A numerical simulation prediction method and system for anisotropic rock mass thermal coupling fracture analysis

Abstract

This invention belongs to the field of numerical simulation of rock mechanics and fracture mechanics, and discloses a numerical simulation prediction method and system for thermo-mechanical coupling fracture analysis of anisotropic rock masses. The method includes: Step 1: Constructing a peri-field dynamic model, inputting specific parameters of materials, geometry, and peri-field dynamics, identifying and calibrating the principal direction angles of the materials, and using angle tolerance to identify reinforcing bonds along the principal direction, as well as isotropic peri-field dynamic bonds; Step 2: Performing heat conduction analysis based on the initialized peri-field dynamic model; Step 3: Introducing the calculated temperature field into the force density function through thermal expansion correction, and using the ADR method for quasi-static solution to calculate the force field deformation; Step 4: Based on the force field deformation, using the critical elongation-based bond failure criterion to determine the state of the peri-field dynamic bonds, thereby tracing the crack propagation path.

Description

Technical Field

[0001] This invention belongs to the field of numerical simulation of rock mechanics and fracture mechanics, and specifically relates to a numerical simulation prediction method and system for thermo-mechanical coupling fracture analysis of anisotropic rock masses. Background Technology

[0002] Rock mechanics engineering is often conducted in extreme deep-earth environments characterized by high geothermal temperatures and high geostress. Under these extreme conditions, thermally induced fractures caused by drastic temperature gradient changes or localized thermal shocks become a major cause of structural damage and even destruction. The widespread presence of oriented bedding planes within rock masses results in significant thermal and mechanical anisotropy. Numerous high-temperature rock mechanics tests have confirmed that the mechanical properties of anisotropic rock masses exhibit directional differences. Due to the high cost of experiments, numerical simulation has become a crucial tool for investigating thermo-mechanically coupled fracture behavior. The classical finite element method (FEM) suffers from stress singularities in its spatial derivatives when dealing with geometrically discontinuous boundaries such as crack tips. The extended finite element method (EPM) introduces enrichment functions to characterize crack surface jumps, but this significantly increases computational complexity, particularly when handling complex morphologies such as multiple crack intersections and branches under thermo-mechanical coupling. Furthermore, while element deletion methods and cohesion models alleviate singularities, they rely on pre-defined crack propagation paths and are constrained by mesh dependence.

[0003] Therefore, a novel numerical simulation and prediction method for thermo-mechanical coupled damage is needed that takes into account the anisotropy of heat conduction and thermal expansion deformation, and can naturally simulate crack paths. Summary of the Invention

[0004] To address the problems of existing technologies, this invention provides a numerical simulation prediction method and system for thermo-mechanical coupling fracture analysis of anisotropic rock masses. The method sequentially establishes an anisotropic rock mass model and initializes material parameters; introduces anisotropic heat conduction equations enhanced by the principal direction for thermal field analysis; and incorporates direction-dependent thermal expansion effects into the force field constitutive relation for stress field solution. Finally, it utilizes a bond-breaking criterion based on anisotropic critical elongation to simulate and predict crack initiation and propagation. This invention effectively avoids the singularity problem in continuum mechanics when dealing with cracks and can accurately predict the fracture and failure evolution process of anisotropic rock masses under extreme thermal environments.

[0005] To achieve the above objectives, the present invention provides the following solution: A numerical simulation prediction method for thermo-mechanical coupled fracture analysis of anisotropic rock masses, the method comprising: Step 1: Construct a peri-field dynamics model by inputting specific parameters of the material, geometry, and peri-field dynamics, identifying and calibrating the principal direction angles of the material, and using the angle tolerance to identify reinforcing bonds along the principal direction, as well as isotropic peri-field dynamic bonds; Step 2: Perform heat conduction analysis based on the initialized near-field dynamics model; Step 3: Introduce the calculated temperature field into the force density function through thermal expansion correction, and use the ADR method to perform quasi-static solution to calculate the force field deformation; Step 4: Based on the force field deformation, use the critical elongation rate to determine the state of the near-field dynamic bond and thus track the crack propagation path.

[0006] Preferably, in step one, the identification of anisotropic bonds is as follows: apart from isotropic basic bonds, when the angle between the bond direction of the connecting material point and the main direction of the rock mass or the direction perpendicular to the main direction is within the tolerance range, the bond is defined as a reinforcing bond along the main direction or a reinforcing bond along the direction perpendicular to the main direction, thus completing the model direction bond identification initialization.

