and 0.999.

[0071] The method for integrating the constitutive equations from steps S3 and S4 and the anisotropic damage evolution equation from step S2 into a viscoelastic-plastic mechanical model of layered rock perturbation damage in step S6, and compiling it into a numerical subroutine, is as follows:

[0072] S6.1. Divide the total strain into elastic strain, plastic strain, and irreversible disturbance strain, and first perform elastic prediction:

[0073] (27)

[0074] (28)

[0075] S5.2 Apply elastic predicted stress and calculate the perturbation yield function under this stress state. If the stress state does not exceed the perturbation yield surface If the stress state exceeds the perturbation yield surface, then the variable is output directly; Then calculate the irreversible strain increment of the disturbance. To correct the stress:

[0076] (29)

[0077] S5.3 Calculate the plastic yield function based on the corrected stress state. .if Then, the stress is plastically adjusted. Correction. ;if Then the variable will be output. In step S9, the method for simulating true triaxial multi-stage perturbation experiments under different α and β conditions to verify the model's predictive effect and applicability for the perturbation deformation evolution of layered rocks is as follows: Based on the model parameters obtained in step S6 under different dip angle conditions, simulate true triaxial multi-stage perturbation experiments with a dip angle of 45° and dip angles of 30°, 45°, and 75°. Based on the model parameters obtained in step S6 under different directional angle conditions, simulate true triaxial multi-stage perturbation experiments with a dip angle of 30° and directional angles of 15°, 45°, and 75°. Compare the deformation curves of the simulation and the experiment to verify the model's predictive effect on the dynamic mechanical behavior of layered rocks.

[0078] The beneficial effects of this invention are as follows:

[0079] 1. The anisotropic damage evolution equation established in this invention, which varies with the level of disturbance stress, can characterize the anisotropic damage evolution characteristics of layered rocks under true triaxial static-disturbance coupling.

[0080] 2. The model of this invention can characterize the true three-dimensional stress, dynamic disturbance, and spatial layered coupling effect of layered rock failure.

[0081] 3、The rock can be well exhibited in three-dimensional stress induced dynamic disturbance degradation effect, and the evolution characteristics of three stages of attenuation stage, constant speed stage and acceleration stage in the disturbance deformation process of rock under true triaxial stress can be characterized completely. BRIEF DESCRIPTION OF DRAWINGS

[0082] Figure 1 It is a flowchart for each step;

[0083] Figure 2 It is a true triaxial multi-stage disturbance test scheme diagram;

[0084] Figure 3 It is a disturbance critical strength definition diagram;

[0085] Figure 4 It is an elastic modulus calculation schematic diagram under different damage in each direction;

[0086] Figure 5 It is a fitting diagram of disturbance damage in each direction under different bedding direction angles;

[0087] Figure 6 It is a fitting diagram of disturbance damage in each direction under different bedding inclination direction angles;

[0088] Figure 7 It is a bedding rock maximum damage function parameter fitting diagram;

[0089] Figure 8 It is a bedding rock three-dimensional disturbance yield function parameter fitting diagram;

[0090] Figure 9 Algorithm flowchart;

[0091] Figure 10 It is a comparison diagram of disturbance experimental results and simulation results under different bedding direction angles;

[0092] Figure 11 It is a comparison diagram of disturbance experimental results and simulation results under different bedding inclination angles; DETAILED DESCRIPTION

[0093] The specific embodiments of the present application will be described below in conjunction with the accompanying drawings, but the present application is not limited to the scope of the specific embodiments. It should be noted that the creation based on the present application or the creation dependent on the present application is within the protection scope of the present application.

[0094] Embodiment:

[0095] This embodiment provides to construct and verify the accuracy and rationality of the layered rock disturbance damage viscoelastic plastic mechanics model and numerical method by taking layered sandstone as a rock sample.

[0096] Reference Figure 1 ,Figure 1 A flow chart of each step is shown as Figure 1 The method comprises steps S1 to S10.

[0097] In step S1, true triaxial static compression tests are performed on the layered sandstone under different α, β conditions to determine the peak strength σ p .

