Method, device, equipment and medium for judging crack extension in deep layered rocks based on microstructure tensor

Abstract

The present invention provides a method, device, equipment and medium for judging the extension of deep layered rock cracks based on microstructure tensors, and relates to the technical field of rock mechanics. In an embodiment of the present invention, in order to better describe the anisotropic behavior of shear slip fractures of deep layered rocks, the deviator of the layered rock microstructure tensor is introduced, and the layered rock anisotropic state parameters are constructed with the joint invariant of the deviator stress tensor, and a method for judging the extension of deep layered rock cracks is established, which can not only describe the influence of the original anisotropy of deep layered rocks on shear slip fractures under the condition of rotation of the principal stress direction, but also describe the influence of the stress-induced anisotropy caused by the rotation of the principal stress direction on the shear slip fracture strength of deep layered rocks.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of rock mechanics technology, and in particular to a method, device, equipment and medium for judging the extension of deep layered rock cracks based on microstructure tensors. Background Art

[0002] Layered rock is a type of anisotropic rock often encountered in geotechnical engineering. For example, slate, schist, sandstone and shale are more common in tunnel engineering and oil and gas resource extraction. The expansion of cracks in rocks will significantly reduce the stability of the tunnel surrounding rock, and at the same time increase the permeability of the rock formation. Therefore, studying the fracture behavior of rocks is of great significance to geotechnical engineering. Previous studies have shown that under the combined influence of natural cracks, bedding weak planes and stress environment, shear failure often occurs in rock masses in underground engineering. Since underground rock masses with natural cracks are mainly affected by tectonic stress and compressive stress generated by their own weight, the expansion of cracks inside the rock may occur in the direction of maximum shear stress in the form of shear slip. This kind of fracture expands in a self-similar manner and is very common in deep strata.

[0003] Rock crack propagation criteria are an important part of rock failure theory. For layered rocks, experimental results show that their fracture characteristics are significantly different from those of isotropic rocks, and their complex failure mechanism makes it difficult to establish crack propagation criteria. Compared with the past, domestic and foreign scholars have conducted a lot of exploration on the compression strength criterion and Brazilian splitting strength criterion of layered rocks, but there is still little research on the anisotropic crack propagation criteria of deep layered rocks. How to theoretically quantify the anisotropy of the fracture characteristics of deep layered rocks is still a difficult problem. Summary of the invention

[0004] The embodiments of the present invention provide a method, device, equipment and medium for judging the extension of deep layered rock cracks based on microstructure tensor.

[0005] A first aspect of an embodiment of the present invention provides a method for judging the extension of deep layered rock cracks based on microstructure tensors, the method comprising:

[0006] Based on the deviator and deviator stress tensor of the microstructure tensor of the layered rock, the anisotropic state parameter A of the layered rock is determined. A represents the interaction between the external load and the material fabric direction.

[0007] Determination of the mode I stress intensity factor K at the fracture tip of deep layered rock in Cartesian coordinate system I and type II stress intensity factor K II ;

[0008] In K II >K IIC -μK I Under the circumstances, it is determined that the deep layered rock cracks will expand;

[0009] Among them, K IIC =K IIC0 [1+K IIC1 ·A+K IIC2 (A) 2 ];μ=μ0[1+μ1·A+μ2·(A) 2 ];

[0010] K IIC0 ,K IIC1 ,K IIC2 With μ0, μ1, and μ2 as material parameters, based on the test results of mode II fracture of layered rocks with different bedding angles, the numerical approximation method is used to obtain K IIC0 ,K IIC1 ,K IIC2 The optimal solution for μ0, μ1, μ2.

[0011] Optionally, the method further comprises: calculating the unitized deviatoric stress tensor d based on the following formula: ij :

[0012]

[0013] Among them, the deviator stress tensor

[0014] The stress tensor on the unit cell near the crack tip of deep layered rock is

[0015]

[0016] r represents the polar coordinate radius of the point near the crack tip, and T represents the T stress.