[0007] Preferably, in step two, the method for performing heat conduction analysis based on the initialized near-field dynamics model includes: The anisotropic heat flux scalar state function is derived using the equivalent thermal potential energy density. The scalar state function of heat flux for anisotropic heat transfer is: ; In the formula, and It is the thermal conductivity along the first principal direction and the second principal direction; m 0 is the volume-weighted factor for the isotropic portion of the peri-field dynamics. m 1 is the volume-weighted component of the peri-field dynamics along the principal direction. m 2 is the volume-weighted quantity along the principal direction of the near-field dynamics. It is the influence function of the isotropic part. It is a partial influence function along the main direction. It is a two-part influence function along the main direction. It is the temperature difference between material points. For matter points, It is the current time; The weighted volume corresponding to the equivalent isotropic part and the principal direction enhancement part m Represented as: ; In the formula, For bond length, It is an integral symbol. L 1 and L 2 represents the effective range of the reinforcing bond along the first and second principal directions, respectively. It refers to the near-field range.

[0008] Preferably, in step three, the calculated temperature field is introduced into the force density function through thermal expansion correction, and a quasi-static solution is performed using the ADR method. The method for calculating the force field deformation includes: Introducing the thermal expansion effect caused by anisotropic heat transfer into the force density scalar state function of the governing equation. In the equation, the corrected force density scalar state function is expressed as: ; In the formula, , , and These are the stiffness matrix components of the elastic parameters. It is the volume expansion amount. The elongation of the bond; The thermal expansion correction term is expressed as: ; In the formula, It is a two-dimensional volumetric thermal expansion correction term. It is the bond elongation caused by thermal expansion. and Bond elongation along the principal direction caused by thermal expansion. and These are the coefficients of thermal expansion along the principal direction and perpendicular to the principal direction. It is the change in temperature of a point in matter. For key The angle between the main direction and the main direction.

[0009] Preferably, in step four, the method for determining the state of near-field dynamic bonds based on force field deformation and using the critical elongation-based bond breakage failure criterion to trace the crack propagation path includes: By incorporating the thermal expansion correction for bond elongation into the function for judging bond damage, a corrected bond damage function is obtained. Based on the modified bond damage function, the bond state is determined using the bond breakage criterion based on critical elongation. Based on the state of the key, local damage is defined for node variables, thereby tracing the crack propagation path.

[0010] The present invention also provides a numerical simulation prediction system for thermo-mechanical coupling fracture analysis of anisotropic rock masses. The system is used to implement the aforementioned method and includes: an initialization module, an analysis module, a calculation module, and a tracking module. The initialization module is used to construct a peridynamic model, input specific parameters of material, geometry and peridynamics, identify and calibrate the principal direction angle of the material, and use the angle tolerance to identify the reinforcing bonds along the principal direction, as well as the isotropic peridynamic bonds; The analysis module is used to perform heat conduction analysis based on the initialized near-field dynamics model; The calculation module is used to introduce the calculated temperature field into the force density function through thermal expansion correction, and use the ADR method to perform quasi-static solution to calculate the force field deformation. The tracking module is used to determine the state of near-field dynamic bonds based on force field deformation and the critical elongation rate bond breakage failure criterion, thereby tracking the crack propagation path.

[0011] Preferably, in the initialization module, the identification of anisotropic bonds is as follows: apart from isotropic basic bonds, when the angle between the bond direction of the connecting material point and the main direction of the rock mass or the direction perpendicular to the main direction is within the tolerance range, the bond is defined as a reinforcing bond along the main direction or a reinforcing bond along the direction perpendicular to the main direction, respectively, thus completing the model direction bond identification initialization.

[0012] Preferably, in the analysis module, the process of performing heat conduction analysis based on the initialized near-field dynamics model includes: The anisotropic heat flux scalar state function is derived using the equivalent thermal potential energy density. The scalar state function of heat flux for anisotropic heat transfer is: ; In the formula, and It is the thermal conductivity along the first principal direction and the second principal direction; m 0 is the volume-weighted factor for the isotropic portion of the peri-field dynamics. m 1 is the volume-weighted component of the peri-field dynamics along the principal direction. m 2 is the volume-weighted quantity along the principal direction of the near-field dynamics. It is the influence function of the isotropic part. It is a partial influence function along the main direction. It is a two-part influence function along the main direction. It is the temperature difference between material points. For matter points, It is the current time; The weighted volume corresponding to the equivalent isotropic part and the principal direction enhancement part m Represented as: ; In the formula, For bond length, It is an integral symbol. L 1 and L 2 represents the effective range of the reinforcing bond along the first and second principal directions, respectively. It refers to the near-field range.

