Rock mass structural plane dynamic disturbance failure criterion under true three-dimensional stress

Abstract

The invention discloses a rock mass structural plane dynamic disturbance failure criterion under true three-dimensional stress, and the construction process comprises the following steps: S1, carrying out a true triaxial disturbance shear test, and determining rock mass structural plane disturbance critical shear strength tau c; s2, constructing a disturbance critical shear strength function model G1 under different amplitudes A; s3, constructing a disturbance critical shear strength function model G2 under the action of different frequencies f; s4, constructing a disturbance critical shear strength function model G3 under different normal stresses sigma n; s5, constructing a disturbance critical shear strength function model G4 under different lateral stresses sigma p; s6, constructing a disturbance critical shear strength function model G5 in a three-dimensional stress state, and determining a disturbance critical shear strength function envelope surface form; and S7, carrying out a true triaxial disturbance shear test under the test condition different from that in the S1, verifying and perfecting the rock mass structural plane disturbance critical shear strength function model under the three-dimensional stress state, and constructing a rock mass structural plane dynamic disturbance failure criterion under true three-dimensional stress.

Description

Technical Field

[0001] The invention relates to the field of rock mechanical properties and engineering research, and in particular to a dynamic disturbance failure criterion of a rock structure surface under true three-dimensional stress. Background Art

[0002] The rock structure plays a key role in the disaster type and stability of rock engineering after excavation, especially in deep buried tunnel engineering. The rock mass of the surrounding rock structure surface is in a true three-dimensional ground stress state and is affected by three-dimensional stresses: shear stress, normal stress, and lateral stress. Since strong stress waves are generated by blasting, mechanical drilling, or rock bursts and fractures in nearby areas during tunnel construction, the strong stress waves quickly decay into low-amplitude and low-frequency disturbance waves during the propagation of the surrounding rock. This disturbance wave can still cause a large number of microcracks in the damaged layered rock to expand and penetrate, causing damage. The damage extends along the layer, resulting in the expansion of the surrounding rock damage area and even disasters. Traditional rock structure surface criterion, such as the Mohr-Coulomb strength criterion, does not consider the influence of the amplitude and frequency of lateral stress and dynamic disturbance stress. The triggering conditions of shear failure of rock structure surface under the three-dimensional stress state predicted by it are not fully adapted to deep rock engineering, resulting in inaccurate prediction of disasters on the surrounding rock structure surface. Therefore, it is necessary to construct a dynamic disturbance failure criterion for rock structure surface under true three-dimensional stress as a criterion for dynamic disturbance shear failure of rock structure surface under true three-dimensional stress conditions. Summary of the invention

[0003] The purpose of the present invention is to provide a dynamic disturbance failure criterion for rock structure surface under true three-dimensional stress, which serves as a criterion for shear failure of rock structure surface under true three-dimensional stress level, and provides a theoretical basis for predicting shear failure disasters of rock structures containing structure surfaces in high-stress deep engineering.

[0004] In order to achieve the above technical objectives, the present invention provides a dynamic disturbance failure criterion for rock mass structural surface under true three-dimensional stress, which includes:

[0005] S1. Carry out true triaxial perturbation shear test to determine the normal stress σ n and different lateral stresses σ p , Critical shear strength τ of rock mass structural surface disturbance under different amplitudes A and different frequencies f c ;

[0006] S2. Obtain the same normal stress σ under true triaxial n , lateral stress σ p , frequency f and critical shear strength τ of rock mass structural surface disturbance under different amplitudes A c According to the changing law, the critical shear strength function model G1(A) of rock mass structural surface disturbance is constructed;

[0007] S3. Obtain the same normal stress σ under true triaxial n, lateral stress σ p , amplitude A and critical shear strength τ of rock mass structural surface disturbance under different frequencies f c According to the changing law, the critical shear strength function model G2(f) of rock mass structural surface disturbance is constructed;

[0008] S4. Obtain the same lateral stress σ under true triaxial p , amplitude A, frequency f and different normal stress σ n Critical shear strength τ of rock mass structural surface disturbance under c The critical shear strength function model G3(σ n );