[0017] Alternatively, the deviator of the layered rock microstructure tensor is calculated based on

[0018]

[0019] Among them, the partial microstructure tensor δ ij is defined as when i = j, δ ij =1 otherwise, δ ij =0.

[0020] Optionally, the method further comprises:

[0021] Based on the following formula and the test results of multiple groups of layered rock type I fractures with different bedding angles, the numerical approximation method is used to obtain K ⅠC0 , K ⅠC1 , K ⅠC2 The optimal solution corresponding to Δ:

[0022]

[0023] Among them, α represents the angle between the crack extension direction and the bedding direction in the test results, K IC represents the pure mode I fracture toughness obtained from the test results, K ⅠC0 ,K ⅠC1 ,K ⅠC2 is a material parameter, and the parameter Δ is used to quantitatively describe the initial anisotropy degree of the layered rock material itself.

[0024] Optionally, determining an anisotropic state parameter A of the layered rock based on the deviator and the deviator stress tensor of the layered rock microstructure tensor comprises:

[0025] The anisotropic state parameter A of the material is calculated based on the following formula:

[0026]

[0027] Among them, θ represents the angle between the maximum principal stress direction of layered rock load and the bedding normal direction.

[0028] A second aspect of an embodiment of the present invention provides a device for judging the extension of deep layered rock cracks based on microstructure tensors, the device comprising:

[0029] The first determination module is used to determine the anisotropic state parameter A of the layered rock based on the deviator and deviator stress tensor of the layered rock microstructure tensor, where A represents the interaction between the external load and the material structure direction;

[0030] The second determination module is used to determine the I-type stress intensity factor K at the tip of the deep layered rock crack in the Cartesian coordinate system. I and type II stress intensity factor K II ;

[0031] The third determination module is used to II >K IIC -μK I Under the circumstances, it is determined that the deep layered rock cracks will expand;

[0032] Among them, K IIC =K IIC0 [1+K IIC1 ·A+K IIC2 (A) 2 ];μ=μ0[1+μ1·A+μ2·(A) 2 ];

[0033] K IIC0 ,K IIC1 ,K IIC2With μ0, μ1, and μ2 as material parameters, combined with multiple groups of mode II fracture test results of layered rocks with different bedding inclinations, the numerical approximation method is used to obtain the corresponding optimal solution.

[0034] Optionally, the device further includes: a first calculation module, configured to:

[0035] The normalized deviator stress tensor d is calculated based on the following formula: ij :

[0036]

[0037] Among them, the deviator stress tensor

[0038] The stress tensor on the unit cell near the crack tip of deep layered rock is

[0039]

[0040] r represents the polar coordinate radius of the point near the crack tip, and T represents the T stress.

[0041] Optionally, the device further includes: a second calculation module, configured to:

[0042] The deviator of the layered rock microstructure tensor is calculated based on the following formula:

[0043]

[0044] Among them, the partial microstructure tensor δ ij is defined as when i = j, δ ij =1 otherwise, δ ij =0.

[0045] Optionally, the device further comprises:

[0046] The third calculation module uses a numerical approximation method to calculate K based on the following formula and the test results of the multiple groups of layered rock type I fractures with different bedding angles: ⅠC0 , K ⅠC1 , K ⅠC2 The optimal solution corresponding to Δ:

[0047]

[0048] Among them, α represents the angle between the crack extension direction and the bedding direction in the test results, K IC represents the pure mode I fracture toughness obtained from the test results, K ⅠC0 ,K ⅠC1 ,K ⅠC2 is a material parameter, and the parameter Δ is used to quantitatively describe the initial anisotropy degree of the layered rock material itself.

[0049] Optionally, the first determining module is specifically configured to:

[0050] The anisotropic state parameter A of the material is calculated based on the following formula:

[0051]

[0052] Among them, θ represents the angle between the maximum principal stress direction of layered rock load and the bedding normal direction.

[0053] A third aspect of an embodiment of the present invention provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executed, implements the method for determining the extension of deep layered rock fractures based on microstructure tensors as described in the first aspect of the present invention.

[0054] A fourth aspect of an embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method for determining the extension of deep layered rock fractures based on microstructure tensors as described in the first aspect of the present invention.