[0013] Preferably, in the calculation module, the calculated temperature field is introduced into the force density function through thermal expansion correction, and a quasi-static solution is performed using the ADR method. The process of calculating the force field deformation includes: Introducing the thermal expansion effect caused by anisotropic heat transfer into the force density scalar state function of the governing equation. In the equation, the corrected force density scalar state function is expressed as: ; In the formula, , , and These are the stiffness matrix components of the elastic parameters. It is the volume expansion amount. The elongation of the bond; The thermal expansion correction term is expressed as: ; In the formula, It is a two-dimensional volumetric thermal expansion correction term. It is the bond elongation caused by thermal expansion. and Bond elongation along the principal direction caused by thermal expansion. and These are the coefficients of thermal expansion along the principal direction and perpendicular to the principal direction. It is the change in temperature of a point in matter. For key The angle between the main direction and the main direction.

[0014] Preferably, in the tracking module, the process of determining the state of near-field dynamic bonds based on force field deformation and using the critical elongation-based bond breakage failure criterion to track the crack propagation path includes: By incorporating the thermal expansion correction for bond elongation into the function for judging bond damage, a corrected bond damage function is obtained. Based on the modified bond damage function, the bond state is determined using the bond breakage criterion based on critical elongation. Based on the state of the key, local damage is defined for node variables, thereby tracing the crack propagation path.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The near-field dynamics used in this invention are based on the theory of nonlocality, which transforms the traditional differential equation of motion into an integral equation, thereby avoiding the stress singularity in the discontinuous region of continuous medium mechanics, and has more advantages in analyzing problems such as fracture damage.

[0016] (2) Traditional near-field dynamic orthogonal anisotropic heat conduction models impose rigid restrictions on the range and ratio of heat conduction coefficients in the two principal directions of the rock mass due to limitations in the derivation method. The principal direction enhanced near-field dynamic heat conduction model proposed in this invention completely eliminates this restriction through the construction of thermal potential of fractional bonds and parameter derivation, and can be adapted to the thermal conductivity of rock masses with any degree of anisotropy.

[0017] (3) The near-field dynamic thermo-coupling damage model used in this invention realizes the meshless and efficient simulation of the entire process of crack initiation and propagation in anisotropic rock mass under high temperature thermal shock environment. It reveals the mechanism of crack propagation path caused by the thermo-coupling anisotropy of rock mass and can provide numerical simulation tools and theoretical support for the prevention and control of thermal fracture disasters in deep underground rock mass engineering, geothermal development and other scenarios. Attached Figure Description

[0018] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the three types of bonds in the orthogonal anisotropic near-field dynamics model in an embodiment of the present invention; Figure 2 This is a flowchart of the thermo-coupling fracture analysis of anisotropic materials in an embodiment of the present invention; Figure 3 This is a schematic diagram of the geometric model and boundary conditions for the thermodynamic analysis of orthogonal anisotropic rock masses in an embodiment of the present invention; Figure 4 For different time periods in the embodiments of the present invention x Schematic diagram of instantaneous temperature distribution on the shaft; Figure 5 For different time periods in the embodiments of the present invention x Schematic diagram of horizontal displacement distribution of the shaft; Figure 6 Here are contour maps of horizontal displacement at different times in an embodiment of the present invention: (a) t= 300 s (b) t= 900 s(c) t= 3000 s; Figure 7 This is a schematic diagram of the geometric model and boundary conditions for thermal fracturing analysis of orthogonal anisotropic rock samples in an embodiment of the present invention; Figure 8The following diagrams show the thermal fracture results in orthotropic rock samples under different bedding directions and high-temperature conditions in this embodiment of the invention: (a) crack path; (b) temperature distribution. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] Example 1 This invention provides a numerical simulation prediction method for thermo-mechanical coupled fracture analysis of anisotropic rock masses. It proposes a thermo-mechanical coupled anisotropic damage model based on conventional near-field dynamics (OSBPD), simultaneously considering the anisotropy of heat conduction and force field deformation. The method quantitatively analyzes the fracture initiation and propagation of rock slabs with singular defects under temperature variations. The specific steps are as follows: Step 1: Initialize the model. Create a peridynamic model based on the actual requirements, inputting specific parameters for materials, geometry, and peridynamics. Identify and calibrate the principal direction angles of the material, and use angle tolerances to identify reinforcing bonds along the principal directions, as well as isotropic peridynamic bonds; Identification of anisotropic bonds in step one. In addition to isotropic basic bonds, when the angle between the bond direction of the connecting material point and the principal direction of the rock mass or the direction perpendicular to the principal direction is within the tolerance range, the bond is defined as a reinforcing bond along the principal direction or a reinforcing bond perpendicular to the principal direction, respectively, thus completing the initialization of model direction bond identification.