[0009] S5. Obtain the same normal stress σ under true triaxial n , amplitude A, frequency f and different lateral stress σ p Critical shear strength τ of rock mass structural surface disturbance under c The critical shear strength function model G4(σ p );

[0010] S6, based on steps S2 and S3, S4, S5, construct the critical shear strength function model G5 (σ n ,σ p ,A,f), determine the envelope shape of the critical shear strength function of the rock mass structural surface disturbance;

[0011] S7, develop normal stress σ different from S1 n , lateral stress σ p The true triaxial perturbation shear test of rock mass structure surface under the combination of amplitude A and frequency f is carried out to obtain the corresponding perturbation critical shear strength of rock mass structure surface, and verify and improve the perturbation critical shear strength function model G5(σ n ,σ p ,A,f), characterized by constructing the dynamic disturbance failure criterion G(σ n ,σ p ,A,f) is constructed as follows:

[0012] S7.1. Carry out the normal stress σ different from that in S1 n , lateral stress σ p , amplitude A and frequency f, and obtain the corresponding rock mass structural surface disturbance critical shear strength test value τ c ;

[0013] S7.2. Replace the normal stress σ in S7.1 with the normal stress σ in S1. n , lateral stress σ p, amplitude A and frequency f are substituted into the critical shear strength function model G5(σ n ,σ p ,A,f), and obtain the predicted value τ of the critical shear strength of the rock mass structural surface disturbance g ;

[0014] S7.3. Calculation of the critical shear strength test value τ of the rock mass structural surface disturbance c and the predicted value τ g The root mean square of the rock mass structure surface dynamic disturbance failure criterion G(σ n ,σ p ,A,f): in, is the internal friction angle, σ ρ is the lateral stress corresponding to the maximum shear stress of the rock mass structural surface, K is the lateral stress equal to the critical shear strength of the disturbance when the lateral stress is 0, and P, B, C, and D are model parameters.

[0015] In step S1, different normal stresses σ n and different lateral stresses σ p , true triaxial perturbation shear test under different amplitudes A and different frequencies f, and obtain the corresponding perturbation critical shear strength τ c The method is:

[0016] S1.1. Test data of dynamic disturbance shear loading failure of rock mass structural surface under different test conditions obtained through true triaxial disturbance shear test;

[0017] S1.2. Take the shear stress and strain at each level under the condition of equal number of cycles and plot τ-ε τ Relationship diagram;

[0018] S1.3. The stress at the inflection point where the slope of the curve drops suddenly is defined as the perturbation critical shear strength τ c .

[0019] In step S2, the same normal stress σ under true triaxial conditions is obtained. n , lateral stress σ p , frequency f and critical shear strength τ of rock mass structural surface disturbance under different amplitudes A c The method of constructing the critical shear strength function model G1(A) of rock mass structural surface disturbance is as follows: S2.1. Construct the normal stress σ under the same three-dimensional stress state based on the perturbation critical shear strength obtained in step S1 n , lateral stress σ p, frequency f and critical shear strength τ of rock mass structural surface disturbance under different amplitudes A c Laws of change; S2.2. Construct the critical shear strength function model G1(A) of rock mass structural surface disturbance: G1(A)=a+b·A α (1) Among them, a, b, and α are model parameters.

[0020] In step S3, the same normal stress σ under true triaxial pressure is obtained. n , lateral stress σ p , amplitude A and critical shear strength τ of rock mass structural surface disturbance under different frequencies f c The method of constructing the critical shear strength function model G2(f) of rock mass structural surface disturbance is as follows:

[0021] S3.1. Construct the normal stress σ under the same three-dimensional stress state based on the perturbation critical shear strength obtained in step S1 n , lateral stress σ p , amplitude A and critical shear strength τ of rock mass structural surface disturbance under different frequencies f c Laws of change;

[0022] S3.2. Construct the critical shear strength function model G2(f) of rock mass structural surface disturbance: G2(f)=c+lg(h·f d ) (2) Among them, c, d, and h are model parameters.