[0055] A fifth aspect of an embodiment of the present invention provides a computer program product, including a computer program / instruction, which is used by a processor to implement the steps of the method for determining deep layered rock fracture extension based on microstructure tensors as described in the first aspect of the present invention.

[0056] In an embodiment of the present invention, in order to better describe the anisotropic behavior of shear slip fracture of deep layered rocks, the deviator of the layered rock microstructure tensor is introduced, and the anisotropic state parameters of the layered rock are constructed with the joint invariant of the deviatoric stress tensor, and a method for judging the extension of deep layered rock cracks is established. It can not only describe the influence of the original anisotropy of deep layered rocks on shear slip fracture under the condition of rotation of the principal stress direction, but also describe the influence of the stress-induced anisotropy caused by the rotation of the principal stress direction on the shear slip fracture strength of deep layered rocks. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0058] Figure 1 is a schematic diagram of the structural orientation of sedimentary rocks provided by an embodiment of the present invention;

[0059] Figure 2It is a schematic diagram of point A near the crack tip in the expansion direction of a compression-shear type crack in a Cartesian coordinate system (x, y) provided by an embodiment of the present invention;

[0060] Figure 3 A deep layered rock fracture stress model provided by an embodiment of the present invention;

[0061] Figure 4 Schematic diagram of a three-point bending loading experiment of a single-side notched deep beam specimen of layered rock with different bedding inclination angles provided by an embodiment of the present invention;

[0062] Figure 5 It is a schematic diagram of a direct shear loading experiment of a single-side cut-groove specimen of layered rock with different bedding inclination angles provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0063] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0064] Rocks, granular soils, etc. are often formed by material particles arranged and combined according to a specific rule. The anisotropy of their macroscopic mechanical response must be determined by the arrangement of the microstructure inside the material load unit, such as voids, microcracks, and contact between particles. The material microstructure tensor can quantitatively describe the distribution law of the internal microstructure of such granular materials, and it can be proved that the material microstructure tensor can be expressed by a second-order tensor F ij To quantify. Shale and other layered rocks are typical sedimentary rocks with visible stratification structures. Their macroscopic mechanical characteristics have obvious anisotropy. The evolution of the anisotropic characteristics of the internal structure of the material can also be described by the material microstructure tensor F'. For orthogonal anisotropic materials with material symmetry planes, it can be further proved that their microstructure tensor is symmetrical, and the components of F' can be transformed into the three principal values ​​F corresponding to the direction of the material symmetry axis. 11 ,F 22 and F 33 Furthermore, the layered rock material usually takes the natural depositional surface as the isotropic surface. In order to describe its transversely isotropic behavior, Figure 1 As shown in the figure, it shows a schematic diagram of the structural direction of sedimentary rocks, where the dotted line represents the natural bedding plane. Specifically, it is assumed that the x2–x3 direction in the Cartesian coordinate system is the sedimentary plane (i.e., the isotropic plane), and F 11 The direction is perpendicular to the deposition surface, then the other two principal values ​​satisfy F 22 =F 33 , the layered rock microstructure tensor F′ can be expressed as:

[0065]

[0066] In formula (1), the parameter Δ is used to quantitatively describe the initial anisotropy of the layered rock material itself. In general, the Δ value satisfies 0≤Δ≤1. The larger the Δ, the higher the initial anisotropy of the layered rock. When describing isotropic materials, F 11 =F 22 =F 33 =1 / 3, the corresponding Δ=0; when the long axes of all particles of the sedimentary rock are in the transverse isotropic plane, the anisotropy of the material is the largest, at this time Δ=1.