[0023] Specifically: First, the model is initialized to determine material, geometric, and near-field dynamic parameters. Due to the innovative introduction of a principal direction enhancement method, bond classification is necessary during the preparation phase. By introducing an angular tolerance that allows for mesh deviation (preset to 5°), bonds coinciding with the first principal direction (parallel to the bedding plane) and the second principal direction (perpendicular to the bedding plane) of the rock mass are selected and labeled as first principal direction enhancement bonds, second principal direction enhancement bonds, and the initially existing isotropic bonds, for a total of three types of bonds. A detailed illustration is shown below. Figure 1 As shown.

[0024] Step two, heat conduction analysis. The heat transfer model uses the conventional near-field dynamics heat transfer governing equations to realize transient heat conduction. The near-field dynamics model discretizes the continuous medium into an array of material points and utilizes the nonlocal bonds of these material points within the near-field range to simulate the interactions within the material, thereby achieving the synchronous transfer and coupling of force and heat. Material points The numerical model of the heat transfer control equation is expressed as follows: In the formula, , and They are matter points The density, specific heat capacity, and first derivative of temperature; yes scalar state function of heat flux density; It is the current time; i It is the index subscript of the target material point; j It is the target material point i The index subscripts of neighboring material points within the near field range; It is the nearest matter point in the near field. j Volume; It is a heat source.

[0025] By applying temperature boundary conditions and heat sources, and using explicit time integration to update the transient temperature field of each material point, the rapid thermal propagation characteristics of heat along the main direction of the rock mass are captured.

[0026] Specifically: Based on the model initialized in step one, heat conduction analysis is performed. A temperature load is applied, and the temperature field distribution of the model is obtained through near-field dynamics numerical solution. Within the near-field dynamics framework, heat exchange is driven by a heat flux scalar state function.

[0027] The anisotropic heat flux scalar state function is derived using the equivalent thermal potential energy density. The scalar state function of heat flux for anisotropic heat transfer is as follows: In the formula, and It is the thermal conductivity along the first principal direction and the second principal direction; m 0 is the volume-weighted factor for the isotropic portion of the peri-field dynamics. m 1 is the volume-weighted component of the peri-field dynamics along the principal direction. m 2 is the volume-weighted quantity along the principal direction of the near-field dynamics. It is the influence function of the isotropic part. It is a partial influence function along the main direction. It is a two-part influence function along the main direction. It is the temperature difference between points of matter.

[0028] The weighted volume corresponding to the equivalent isotropic part and the principal direction enhancement part m Represented as: In the formula, For bond length, It is an integral symbol. L 1 and L 2 represents the effective range of the reinforcing bond along the first and second principal directions, respectively. It refers to the near-field range.

[0029] Temperature conduction along the three bonds can be expressed in terms of temperature difference as follows: In the formula, , and These are the temperature differences between the two material points at the ends of an isotropic bond, a bond reinforced along the first principal direction, and a bond reinforced along the second principal direction, respectively. and It is the lower edge of the material points at both ends of the bond in the global coordinate system. x and y The relative coordinate difference along the axis. b and c This represents the temperature gradient components of the linear temperature field along the x-axis and y-axis in the global coordinate system.

[0030] Step 3, thermo-mechanical coupling analysis stage. The force field deformation is calculated using the conventional peri-field dynamics control equations, and its numerical model can be expressed as: In the formula, For matter points The second derivative of the displacement is the acceleration. For matter points The near-field range, For matter points Force density function Scalar state.

[0031] The temperature field variation is introduced into the mechanical constitutive model, and the force density function is modified by incorporating the direction-dependent thermal expansion effect. The mechanical deformation and displacement of the nodes are updated using the Adaptive Dynamic Relaxation (ADR) method.

[0032] Specifically: The thermal expansion effect caused by anisotropic heat transfer is introduced into the force density scalar state function of the governing equation. The corrected force density scalar state function is expressed as: In the formula, , , and These are the stiffness matrix components of the elastic parameters. It is the volume expansion amount. This represents the elongation of the bond.