[0023] In step S4, the same lateral stress σ under true triaxial pressure is obtained. p , amplitude A, frequency f and different normal stress σ n Critical shear strength τ of rock mass structural surface disturbance under c The critical shear strength function model G3(σ n ) is:

[0024] S4.1. Construct the same lateral stress σ under the three-dimensional stress state based on the perturbation critical shear strength obtained in step S1 p , amplitude A, frequency f and different normal stress σ n Critical shear strength τ of rock mass structural surface disturbance under c Laws of change;

[0025] S4.2. Construct the critical shear strength function model G3(σ n ): Among them, i is the model parameter, is the angle of internal friction.

[0026] In step S5, the same normal stress σ under true triaxial pressure is obtained. n , amplitude A, frequency f and different lateral stress σ p Critical shear strength τ of rock mass structural surface disturbance under c The critical shear strength function model G4(σ p ) is:

[0027] S5.1. Construct the same normal stress σ under the three-dimensional stress state based on the perturbation critical shear strength obtained in step S1. n , amplitude A, frequency f and different lateral stress σ p Critical shear strength τ of rock mass structural surface disturbance under c Laws of change;

[0028] S5.2. Construct the critical shear strength function model G4(σ p ): Among them, l and r are model parameters, σ ρ is the lateral stress corresponding to the maximum rock shear stress, and K is the lateral stress with the same strength as the critical shear strength of the disturbance when the lateral stress is 0.

[0029] In step S6, a critical shear strength function model G5 (σ) of the rock mass structural surface disturbance under three-dimensional stress state is constructed based on steps S2, S3, S4, and S5. n ,σ p ,A,f), the method to determine the envelope shape of the critical shear strength function of the rock mass structural surface disturbance is:

[0030] S6.1. Based on the shear peak strength law of rock mass structural surface under different normal stresses, different lateral stresses, different amplitudes, and different frequencies in three-dimensional stress states, the critical shear strength τ of rock mass structural surface disturbance under three-dimensional stress states is constructed. c Laws of change;

[0031] S6.2. Construct the critical shear strength function model G5(σ n ,σ p ,A,f): Among them, b, d, h, and r are model parameters, and n is the cohesion;

[0032] S6.3. Based on the constructed rock mass structural surface disturbance critical shear strength function model, determine the envelope surface shape of the rock mass structural surface disturbance critical shear strength function.

[0033] In step S7, a normal stress σ different from that in step S1 is carried out. n , lateral stress σ p The true triaxial perturbation shear test of rock mass structure surface under the combination of amplitude A and frequency f is carried out to obtain the corresponding perturbation critical shear strength of rock mass structure surface, and verify and improve the perturbation critical shear strength function model G5(σ n ,σ p ,A,f), characterized by constructing the dynamic disturbance failure criterion G(σ n ,σ p ,A,f) is constructed as follows:

[0034] S7.1. Carry out the normal stress σ different from that in S1 n , lateral stress σ p , amplitude A and frequency f, and obtain the corresponding rock mass structural surface disturbance critical shear strength test value τ c ;

[0035] S7.2. Replace the normal stress σ in S7.1 with the normal stress σ in S1. n , lateral stress σ p , amplitude A and frequency f are substituted into the critical shear strength function model G5(σ n ,σ p ,A,f), and obtain the predicted value τ of the critical shear strength of the rock mass structural surface disturbance g ;

[0036] S7.3. Calculation of the critical shear strength test value τ of the rock mass structural surface disturbance c and the predicted value τ g The root mean square of the rock mass structure surface dynamic disturbance failure criterion G(σ n ,σ p ,A,f): in, is the internal friction angle, σ ρ is the lateral stress corresponding to the maximum shear stress of the rock mass structural surface, K is the lateral stress equal to the critical shear strength of the disturbance when the lateral stress is 0, and P, B, C, and D are model parameters.

[0037] The beneficial effects of the present invention are:

[0038] 1. Based on the critical shear strength of dynamic disturbance of rock structure surface under three-dimensional stress state, the present invention constructs a three-dimensional failure criterion of rock structure surface under the combined action of normal stress and lateral stress, dynamic disturbance stress amplitude and frequency, and fully characterizes the law of critical shear strength of disturbance of rock structure surface under three-dimensional stress.