[0067] The orthogonal anisotropic surface of layered rock perpendicular to the bedding plane, that is, the x1-x2 plane in the coordinate system, can be degenerated into a two-dimensional anisotropic problem. At this time, the layered rock microstructure tensor F′ degenerates into the following second-order tensor form, namely:

[0068]

[0069] If the coordinate axes of the reference coordinate system are established in the direction of the principal stress of the unit body, for the case where the material principal axis (such as the bedding normal direction of layered rock) does not coincide with the principal stress direction, the layered rock microstructure tensor F′ constructed in the direction of the material principal axis is converted to the layered rock microstructure tensor F in the reference coordinate system established with three principal stress directions:

[0070]

[0071] In formula (3), Q is the coordinate transformation matrix, i, j, k, l represent the positions in the second-order matrix, θ is the angle between the maximum principal stress direction of the unit body and the bedding normal direction, and F k ' l is the component of the microstructure tensor in the direction of the material's principal axes.

[0072] Furthermore, a deviator for calculating the microstructure tensor of layered rock from the microstructure tensor F is defined as:

[0073]

[0074] Among them, the partial microstructure tensor δ ij is defined as when i = j, δ ij =1 otherwise, δ ij =0.

[0075] Under the combined action of tectonic stress and compressive stress generated by its own weight, underground rock masses with natural cracks are subjected to the combined action of pressure and shear force, and self-similarly expand along the direction of maximum shear stress. In the direction of crack expansion, Figure 2 As shown, Figure 2 The schematic diagram of point A near the crack tip in the direction of expansion of the compression-shear crack in the Cartesian coordinate system (x, y) is shown. The stress state of point A near the crack tip is

[0076]

[0077] In formula (5), the T stress is parallel to σ xx ,like Figure 2 As shown, r represents the polar coordinate radius of point A near the crack tip.

[0078] For the shear slip fracture process of deep rock mass, the stress state at the crack tip is the dominant factor controlling the expansion of rock cracks, and also dominates the generation of induced anisotropy. When analyzing the anisotropic characteristics of shear slip fracture of deep layered rock, the stress model of deep layered rock cracks is expressed as follows: Figure 3 As shown, the left figure is a schematic diagram of the force on deep layered rock fractures, the middle figure shows the stress state of the unit body at the fracture tip, and the right figure shows the principal stress direction and fabric direction of the unit body at the fracture tip. In the figure, α is the angle between the crack extension direction and the bedding direction, and θ is the angle between the maximum principal stress direction and the bedding normal direction.

[0079] The stress tensor on the unit cell at the tip of a deep layered rock fracture is:

[0080]

[0081] The deviator stress tensor can be calculated as

[0082]

[0083] Furthermore, in order to characterize the direction of the stress tensor, a unitized deviatoric stress tensor d is defined:

[0084]

[0085] It is easy to see from the above formula that the normalized deviatoric stress tensor satisfies trd = 0 and trd 2 =1, so d only represents the direction of the stress tensor but cannot represent the magnitude of the stress.

[0086] In order to quantitatively describe the physical mechanism response of the material microstructure under stress in different directions, considering the relationship between the initial anisotropy caused by the intrinsic microstructure distribution of the material and the external influence of the load on the anisotropy of the material, the embodiment of the present invention defines a new scalar anisotropic state parameter A that characterizes the interaction between the external load and the material structure direction.

[0087]

[0088] It should be noted that the anisotropic state parameter A defined here based on the stress on the unit cell at the tip of the deep layered rock fracture is determined by three factors: the anisotropy degree of the layered rock itself, which is expressed as the specific component value F of the material microstructure tensorij , determined by the value of Δ; the direction of material anisotropy, that is, the direction of the microstructure tensor relative to the reference coordinate system, is determined by the angle α; the direction of the stress tensor relative to the reference coordinate system. The first two are the intrinsic anisotropies determined by the layered rock material itself, while the direction of the stress tensor determines the induced anisotropy caused by the stress state, stress path, etc. acting on the anisotropic material. At the same time, it can be found that the formula (9) for calculating A is a stress intensity factor K II and the 0th-order homogeneous function of T stress, so K II The magnitude of the stress level of T will not affect the value of A, that is, increasing or decreasing K in the same proportion II And T stress will not change the value of A. At the same time, it can be seen that when Δ = 0, A ≡ 0, and the material described is isotropic.