[0033] The thermal expansion correction term can be expressed as: In the formula, It is a two-dimensional volumetric thermal expansion correction term. It is the bond elongation caused by thermal expansion. and Bond elongation along the principal direction caused by thermal expansion. It is the change in temperature of a point in matter.

[0034] Step four, fracture propagation analysis stage. The near-field dynamic bond state is determined using the critical elongation failure criterion. The thermal expansion-corrected bond elongation is incorporated into the function for determining bond damage; the corrected bond damage function can be expressed as: In the formula, for Time button elongation, No. i Critical elongation of class bonds (corresponding to isotropic bonds, first principal direction reinforcing bonds, and second principal direction reinforcing bonds), and These are the coefficients of thermal expansion along the principal direction and perpendicular to the principal direction. For key The angle between the main direction and the main direction.

[0035] For different types of bonds in anisotropic materials, when their elongation exceeds the corresponding critical elongation, the function value for judging bond damage changes from 1 to 0, corresponding to bond breakage, and then the crack propagation path is simulated.

[0036] Specifically: The bond state is determined using a bond-breaking criterion based on critical elongation. Critical elongation. It can be represented as: In the formula, and These represent the critical energy release rates of orthogonal anisotropic materials when the crack surface is perpendicular to the first principal direction and the second principal direction, respectively. , , and These are near-field dynamic elastic material parameters. , , and These are parameters related to the near-field dynamics influence function.

[0037] To better visualize macroscopic cracks and thus trace their propagation paths, nodal variables are used to analyze local damage. Defined as: Local damage to nodal variables This reflects the proportion of the volume of the broken bonds connected to the node to the total volume of the node's near-field region: when At that time, the node had no broken keys; The bond connected to that node breaks completely. This parameter... This allows for macroscopic observation of the damage level at each node, thereby tracing the crack propagation path. The specific numerical procedure is as follows: Figure 2 As shown.

[0038] In summary, this method first employs peri-field dynamics, which, based on nonlocal theory, transforms traditional partial differential equations of motion into integral equations, thus avoiding the differential singularity of continuum mechanics when dealing with discontinuities such as cracks. Addressing the complexity of thermally induced fracture analysis in deep underground engineering due to the anisotropic material properties of rock masses, traditional numerical models struggle to systematically and accurately characterize their direction-dependent behavior. Therefore, a novel thermo-mechanically coupled peri-field dynamics framework is proposed. This model derives anisotropic heat conduction equations by introducing a principal direction enhancement method, incorporates direction-dependent thermal expansion effects into the mechanical constitutive relation, and adopts a bond-breaking failure criterion based on anisotropic critical elongation. This enables dynamic prediction of heat conduction, mechanical deformation, and crack initiation and propagation evolution processes in anisotropic rock masses under thermodynamic conditions.

[0039] Example 2 To verify the accuracy of the numerical model of this invention, this invention provides a case study for thermo-mechanical coupling mechanical analysis of anisotropic rock masses, the specific implementation of which is shown below: Step 1: First, initialize the model, determine the material, geometry and peri-field dynamic parameters, and then identify and classify the bonds according to the principal direction.

[0040] The size of the case model is The bedding dip angle is Shale slabs, such as Figure 3 As shown. Applications are made to the left and right boundaries respectively. T =100℃ TThe temperature boundary is 0℃, with fixed top and bottom boundaries. Material parameters are shown in Table 1. In the numerical model, heat conduction is calculated using explicit integration. For the force field, a quasi-static solution is obtained using the ADR numerical integration method.

[0041] Table 1. Shale Slab Material Parameters Step 2: The temperature field updates over time, accompanied by an update of the force field, simulating mechanical phenomena such as model deformation. To verify the accuracy of the established model, the temperature and displacement curves calculated by the model are compared and analyzed with the calculation results of the finite element method (FEM), using time as the variable, to verify the calculation accuracy and effectiveness of the model.

[0042] Using time as a variable, initial layering perspective The temperature versus displacement curves and contour plots of the case study model are compared with those of the finite element method. Figure 4 , Figure 5 and Figure 6 As shown: Depend on Figure 4 and Figure 5 As shown, the temperature in the model gradually increases with time, and the displacement caused by thermal expansion gradually increases with the increase of heat conduction. The temperature and displacement curves obtained from the near-field dynamics simulation agree well with the finite element results. Figure 6 As shown, the near-field dynamics at different times are basically consistent with the displacement contour plots of the finite element method, verifying the effectiveness of the model in handling thermo-mechanical coupling problems.