[0039] 2. The present invention constructs the dynamic disturbance shear strength function of the rock structure surface under true three-dimensional stress through true triaxial shear test. The physical meaning of the parameters is clear and can be used as a criterion for shear failure of the rock structure surface of the tunnel engineering surrounding rock.

[0040] 3. After secondary development, the dynamic disturbance failure criterion of rock mass structural surface under true three-dimensional stress constructed by the present invention can be used for stability analysis and prediction of surrounding rock with structural surface in underground rock engineering. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a flow chart for constructing the dynamic disturbance failure criterion of the rock mass structural surface under true three-dimensional stress of the present invention;

[0042] Figure 2 is the critical shear strength of granite disturbance τ c Definition diagram of

[0043] Figure 3 The variation law of the critical shear strength of granite under different amplitude conditions;

[0044] Figure 4 The variation law of critical shear strength of granite under different frequency conditions;

[0045] Figure 5 The variation law of the perturbation critical shear strength of granite with normal stress under different normal stress conditions;

[0046] Figure 6 The variation law of the perturbation critical shear strength of granite with lateral stress under different lateral stress conditions;

[0047] Figure 7 The three-dimensional failure criterion and envelope surface of dynamic disturbance failure of granite structural surface considering amplitude and frequency effects;

[0048] Figure 8 It is the failure criterion, envelope surface and prediction of dynamic disturbance of rock mass structure surface under true three-dimensional stress of granite. DETAILED DESCRIPTION

[0049] 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.

[0050] Embodiment 1:

[0051] This embodiment provides a method for constructing and verifying the accuracy and rationality of the dynamic disturbance failure criterion of the rock structure surface under true three-dimensional stress using granite as a rock sample.

[0052] Figure 1 The flowchart of constructing the dynamic disturbance failure criterion of the rock mass structural surface under true three-dimensional stress is shown. The method includes steps S1 to S7:

[0053] In step S1, a true triaxial perturbation shear test is carried out to determine the shear stress at different normal stresses σ n and different lateral stresses σ p , critical shear strength τ of granite structural surface disturbance under different amplitudes A and different frequencies f c In the test, the shear stress and strain at each level under the condition of equal number of cycles are plotted against τ-ε τ Relationship curve cluster; the shear stress at the inflection point of the curve cluster slope mutation is defined as the perturbation critical shear strength τ c , the method to obtain is as follows Figure 2 As shown in Table 1, the critical shear strength of granite structural surface disturbance under different test conditions was calculated and statistically analyzed.

[0054] In step S2, the normal stress σ under true triaxial pressure is obtained. n , lateral stress σ p , frequency f and critical shear strength τ of rock mass structural surface disturbance under different amplitudes A c Change rules, such as Figure 3 As shown, the corresponding parameters a = 38.59MPa, b = 3.93MPa are obtained, and the critical shear strength G1(A) of the granite structural surface disturbance is determined at the same time: G1(A)=38.59+4.28·A -0.32

[0055] In step S3, the normal stress σ under true triaxial pressure is obtained. n , lateral stress σ p , amplitude A and critical shear strength τ of rock mass structural surface disturbance under different frequencies f c Change rules, such as Figure 4 As shown, the corresponding model parameters c = 44.09MPa, d = 2.53MPa, h = 12.38 are obtained, and the granite structural surface shear peak strength function G2(f) is determined and constructed: G2(f)=44.09+lg(12.38·f 2.53 )

[0056] In step S4, the same lateral stress σ under true triaxial pressure is obtained.p , amplitude A, frequency f and different normal stress σ n Critical shear strength τ of rock mass structural surface disturbance under c Change rules, such as Figure 5 As shown, the corresponding model parameters are obtained i=21.08MPa, and at the same time determine the critical shear strength G3(σ n ): G3(σ n )=σ n tan(59.5°)+21.08