[0089] We continue to explore the quantitative calculation of the influence of the internal structure arrangement of the material and the interaction with the external stress on the macroscopic mechanical response of the layered rock by introducing the anisotropic state parameter A. Assuming that the failure criterion of the anisotropic material is determined by the stress σ and the material microstructure tensor F, the form of the failure criterion can be expressed by introducing A as

[0090] g=g(σ,F)=g(σ ij ,A)=0 (10)

[0091] Because the strength parameters of layered rocks all show anisotropic characteristics that change with the load direction, their strength parameters can be expressed in the form of formula (10) by introducing A.

[0092] When K II When it is 0, it degenerates into a pure I-type fracture. In formula (9), let K II = 0, the anisotropic state parameter A of the material is simplified to a quantity that is only determined by the bedding direction and has nothing to do with the loading process:

[0093]

[0094] For typical layered materials such as layered rocks, the pure mode I fracture strength parameter should be expressed as a quantity related to the bedding direction. According to formula (10), the pure mode I fracture toughness considering the anisotropic characteristics of the layered rock strength can be expressed as:

[0095] K IC =K IC (σ,F)=K IC (σ,A) (12)

[0096] The function in the above formula is approximated by expanding it with its zero-order, second-order, fourth-order and higher-order microstructure tensors, namely:

[0097] K IC =K IC0 (1+F ij d ij +F ijkl d ijkl +F ijklmn d ijklmn +…) (13)

[0098] Considering the simplified conditions, the terms in the above formula can be written as F ijkl d ijkl =f c1 F ij F kl d ij d kl ,F ijklmn d ijklmn =f c2 F ij F kl F mn d ij d kl d mn , etc., so the formula can be further expanded as:

[0099]

[0100] At this time, the above formula expresses the pure mode I fracture toughness of layered rock as a function of the anisotropic state parameter A, where f c0 ,f c1 and f c2 is the material parameter to be determined. Based on the relative orientation of the main axis of the layered material and the loading direction of the pure I-mode fracture test, formula (14) can be further written as:

[0101]

[0102] Combined with multiple sets of layered rock type I fracture tests with different bedding angles (such as Figure 4 Schematic diagram of the three-point bending loading experiment of single-sided notched deep beam specimens in layered rock with different bedding inclinations, where the dotted line represents the bedding plane of the layered rock). The value of the parameter Δ can be fitted by using numerical approximation methods (such as the least squares method).

[0103] In the embodiment of the present invention, K I , K II The stresses K and T are determined by the loading state and geometry. For specimens of any geometry and loading state, the K can be obtained by numerical calibration of the specimen. I , K II and T stress.

[0104] Specifically, for Figure 4The single-side notched deep beam specimen shown in the figure can be determined by the following method:

[0105] Among them, Y I and Y II They are the dimensionless shape factors of type I and type II, respectively, which are obtained by numerical calibration of the specimen, where W represents the width of the specimen, P represents the vertical load currently borne, a represents the length of the cut, and B represents the thickness of the specimen.

[0106] In the embodiment of the present invention, the Coulomb model is further introduced to predict the extension of deep rock shear cracks, which can be expressed as:

[0107] K II =K IIC -μK I (16)

[0108] In the formula, K IIC is unconstrained (i.e., K I =0) condition, μ is the shear fracture toughness of rock, and μ is the friction coefficient.

[0109] For isotropic materials, the Coulomb model assumes that μ and K IIC is a constant, while for typical anisotropic materials such as layered rocks, the shear fracture strength parameters μ and K IIC All should be expressed as stress-direction related quantities. Assuming that the shear fracture strength parameter describing the material changes continuously with the anisotropic state parameter A, the shear fracture toughness K of the rock under unconstrained layered rock is IIC Both material parameters, φ and friction coefficient μ, are considered as functions of A. According to formula (14), the quadratic form of A is as follows:

[0110] K IIC (A) = K IIC0 [1+K IIC1 ·A+K IIC2 (A) 2 ] (17)

[0111] μ(A)=μ0[1+μ1·A+μ2·(A) 2 ] (18)

[0112] The two sets of coefficients (K) in equations (17) and (18) IIC0 ,K IIC1 ,K IIC2 and μ0, μ1, μ2) are material parameters, which can be combined with multiple sets of layered rock type II fracture tests with different bedding angles (e.g. Figure 5Schematic diagram of direct shear loading experiment of single-side notched specimens in layered rock with different bedding inclination angles, where the dotted line represents the bedding plane of layered rock), and the corresponding optimal solution is obtained by numerical approximation method.