[0043] This invention provides a case study for thermo-mechanical coupling fracture analysis of anisotropic rock masses, and the specific implementation operation is as follows: Step 1: First, initialize the model, determine the material, geometry and peri-field dynamic parameters, and then identify and classify the bonds according to the principal direction.

[0044] The geometric dimensions and temperature boundary conditions for thermo-coupled fracture analysis of porous anisotropic rock masses are determined by... Figure 7 Given, where the geometric dimensions are A two-dimensional square rock mass plate with a circular hole radius of [missing information]. The model is fixed around its perimeter and kept at a constant temperature of T=100℃, while a temperature that varies with time is applied at the circular opening. The temperature remains constant after reaching 20℃. Plane stress is considered. The material is an orthotropic elastic material, and its parameters are shown in Table 2. In the near-field dynamics numerical model, heat conduction is calculated using explicit integration. For the force field, the ADR numerical integration method is used for quasi-static solution. The critical elongation criterion in near-field dynamics is used to determine bond breakage damage.

[0045] Table 2 Material parameters of rock mass plate Step 2: The temperature field is updated over time, accompanied by an update of the force field. The critical elongation criterion in near-field dynamics is used to determine the bond breakage damage, and then the local damage value of the nodal variables is calculated to simulate the crack propagation path.

[0046] Figure 8 As shown, for all four bedding orientations, cracks initiate at the hole wall and propagate outwards towards the warmer external region. Rapid cooling of the hole surface leads to significant thermal contraction of the material, generating substantial circumferential tensile deformation around the hole opening, which becomes the primary driving force for crack initiation. and The operating conditions manifested as linear crack propagation along the horizontal and vertical axes, respectively. For... and In the direction of the crack, the crack propagates along the direction collinear with the angle of its respective bedding plane. For and Under these conditions, cracks appear near the top and bottom of the circular hole. And for... and In all operating conditions, the cracks originate near the left and right boundaries of the circular hole. All operating conditions exhibit the characteristic of symmetrical crack propagation from both sides of the hole; this morphology is commonly referred to as the symmetrical biplane crack mode in rock fracture mechanics.

[0047] Example 3 The present invention also provides a numerical simulation prediction system for thermo-mechanical coupling fracture analysis of anisotropic rock masses. The system is used to implement the method described in Embodiment 1. The system includes: an initialization module, an analysis module, a calculation module, and a tracking module. The initialization module is used to build a peridynamic model. It takes the specific parameters of material, geometry and peridynamics as input, identifies and calibrates the principal direction angle of the material, and uses the angle tolerance to identify the reinforcing bonds along the principal direction, as well as the isotropic peridynamic bonds. The analysis module is used to perform heat conduction analysis based on the initialized near-field dynamics model; The calculation module is used to introduce the calculated temperature field into the force density function through thermal expansion correction, and use the ADR method to perform quasi-static solution to calculate the force field deformation. The tracking module is used to determine the state of near-field dynamic bonds based on force field deformation and the critical elongation rate-based bond breakage failure criterion, thereby tracking the crack propagation path.

[0048] In this embodiment, the identification of anisotropic bonds in the initialization module is as follows: apart from isotropic basic bonds, when the angle between the bond direction of the connecting material point and the main direction of the rock mass or the perpendicular direction is within the tolerance range, the bond is defined as an enhanced bond along the main direction or an enhanced bond along the perpendicular direction, respectively, thus completing the model direction bond identification initialization.

[0049] In this embodiment, the process of performing heat conduction analysis based on the initialized near-field dynamics model in the analysis module includes: The anisotropic heat flux scalar state function is derived using the equivalent thermal potential energy density. The scalar state function of heat flux for anisotropic heat transfer is: ; In the formula, and It is the thermal conductivity along the first principal direction and the second principal direction; m 0 is the volume-weighted factor for the isotropic portion of the peri-field dynamics. m 1 is the volume-weighted component of the peri-field dynamics along the principal direction. m 2 is the volume-weighted quantity along the principal direction of the near-field dynamics. It is the influence function of the isotropic part. It is a partial influence function along the main direction. It is a two-part influence function along the main direction. It is the temperature difference between material points. For matter points, It is the current time; The weighted volume corresponding to the equivalent isotropic part and the principal direction enhancement part m Represented as: ; In the formula, For bond length, It is an integral symbol. L 1 and L 2 represents the effective range of the reinforcing bond along the first and second principal directions, respectively. It refers to the near-field range.