[0057] In step S5, the normal stress σ under true triaxial pressure is obtained. n , amplitude A, frequency f and different lateral stress σ p Critical shear strength τ of rock mass structural surface disturbance under c Change rules, such as Figure 6 As shown, the corresponding model parameters are obtained: l = 35.54MPa, r = 10.16MPa, σ ρ =7.644MPa, K = 4.03MPa, and the critical shear strength G4 (σ p ):

[0058] In step S6, based on the shear peak strength law of the granite structural surface under different normal stresses and different lateral stresses, different amplitudes, and different frequencies in the three-dimensional stress state, the critical shear strength τ of the granite structural surface disturbance under the three-dimensional stress state is constructed. c The corresponding model parameters are b = 81.34MPa, h = 4.01MPa, m = -6.13, r=1.33MPa、σ ρ =7.77MPa, K = 2.67MPa, n = 19.36MPa to construct the critical shear strength function model G5 (σ n ,σ p ,A,f), and determine the envelope of the critical shear strength function of the rock mass structural surface disturbance as follows: Figure 7 Shown:

[0059] In step S7, Figure 8 As shown, the normal stress σ in S1 is different from that in n , lateral stress σ pThe true triaxial perturbation shear test of rock mass structure surface under the combination of amplitude A and frequency f is carried out to obtain the corresponding perturbation critical shear strength of rock mass structure surface, and verify and improve the perturbation critical shear strength function model G5(σ n ,σ p ,A,f), and obtain the predicted value τ of the critical shear strength of the rock mass structural surface disturbance g , as shown in Table 2; Calculate the critical shear strength test value τ of the rock mass structural surface disturbance c and the predicted value τ g The root mean square of the rock mass structure surface dynamic disturbance failure criterion G(σ n ,σ p ,A,f). Table 1 Disturbance critical shear strength of granite Table 2 Test values ​​and predicted values ​​of granite disturbance critical shear strength

[0060] 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. The dynamic disturbance failure criterion of rock mass structural surface under true three-dimensional stress includes the following steps: S1. Carry out true triaxial perturbation shear test to determine the normal stress σ n and different lateral stresses σ p , Critical shear strength τ of rock mass structural surface disturbance under different amplitude A and different frequency f c ; S2. Obtain the same normal stress σ under true triaxial n , lateral stress σ p , frequency f and critical shear strength τ of rock mass structural surface disturbance under different amplitudes A c The change law is used to construct the critical shear strength function model G1(A) of the rock mass structural surface disturbance. The method of constructing the critical shear strength function model G1(A) of the rock mass structural surface disturbance is as follows: S2.

1. Construct the normal stress σ under the same three-dimensional stress state based on the perturbation critical shear strength obtained in step S1 n , lateral stress σ p , frequency f and critical shear strength τ of rock mass structural surface disturbance under different amplitudes A c Laws of change; S2.

2. Construct the critical shear strength function model G1(A) of rock mass structural surface disturbance: G1(A)=a+b·A α Among them, a, b, and α are model parameters; S3. Obtain the same normal stress σ under true triaxial n , lateral stress σ p , amplitude A and critical shear strength τ of rock mass structural surface disturbance under different frequencies f c According to the law of change, the critical shear strength function model G2(f) of rock mass structural surface disturbance is constructed. The method of constructing the critical shear strength function model G2(f) of rock mass structural surface disturbance is as follows: S3.

1. Construct the normal stress σ under the same three-dimensional stress state based on the perturbation critical shear strength obtained in step S1 n , lateral stress σ p , amplitude A and critical shear strength τ of rock mass structural surface disturbance under different frequencies f c Laws of change; S3.

2. Construct the critical shear strength function model G2(f) of rock mass structural surface disturbance: G2(f)=c+lg(h·f d ) Among them, c, d, and h are model parameters; S4. Obtain the same lateral stress σ under true triaxial p , amplitude A, frequency f and different normal stress σ n Critical shear strength τ of rock mass structural surface disturbance under c The critical shear strength function model G3(σ n ), construct the critical shear strength function model G3(σ n ) is: S4.

1. Construct the same lateral stress σ under the three-dimensional stress state based on the perturbation critical shear strength obtained in step S1 p , amplitude A, frequency f and different normal stress σ n Critical shear strength τ of rock mass structural surface disturbance under c Laws of change; S4.