[0098] In step S2, according to the rock strength obtained from the static compression test, a true triaxial multi-stage disturbance test scheme under different α, β conditions is designed as shown in Figure 2 The isochronal curve cluster method adopted by the present application to determine the disturbance critical strength of the layered rock is as follows: ten nodes of the same disturbance period are taken for each disturbance stage, and the corresponding strain values are counted; according to the stress and strain values corresponding to the same disturbance period, an isochronal curve cluster is drawn, and the stress value corresponding to the turning point at which the curves in the isochronal curve cluster are obviously separated is the disturbance critical strength σ cs of the rock, as shown in Figure 3 Table 1 lists the peak strength σ p , the disturbance failure stress σ d and the disturbance critical strength σ cs of the rock under different true triaxial stress conditions. The damage variables at each stage are calculated as shown in Figure 4

[0099] In step S3, a disturbance damage evolution formula varying with the disturbance stress level is established:

[0100]

[0101] Based on the true triaxial multi-stage disturbance test results under different α, β conditions, the parameters of the disturbance damage evolution formula obtained by fitting are shown in Figure 5 , Figure 6 and are listed in Tables 2 and 3.

[0102] Further, the anisotropic damage evolution equation is:

[0103]

[0104] In step S4, the parameters of the maximum failure function F of the layered rock are fitted based on the peak strength σ p data of the rock obtained from the true triaxial static compression test. Under different bedding direction angle conditions, they are: , , , and ; and under different bedding inclination angle conditions, they are: , , ,​ and , the fitting results are shown in Figure 7 .

[0105] Under the condition of different bedding dip angles, the obtained maximum failure function F and maximum failure potential function G of the layered rock are:

[0106]

[0107]

[0108]

[0109] Under the condition of different bedding dip angles, the obtained maximum failure function F and maximum failure potential function G of the layered rock are:

[0110]

[0111]

[0112]

[0113] In step S5, the critical disturbance strength σ cs of the rock obtained according to the true triaxial multi-stage disturbance test is fitted to obtain the three-dimensional disturbance yield function F v of the layered rock, and the fitting results are shown in , , , and under the condition of different bedding dip angles, and the fitting results are shown in , , , and under the condition of different bedding direction angles. Figure 8

[0114] Under the condition of different bedding dip angles, the obtained three-dimensional disturbance yield function F v and three-dimensional disturbance potential function G v of the layered rock are:

[0115]

[0116]

[0117]

[0118] Under the condition of different bedding direction angles, the obtained three-dimensional disturbance yield function F v and three-dimensional disturbance potential function G v ​For:

[0119]

[0120]

[0121]

[0122] In step S6, the constitutive equation in step S3 and step S4 and the anisotropic damage evolution equation in step S2 are integrated into a layered rock disturbance damage viscoelastic plastic mechanics model, and the algorithm flow of the numerical subprogram is compiled as shown in Figure 9

[0123] When the stress level exceeds the disturbance yield surface:

[0124]

[0125] The disturbance multiplier is calculated:

[0126]

[0127] The stress is viscously corrected:

[0128]

[0129] When the stress level exceeds the plastic yield surface:

[0130]

[0131] The plastic multiplier is calculated:

[0132]

[0133] The stress is plasticity corrected:

[0134]

[0135] In step S7, the maximum damage function parameters of the layered rock under different alpha, beta conditions obtained by simulating the true triaxial static test are counted in Table 4.

[0136] In step S8, the three-dimensional disturbance yield function parameters of the layered rock obtained by simulating the true triaxial multi-level disturbance test are counted in Table 5.

[0137] In step S9, the true triaxial multi-level disturbance test under different alpha, beta conditions is simulated, and the characterization ability and prediction effect of the model proposed in the application on the disturbance deformation evolution of the rock are as shown in Figure 10 and Figure 11 ​​

[0138] Finally, it is to be understood that the above description is intended to be illustrative and not restrictive. Many other embodiments will be apparent to those of skill in the art upon reading the above description. The scope of the application should, therefore, be determined not with reference to the above description, but instead with reference to the appended claims, along with their full scope of equivalents.