[0050] In this embodiment, in the calculation module, the calculated temperature field is introduced into the force density function through thermal expansion correction, and the ADR method is used for quasi-static solution. The process of calculating the force field deformation includes: Introducing the thermal expansion effect caused by anisotropic heat transfer into the force density scalar state function of the governing equation. In the equation, the corrected force density scalar state function is expressed as: ; In the formula, , , and These are the stiffness matrix components of the elastic parameters. It is the volume expansion amount. The elongation of the bond; The thermal expansion correction term is expressed as: ; In the formula, It is a two-dimensional volumetric thermal expansion correction term. It is the bond elongation caused by thermal expansion. and Bond elongation along the principal direction caused by thermal expansion. and These are the coefficients of thermal expansion along the principal direction and perpendicular to the principal direction. It is the change in temperature of a point in matter. For key The angle between the main direction and the main direction.

[0051] In this embodiment, the process of tracking the crack propagation path by determining the state of the near-field dynamic bonds based on the force field deformation and using the critical elongation failure criterion to track the crack propagation path includes: By incorporating the thermal expansion correction for bond elongation into the function for judging bond damage, a corrected bond damage function is obtained. Based on the modified bond damage function, the bond state is determined using the bond breakage criterion based on critical elongation. Based on the state of the key, local damage is defined for node variables, thereby tracing the crack propagation path.

[0052] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A numerical simulation prediction method for thermo-mechanical coupled fracture analysis of anisotropic rock masses, characterized in that, The method includes: Step 1: Construct a peri-field dynamics model by inputting specific parameters of the material, geometry, and peri-field dynamics, identifying and calibrating the principal direction angles of the material, and using the angle tolerance to identify reinforcing bonds along the principal direction, as well as isotropic peri-field dynamic bonds; Step 2: Perform heat conduction analysis based on the initialized near-field dynamics model; Step 3: Introduce the calculated temperature field into the force density function through thermal expansion correction, and use the ADR method to perform a quasi-static solution to calculate the force field deformation; Step 4: Based on the force field deformation, use the critical elongation rate to determine the state of the near-field dynamic bond, thereby tracing the crack propagation path.

2. The method according to claim 1, characterized in that, Identification of anisotropic bonds in step one: In addition to isotropic basic bonds, when the angle between the bond direction of the connecting material point and the main direction of the rock mass or the direction perpendicular to the main direction is within the tolerance range, the bond is defined as a reinforcing bond along the main direction or a reinforcing bond perpendicular to the main direction, respectively, thus completing the initialization of model direction bond identification.

3. The method according to claim 1, characterized in that, In step two, the method for performing heat conduction analysis based on the initialized near-field dynamics model includes: The anisotropic heat flux scalar state function is derived using the equivalent thermal potential energy density. The scalar state function of heat flux for anisotropic heat transfer is: ； In the formula, and It is the thermal conductivity along the first principal direction and the second principal direction; m 0 is the volume-weighted factor for the isotropic portion of the peri-field dynamics. m 1 is the volume-weighted component of the peri-field dynamics along the principal direction. m 2 is the volume-weighted quantity along the principal direction of the peri-field dynamics. It is the influence function of the isotropic part. It is a partial influence function along the main direction. It is a two-part influence function along the main direction. It is the temperature difference between material points. For matter points, It is the current time; The weighted volume corresponding to the equivalent isotropic part and the principal direction enhancement part m Represented as: ； In the formula, For bond length, It is an integral symbol. L 1 and L 2 represents the effective range of the reinforcing bond along the first and second principal directions, respectively. It refers to the near-field range.

4. The method according to claim 3, characterized in that, In step three, the calculated temperature field is introduced into the force density function through thermal expansion correction, and the ADR method is used for quasi-static solution. The methods for calculating the force field deformation include: Introducing the thermal expansion effect caused by anisotropic heat transfer into the force density scalar state function of the governing equation. In the equation, the corrected force density scalar state function is expressed as: ； In the formula, , , and These are the stiffness matrix components of the elastic parameters. It is the volume expansion amount. The elongation of the bond; The thermal expansion correction term is expressed as: ； In the formula, It is a two-dimensional volumetric thermal expansion correction term. It is the bond elongation caused by thermal expansion. and Bond elongation along the principal direction caused by thermal expansion. and These are the coefficients of thermal expansion along the principal direction and perpendicular to the principal direction. It is the change in temperature of a point in matter. For key The angle between the main direction and the main direction.