2. Construct the critical shear strength function model G3(σ n ): in, is the internal friction angle, i is the model parameter; S5. Obtain the same normal stress σ under true triaxial n , amplitude A, frequency f and different lateral stress σ p Critical shear strength τ of rock mass structural surface disturbance under c The critical shear strength function model G4(σ p ), construct the critical shear strength function model G4(σ p ) is: S5.

1. Construct the same normal stress σ under the three-dimensional stress state based on the perturbation critical shear strength obtained in step S1. n , amplitude A, frequency f and different lateral stress σ p Critical shear strength τ of rock mass structural surface disturbance under c Laws of change; S5.

2. Construct the critical shear strength function model G4(σ p ): Among them, l and r are model parameters, σ ρ is the lateral stress corresponding to the maximum rock shear stress, K is the lateral stress with the same strength as the critical shear strength of the disturbance when the lateral stress is 0; S6, based on steps S2 and S3, S4, S5, construct the critical shear strength function model G5 (σ n ,σ p ,A,f), determine the envelope of the critical shear strength function of the rock mass structural surface disturbance, and the method for determining the envelope of the critical shear strength function of the rock mass structural surface disturbance is: S6.

1. Based on the shear peak strength law of rock mass structural surface under different normal stresses, different lateral stresses, different amplitudes, and different frequencies in three-dimensional stress states, the critical shear strength τ of rock mass structural surface disturbance under three-dimensional stress states is constructed. c Laws of change; S6.

2. Construct the critical shear strength function model G5(σ n ,σ p ,A,f): Among them, b, d, h, and r are model parameters, and n is the cohesion; S6.3, according to the constructed rock mass structural surface disturbance critical shear strength function model, determine the envelope shape of the rock mass structural surface disturbance critical shear strength function; S7, develop normal stress σ different from S1 n , lateral stress σ p The true triaxial perturbation shear test of rock mass structure surface under the combination of amplitude A and frequency f is carried out to obtain the corresponding perturbation critical shear strength of rock mass structure surface, and verify and improve the perturbation critical shear strength function model G5(σ n ,σ p ,A,f), characterized by constructing the dynamic disturbance failure criterion G(σ n ,σ p ,A,f) is constructed as follows: S7.

1. Carry out the normal stress σ different from that in S1 n , lateral stress σ p , amplitude A and frequency f, and obtain the corresponding rock mass structural surface disturbance critical shear strength test value τ c ; S7.

2. Replace the normal stress σ in S7.1 with the normal stress σ in S1. n , lateral stress σ p , amplitude A and frequency f are substituted into the critical shear strength function model G5(σ n ,σ p ,A,f), and obtain the predicted value τ of the critical shear strength of the rock mass structural surface disturbance g ; S7.

3. Calculation of the critical shear strength test value τ of the rock mass structural surface disturbance c and the predicted value τ g The root mean square of the rock mass structure surface dynamic disturbance failure criterion G(σ n ,σ p ,A,f): in, is the internal friction angle, σ ρ is the lateral stress corresponding to the maximum shear stress of the rock mass structural surface, K is the lateral stress equal to the critical shear strength of the disturbance when the lateral stress is 0, and P, B, C, D, and m are model parameters.

2. The dynamic disturbance failure criterion of rock mass structural surface under true three-dimensional stress as claimed in claim 1 is characterized in that: In step S1, different normal stresses σ n and different lateral stresses σ p , true triaxial perturbation shear test under different amplitudes A and different frequencies f, and obtain the corresponding perturbation critical shear strength τ c for: S1.

1. Test data of rock mass structural surface disturbance shear failure under different test conditions obtained through true triaxial disturbance shear test; S1.

2. Take the shear stress and strain at each level under the condition of equal number of cycles and plot τ-ε τ Relationship curve cluster; S1.

3. The shear stress at the inflection point of the curve cluster slope mutation is defined as the perturbation critical shear strength τ c ; S1.

4. Calculate and statistically analyze the critical shear strength of rock mass structural surface disturbance under different test conditions.

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