Claims

1. A true triaxial anisotropic model and numerical method for disturbance damage in layered rocks, characterized in that, Includes the following steps: S1. Conduct true triaxial static tests under different bedding dip angles α and bedding direction angles β to obtain the peak strength of layered rocks; S2. Based on the peak strength of the layered rock obtained from the static compression test, a true triaxial multi-stage disturbance test under different α and β conditions was designed and carried out. The critical disturbance strength σ of the layered rock under true triaxial dynamic disturbance was determined by using a cluster of isochronous curves. cs The study investigated the evolution characteristics of rock disturbance deformation and the critical strength σ of rock disturbance. cs and disturbance damage stress σ d The evolution law; at the same time, the elastic modulus under different damage degrees in each direction is calculated, and the anisotropic disturbance damage evolution characteristics of layered rocks under true triaxial dynamic disturbance are analyzed. S3. Calculate the anisotropic disturbance damage variables of layered rocks under true triaxial dynamic disturbance based on the elastic modulus obtained from the experiment in step S2, analyze the anisotropic disturbance damage characteristics, and establish an anisotropic disturbance damage evolution equation that characterizes the anisotropic disturbance damage evolution characteristics. S4. Constructing the constitutive equation for maximum failure of layered rock under true three-dimensional stress: Based on the results of true triaxial static test, the strength law of layered rock is characterized by transversely isotropic three-dimensional failure criterion, and the maximum failure function F and the maximum failure potential function G of layered rock are constructed. S5. Constructing a viscoelastic constitutive equation incorporating true three-dimensional stress perturbation effects: Referring to the maximum failure function F in step S4, establish the three-dimensional perturbation yield function F of layered rock. v and the three-dimensional perturbation potential function G of layered rocks v Based on Perzyna overstress theory, a perturbation multiplier dλ is established. v Simultaneously, based on the evolution characteristics of rock disturbance strain, a disturbance parameter k related to the disturbance time t is established. v (t) and the rock disturbance acceleration control equation V d (t); S6. Couple the constitutive equations in steps S4 and S5 with the anisotropic perturbation damage evolution equation in step S3 to construct a complete viscoelastic-plastic mechanical model of perturbation damage in layered rock; compile the model into a user-defined material subroutine of the finite element software and establish a numerical simulation method for the model. S7. Using the numerical simulation method established in step S6, simulate the true triaxial static compression test of rock in step S1, verify the constitutive equation for maximum failure of layered rock established in step S3, and obtain the plastic part parameters of the model and the maximum failure function parameters of layered rock under peak state. S8. Using the numerical simulation method established in step S6, simulate the true triaxial multi-level perturbation test of the rock in step S2 to verify the viscoelastic constitutive equation established in step S5, and obtain the key parameter V of rock perturbation strain evolution under different α and β conditions. a V b V c And the three-dimensional perturbation yield function parameters of layered rocks under perturbation critical state; S9. Simulate true triaxial multi-stage perturbation compression experiments under different α and β conditions to verify the model's predictive effect and applicability for the perturbation deformation evolution of layered rocks.

2. The viscoelastic-plastic mechanical model and numerical method for layered rock disturbance damage according to claim 1, characterized in that, In step S3, the method for establishing the anisotropic perturbation damage evolution equation characterizing the anisotropic perturbation damage evolution features is as follows: S3.1 Based on the disturbance damage evolution analysis of layered rocks under true triaxial dynamic disturbance in step S2, establish a disturbance damage evolution formula that varies with the disturbance stress level parameter: in, The damage variable is the one in the direction of maximum principal stress. Let λ be the damage variable in the direction of minimum principal stress, λ be the percentage of peak strength of layered rock at each loading level, and λ0 be the percentage of peak strength of layered rock corresponding to the initial stress level. 1 c , λ 1 a , λ 3 a , λ 3 c For the smoothing parameter of the disturbance damage evolution formula; S3.

2. Based on the spatial relationship between damage variables in the principal stress direction and structural damage variables perpendicular to and parallel to the bedding planes, an anisotropic perturbation damage evolution equation is established as the perturbation stress level varies: in, Elastic modulus corresponding to the vertical layering plane The damage evolution equation, Elastic modulus corresponding to parallel layered planes The damage evolution equation states that when the disturbance stress level does not reach the damage initiation threshold, the rock remains in an undamaged state, i.e., the damage variable is 0; when the stress exceeds the threshold, the rock enters the damage evolution stage, and the damage variable begins to accumulate.