5. The method according to claim 1, characterized in that, In step four, the method for determining the state of near-field dynamic bonds based on force field deformation and using the critical elongation-based bond breakage failure criterion to trace the crack propagation path includes: By incorporating the thermal expansion correction for bond elongation into the function for judging bond damage, a corrected bond damage function is obtained. Based on the modified bond damage function, the bond state is determined using the bond breakage criterion based on critical elongation. Based on the state of the key, local damage is defined for node variables, thereby tracing the crack propagation path.

6. A numerical simulation and prediction system for thermo-mechanical coupled fracture analysis of anisotropic rock masses, the system being used to implement the method described in any one of claims 1-5, characterized in that, The system includes: an initialization module, an analysis module, a calculation module, and a tracking module; The initialization module is used to construct a peridynamic model, input specific parameters of material, geometry and peridynamics, identify and calibrate the principal direction angle of the material, and use the angle tolerance to identify the reinforcing bonds along the principal direction, as well as the isotropic peridynamic bonds; The analysis module is used to perform heat conduction analysis based on the initialized near-field dynamics model; The calculation module is used to introduce the calculated temperature field into the force density function through thermal expansion correction, and use the ADR method to perform quasi-static solution to calculate the force field deformation. The tracking module is used to determine the state of near-field dynamic bonds based on force field deformation and the critical elongation rate bond breakage failure criterion, thereby tracking the crack propagation path.

7. The system according to claim 6, characterized in that, Anisotropic bond identification in the initialization module: In addition to isotropic basic bonds, when the angle between the bond direction of the connecting material point and the main direction of the rock mass or the perpendicular direction is within the tolerance range, the bond is defined as a reinforcing bond along the main direction or a reinforcing bond perpendicular to the main direction, respectively, thus completing the model direction bond identification initialization.

8. The system according to claim 6, characterized in that, In the analysis module, the process of performing heat conduction analysis based on the initialized near-field dynamics model includes: The anisotropic heat flux scalar state function is derived using the equivalent thermal potential energy density. The scalar state function of heat flux for anisotropic heat transfer is: ； In the formula, and It is the thermal conductivity along the first principal direction and the second principal direction; m 0 is the volume-weighted factor for the isotropic portion of the peri-field dynamics. m 1 is the volume-weighted component of the peri-field dynamics along the principal direction. m 2 is the volume-weighted quantity along the principal direction of the peri-field dynamics. It is the influence function of the isotropic part. It is a partial influence function along the main direction. It is a two-part influence function along the main direction. It is the temperature difference between material points. For matter points, It is the current time; The weighted volume corresponding to the equivalent isotropic part and the principal direction enhancement part m Represented as: ； In the formula, For bond length, It is an integral symbol. L 1 and L 2 represents the effective range of the reinforcing bond along the first and second principal directions, respectively. It refers to the near-field range.

9. The system according to claim 8, characterized in that, In the calculation module, the calculated temperature field is incorporated into the force density function through thermal expansion correction, and a quasi-static solution is performed using the ADR method. The process of calculating the force field deformation includes: Introducing the thermal expansion effect caused by anisotropic heat transfer into the force density scalar state function of the governing equation. In the equation, the corrected force density scalar state function is expressed as: ； In the formula, , , and These are the stiffness matrix components of the elastic parameters. It is the volume expansion amount. The elongation of the bond; The thermal expansion correction term is expressed as: ； In the formula, It is a two-dimensional volumetric thermal expansion correction term. It is the bond elongation caused by thermal expansion. and Bond elongation along the principal direction caused by thermal expansion. and These are the coefficients of thermal expansion along the principal direction and perpendicular to the principal direction. It is the change in temperature of a point in matter. For key The angle between the main direction and the main direction.

10. The system according to claim 6, characterized in that, In the tracking module, the process of determining the state of near-field dynamic bonds based on force field deformation and using the critical elongation-based bond breakage failure criterion to track the crack propagation path includes: By incorporating the thermal expansion correction for bond elongation into the function for judging bond damage, a corrected bond damage function is obtained. Based on the modified bond damage function, the bond state is determined using the bond breakage criterion based on critical elongation. Based on the state of the key, local damage is defined for node variables, thereby tracing the crack propagation path.

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