[0113] During the shear fracture of deep rocks, the anisotropic state parameter A is determined by the bedding direction and the current stress state during the loading process. The anisotropic state parameter A during the loading process needs to be calculated by formula (9).

[0114] Based on the above research and exploration, an embodiment of the present invention provides a method for judging the extension of deep layered rock cracks based on microstructure tensor, which may include the following steps:

[0115] S101, determining the anisotropic state parameter A of the layered rock based on the deviator of the layered rock microstructure tensor and the deviatoric stress tensor, where A represents the interaction between the external load and the material fabric direction;

[0116] S102, Determine the mode I stress intensity factor K at the tip of a deep layered rock fracture in the Cartesian coordinate system I and type II stress intensity factor K II ;

[0117] S103, in K II >K IIC -μK I Under the circumstances, it is determined that the deep layered rock cracks will expand;

[0118] Among them, K IIC =K IIC0 [1+K IIC1 ·A+K IIC2 (A) 2 ];μ=μ0[1+μ1·A+μ2·(A) 2 ];

[0119] K IIC0 ,K IIC1 ,K IIC2 With μ0, μ1, and μ2 as material parameters, combined with multiple groups of mode II fracture test results of layered rocks with different bedding inclinations, the numerical approximation method is used to obtain the corresponding optimal solution.

[0120] In the embodiment of the present invention, the deviator of the layered rock microstructure tensor can be calculated based on the above formula (4): Based on the above formulas (6), (7), and (8), the normalized deviatoric stress tensor d is calculated as ij .

[0121] In the embodiment of the present invention, based on formula (4) and formulas (6), (7), and (8), formula (9) can be obtained, which is used to calculate the scalar anisotropic state parameter A that characterizes the interaction between the external load and the material structure direction.

[0122] In an embodiment of the present invention, in order to calculate the value of parameter Δ in formula (9) for quantitatively describing the initial anisotropy degree of the layered rock material itself, formula (15) can also be used in combination with multiple groups of layered rock type I fracture tests with different bedding angles, and a numerical approximation method (such as the least squares method) can be used to fit the value of parameter Δ.

[0123] Therefore, in the embodiment of the present invention, in order to better describe the anisotropic behavior of shear slip fracture of deep layered rocks, the deviator of the layered rock microstructure tensor is introduced, and the anisotropic state parameter of the layered rock is constructed with the joint invariant of the deviatoric stress tensor, and a method for judging the extension of deep layered rock cracks is established. In the embodiment of the present invention, not only can the influence of the native anisotropy of deep layered rocks on shear slip fracture under the condition of rotation of the principal stress direction be described, but also the influence of the stress-induced anisotropy caused by the rotation of the principal stress direction on the shear slip fracture strength of deep layered rocks can be described.

[0124] Based on the same inventive concept, an embodiment of the present invention further provides a device for judging the extension of deep layered rock cracks based on microstructure tensors, the device comprising:

[0125] The first determination module is used to determine the anisotropic state parameter A of the layered rock based on the deviator and deviator stress tensor of the layered rock microstructure tensor, where A represents the interaction between the external load and the material structure direction;

[0126] The second determination module is used to determine the I-type stress intensity factor K at the tip of the deep layered rock crack in the Cartesian coordinate system. I and type II stress intensity factor K II ;

[0127] The third determination module is used to II >K IIC -μK I Under the circumstances, it is determined that the deep layered rock cracks will expand;

[0128] Among them, K IIC =K IIC0 [1+K IIC1 ·A+K IIC2 (A) 2 ];μ=μ0[1+μ1·A+μ2·(A) 2 ];

[0129] K IIC0 ,KIIC1 ,K IIC2 With μ0, μ1, and μ2 as material parameters, combined with multiple groups of mode II fracture test results of layered rocks with different bedding inclinations, the numerical approximation method is used to obtain the corresponding optimal solution.