3. The viscoelastic-plastic mechanical model and numerical method for layered rock disturbance damage according to claim 1, characterized in that, The method for constructing the maximum failure function F and the maximum failure potential function G of layered rock in step S4 is as follows: S4.1 Based on the static test data analysis in step S1, the strength law of layered rocks is characterized by the transverse isotropic three-dimensional failure criterion, and the maximum failure function F and the maximum failure potential function G of layered rocks are constructed: in, and Here, σ1, σ2, and σ3 are the strength parameters, representing the maximum principal stress, intermediate principal stress, and minimum principal stress, respectively; p is the mean stress; and q is the generalized shear stress. It is the internal friction angle. Let θ be the anisotropic strength characteristic function, and let θ be the Lode angle of stress, with a range of values ​​of 1000. The specific expression is as follows: Among them, J3 is the third invariant. Therefore, equivalent shear strain Plastic hardening function as an internal variable: in, Control the initial yield threshold, Control the final yield threshold; Characterizes the nonlinear deformation features before the peak. Controlling the post-peak nonlinear evolution behavior, e p ij This is the plastic deviatoric strain increment; S4.2 The maximum failure potential function G of layered rock takes the same form as the maximum failure function F of layered rock: Here are the anisotropic intensity characteristic functions: For material parameters, The characteristic length; S4.3 Calculation of the plastic multiplier dλ based on the plastic potential function p : According to Hooke's law, the expression for the stress increment tensor is: Plastic increment during the plastic stage of rock Determined according to the plastic flow law: Where, dλ p It is the plasticity multiplier, which is non-negative. s is the compliance matrix, and δ is the unit tensor. When the rock is in a state of plastic stress, the stress will not pass through the yield surface, but will fall on the yield surface. F = 0, that is, it satisfies the plasticity consistency condition dF = 0. Will and Substitution The plastic multiplier dλ is derived from this. p : 。 4. The viscoelastic-plastic mechanical model and numerical method for layered rock disturbance damage according to claim 1, characterized in that, In step S5, the three-dimensional perturbation yield function F of the layered rock is... v and the three-dimensional perturbation potential function G of layered rocks v , perturbation multiplier dλ v The disturbance parameter k related to the disturbance time t v (t) and the rock disturbance acceleration control equation V d The construction method of (t) is as follows: S5.1 The perturbation yield surface is a hysteretic plastic yield surface. A three-dimensional perturbation yield function F for layered rocks is established. v and the three-dimensional perturbation potential function G of layered rocks v : in, , and The parameters for controlling the perturbation yield surface to be the same as those for the plastic yield surface are controlled. The anisotropic strength characteristic function of the rock under the perturbation critical state; S5.2 Establish the equation for irreversible strain due to disturbance: S5.

3. Based on Perzyna overstress theory, establish the expression for the perturbation multiplier: Where f is the disturbance frequency, and finally, the irreversible strain of the disturbance is written as: S5.

4. Based on the evolution characteristics of the deceleration and isokinetic phases of the rock disturbance test, establish the disturbance parameter equations: in, Control the isochronous evolution behavior of disturbances. Controlling the deceleration evolution behavior of disturbances; S5.5 Analyze the deformation evolution characteristics of bedding sandstone under dynamic disturbance. When the disturbance stress exceeds the critical disturbance strength σ cs Subsequently, the disturbance strain accelerates, and rock cracks penetrate more rapidly; to characterize this instability and failure feature, the degradation parameter is... Introduction When the disturbance stress level does not exceed σ cs hour, The value is zero when the disturbance stress level exceeds σ. cs hour, Rapidly increasing, the disturbance strain develops at an accelerated pace: in, control The rate of evolution, It evolves between 0 and 0.

999.

5. The true triaxial layered rock disturbance damage anisotropy model and numerical method according to claim 1, characterized in that, In step S6, the numerical method for the anisotropic model of disturbance damage in layered rocks under true triaxial conditions is as follows: S6.

1. Divide the total strain into elastic strain, plastic strain, and irreversible disturbance strain, and first perform elastic prediction: S6.2 Apply elastic predicted stress and calculate the perturbation yield function under this stress state. If the stress state does not exceed the perturbation yield surface If so, then output the variable directly; If the stress state exceeds the perturbation yield surface Then calculate the irreversible strain increment of the disturbance. To correct the stress: S6.3 Calculate the plastic yield function based on the corrected stress state. ,if Then, the stress is plastically corrected. ;if Then the variable will be output.

6. The true triaxial layered rock disturbance damage anisotropy model and numerical method according to claim 1, characterized in that, In step S9, the method for simulating true triaxial multi-stage perturbation experiments under different α and β conditions to verify the model's predictive effect and applicability for the perturbation deformation evolution of layered rocks is as follows: Based on the model parameters obtained in step S6 under different dip angle conditions, simulate true triaxial multi-stage perturbation experiments with a dip angle of 45° and dip angles of 30°, 45°, and 75°. Based on the model parameters obtained in step S6 under different directional angle conditions, simulate true triaxial multi-stage perturbation experiments with a dip angle of 30° and directional angles of 15°, 45°, and 75°. Compare the deformation curves of the simulation and the experiment to verify the model's predictive effect on the dynamic mechanical behavior of layered rocks.

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