[0130] Optionally, the device further includes: a first calculation module, configured to:

[0131] The normalized deviator stress tensor d is calculated based on the following formula: ij :

[0132]

[0133] Among them, the deviator stress tensor

[0134] The stress tensor on the unit cell near the crack tip of deep layered rock is

[0135]

[0136] r represents the polar coordinate radius of the point near the crack tip, and T represents the T stress.

[0137] Optionally, the device further includes: a second calculation module, configured to:

[0138] The deviator of the layered rock microstructure tensor is calculated based on the following formula:

[0139]

[0140] Among them, the partial microstructure tensor δ ij is defined as when i = j, δ ij =1 otherwise, δ ij =0.

[0141] Optionally, the device further comprises:

[0142] The third calculation module uses a numerical approximation method to calculate K based on the following formula and the test results of the multiple groups of layered rock type I fractures with different bedding angles: ⅠC0 , K ⅠC1 , K ⅠC2 The optimal solution corresponding to Δ:

[0143]

[0144] Among them, α represents the angle between the crack extension direction and the bedding direction in the test results, K IC represents the pure mode I fracture toughness obtained from the test results, K ⅠC0 ,K ⅠC1 ,K ⅠC2is a material parameter, and the parameter Δ is used to quantitatively describe the initial anisotropy degree of the layered rock material itself.

[0145] Optionally, the first determining module is specifically configured to:

[0146] The anisotropic state parameter A of the material is calculated based on the following formula:

[0147]

[0148] Among them, θ represents the angle between the maximum principal stress direction of layered rock load and the bedding normal direction.

[0149] Based on the same inventive concept, an embodiment of the present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes, the steps in the method for determining the extension of deep layered rock fractures based on microstructure tensors as described in any of the above embodiments are implemented.

[0150] Based on the same inventive concept, an embodiment of the present invention further provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the steps of the method for determining deep layered rock crack extension based on microstructure tensor described in any of the above embodiments are implemented.

[0151] Based on the same inventive concept, an embodiment of the present invention provides a computer program product, including a computer program / instruction, which, when executed by a processor, implements the steps of the method for determining deep layered rock fracture extension based on microstructure tensor described in any of the above embodiments.

[0152] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0153] It will be appreciated by those skilled in the art that the embodiments of the present invention may be provided as methods, devices, or computer program products. Therefore, the embodiments of the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the embodiments of the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0154] The embodiments of the present invention are described with reference to the flowcharts and / or block diagrams of the methods, terminal devices (apparatus), and computer program products according to the embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of the processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable terminal device to generate a machine, so that the instructions executed by the processor of the computer or other programmable terminal device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0155] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable terminal device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0156] These computer program instructions can also be loaded onto a computer or other programmable terminal device so that a series of operating steps are executed on the computer or other programmable terminal device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable terminal device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0157] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the embodiments of the present invention.

[0158] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or terminal device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or terminal device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or terminal device including the elements.

[0159] The above is a detailed introduction to a method for judging the extension of deep layered rock cracks based on microstructure tensors provided by the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for general technicians in this field, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A method for judging the extension of deep layered rock cracks based on microstructure tensor, characterized in that: The method comprises: Determination of anisotropic state parameters of layered rocks based on the deviator of the layered rock microstructure tensor and the deviatoric stress tensor A, A Characterize the interaction between external load and material configuration direction; Determination of the Mode I Stress Intensity Factor at the Tip of a Fracture in Deep Layered Rocks in Cartesian Coordinates K I and type II stress intensity factor K II ; exist Under the circumstances, it is determined that the deep layered rock cracks will expand; in, ; ; K IIC0 , K IIC1 , K IIC2 and μ 0, μ 1, μ 2 is the material parameter. Based on the test results of type II fracture of layered rocks with different bedding angles, the numerical approximation method is used to obtain K IIC0 , K IIC1 , K IIC2 and μ 0, μ 1, μ The optimal solution of 2; Determination of anisotropic state parameters of layered rocks based on the deviator of the layered rock microstructure tensor and the deviatoric stress tensor A ,include: The anisotropic state parameters of the material are calculated based on the following formula A : ； in, θ The angle between the maximum principal stress direction of the layered rock load and the bedding normal direction; represents the normalized deviatoric stress tensor, represents the deviator of the layered rock microstructure tensor, T express T stress; r represents the polar coordinate radius of the point near the crack tip; i, j Represents a position in a second-order matrix.

2. The method for judging the extension of deep layered rock cracks based on microstructure tensor according to claim 1 is characterized in that: The method further includes calculating a normalized deviatoric stress tensor based on the following formula: : ； Among them, the deviator stress tensor ; The stress tensor on the unit cell near the crack tip of deep layered rock is .

3. The method for judging the extension of deep layered rock cracks based on microstructure tensor according to claim 1 is characterized in that: The method further comprises: calculating the deviator of the layered rock microstructure tensor based on the following formula: : ； ; Q is the coordinate transformation matrix, i, j, k, l represents the position in the second-order matrix; is the component of the microstructure tensor in the direction of the material's principal axis; Among them, the partial microstructure tensor δ ij is defined as i=j hour, δ ij =1 otherwise, δ ij =0; F ij is the specific component value of the material microstructure tensor.

4. The method for judging the extension of deep layered rock cracks based on microstructure tensor according to claim 3 is characterized in that: The method further comprises: Based on the following formula and the test results of multiple groups of layered rock type I fractures with different bedding angles, the numerical approximation method is used to obtain K ⅠC0 , K ⅠC1 , K ⅠC2 The optimal solution corresponding to Δ: ; in, α Indicates the angle between the crack extension direction and the bedding direction in the test results, represents the pure mode I fracture toughness obtained from the test results, K ⅠC0 , K ⅠC1 , K ⅠC2 is a material parameter, and the parameter Δ is used to quantitatively describe the initial anisotropy degree of the layered rock material itself.

5. A device for judging the extension of deep layered rock cracks based on microstructure tensor, characterized in that: The device comprises: The first determination module is used to determine the anisotropic state parameters of the layered rock based on the deviator and deviator stress tensor of the layered rock microstructure tensor A, A Characterize the interaction between external load and material configuration direction; The second determination module is used to determine the I-type stress intensity factor at the tip of the deep layered rock crack in the Cartesian coordinate system K I and type II stress intensity factor K II ; The third determination module is used to Under the circumstances, it is determined that the deep layered rock cracks will expand; in, ; ; K IIC0 , K IIC1 , K IIC2 and μ 0, μ 1, μ 2 is the material parameter. Based on the test results of mode II fracture of multiple groups of layered rocks with different bedding inclinations, the corresponding optimal solution is obtained by numerical approximation method. The first determining module is specifically configured to: The anisotropic state parameters of the material are calculated based on the following formula A : ； in, θ The angle between the maximum principal stress direction of the layered rock load and the bedding normal direction; represents the normalized deviatoric stress tensor, represents the deviator of the layered rock microstructure tensor, T express T stress; r represents the polar coordinate radius of the point near the crack tip; i, j Represents a position in a second-order matrix.

6. The device for judging the extension of deep layered rock cracks based on microstructure tensor according to claim 5 is characterized in that: The device also includes: The first calculation module is used to calculate the normalized deviatoric stress tensor based on the following formula : ； Among them, the deviator stress tensor ; The stress tensor on the unit cell at the tip of a deep layered rock fracture is: .

7. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the method for judging the extension of deep layered rock cracks based on microstructure tensors as described in any one of claims 1 to 4 is implemented.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method for judging the extension of deep layered rock cracks based on microstructure tensors as described in any one of claims 1 to 4 is implemented.

9. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instruction is executed by a processor, the steps of the method for determining the extension of deep layered rock fractures based on microstructure tensors as described in any one of claims 1 to 4 are implemented.

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