A numerical simulation method and system based on coupling of rock mass crack expansion and seepage

Abstract

The present invention proposes a numerical simulation method and system based on the coupling of rock fracture expansion and seepage, which belongs to the field of rock mechanics. Rock is regarded as a collection of particles and their mechanical contact with each other, and a triangulated network is constructed based on the center of each particle; according to the geometric characteristics of the triangulated network, a seepage pipe network containing the interior and the periphery is constructed, and the network nodes and boundary nodes are determined; the permeability coefficient is calculated according to the position of the particles on both sides of the pipe, and the pipes that are not 0 and pass through and connect the boundary nodes are used as passage pipes to form a through seepage channel and fracture network; a flow conservation equation group is constructed based on the network nodes, and the Jacobi iteration method is used to solve the pore pressure, calculate the fracture pressure, and apply it to the model to realize the coupling of stress field and seepage field. The present invention gives full play to the advantages of particle discrete element method in calculating rock fracture expansion and pipeline network method in calculating fracture seepage, and realizes the accurate simulation of rock fracture initiation and expansion, seepage channel identification and seepage field calculation.

Description

Technical Field

[0001] The present invention relates to the technical field of rock mechanics, and in particular to a numerical simulation method and system based on coupling of rock mass fracture expansion and seepage. Background Art

[0002] Rock fracture propagation, fracture seepage, and their coupling are common problems in water conservancy and hydropower engineering, slope engineering, tunneling, mining, and underground energy storage. Existing numerical simulation methods have several shortcomings in describing the coupling of rock fracture propagation and seepage. Specifically, they struggle to accurately identify the dynamic seepage pathways during rock fracture propagation. Furthermore, they cannot accurately represent the actual state of fracture propagation driven by fluid pressure. These shortcomings severely hinder the accurate analysis and effective resolution of related engineering problems. Summary of the Invention

[0003] In order to solve the above problems, the present invention proposes a numerical simulation method and system based on the coupling of rock fracture expansion and seepage, which fully leverages the advantages of the particle discrete element method (DEM) in calculating rock fracture expansion and the pipeline network method (PNM) in calculating fracture seepage. It realizes the functions of simulating the rock fracture expansion process, dynamically identifying seepage channels, calculating the seepage field, and fluid pressure-driven fracture expansion, thus achieving accurate simulation of rock fracture initiation and expansion, seepage channel identification, and seepage field calculation.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] In a first aspect, the present invention provides a numerical simulation method based on the coupling of rock mass fracture expansion and seepage, comprising:

[0006] Rock is considered as a collection of particles and their mechanical contacts, and a Delaunay triangulation is constructed based on the center of each particle.

[0007] According to the geometric characteristics of triangles in the Delaunay triangulation, a pipeline network including internal seepage pipelines and external seepage pipelines of the model is established; the endpoints of the internal seepage pipelines of the model are pipeline network nodes, and the endpoints extending from the external seepage pipelines of the model are pipeline network boundary nodes;

[0008] Calculate the pipeline permeability coefficient based on the relative positions of particles on both sides of the seepage pipeline;

[0009] The seepage pipes with non-zero permeability coefficients are regarded as access pipes. If the access pipes are connected and connected to the boundary nodes of the pipe network, a through-seepage channel is formed. The fracture network is obtained based on the through-seepage channel.

[0010] Obtain the pipeline network nodes in the fracture network to construct the flow conservation equations, and use the Jacobi iteration method to solve the node pore pressure;

[0011] The fracture pressure is calculated based on the average pore pressure of two pipeline network nodes, and the fracture pressure is applied to the fracture network to achieve stress field-seepage field coupling.

[0012] Preferably, the method establishes a pipeline network including internal seepage pipelines and external seepage pipelines of the model based on the geometric characteristics of triangles in the Delaunay triangulation; specifically includes: connecting the centroids of any two adjacent triangles inside the Delaunay triangulation to form an internal seepage pipeline of the model; and connecting the centroids of the triangles and the midpoints of the boundary edges at the outer boundary of the Delaunay triangulation, and extending the same distance in this direction to form an external seepage pipeline of the model.

[0013] Preferably, the calculation of the pipeline permeability coefficient according to the relative positions of particles on both sides of the seepage pipeline specifically includes:

[0014] Assume that the pipe permeability coefficient and its corresponding particle spacing satisfy the cubic law;

[0015] ;

[0016] in, is the pipeline permeability coefficient; is the correction factor; is the particle spacing, are the distances between two particles in the x and y directions respectively; is the acceleration due to gravity; is the kinematic viscosity of the fluid.

[0017] Preferably, in the entire pipeline network system, if all the seepage pipelines directly connected to the pipeline determined to be the passage pipeline are the passage pipelines, it is determined that the passage pipelines are connected.

[0018] Preferably, there is fissure seepage in the through seepage channel, which is used to dynamically identify rock mass seepage channels based on fissure distribution characteristics.

[0019] Preferably, the step of obtaining pipeline network nodes in the fracture network to construct a flow conservation equation group and solving the node pore pressure using the Jacobi iteration method specifically includes:

[0020] According to the law of flow conservation, the flow conservation equation is constructed for the pipeline network nodes in the fracture network;

[0021] All flow conservation equations in the fracture network are combined to form a flow conservation equation system;

[0022] Based on the flow conservation equations, the relationship between the pore pressure at the pipeline network node and the pore pressure at the three connected nodes is obtained, and the pore pressure is solved using the Jacobi iteration method:

[0023] ;

[0024] in, is the node hole pressure, For the The distance between the particles corresponding to the pipes connected to the node, For the The pore pressure of the nodes connected to this node; For the The length of the pipe connected to the node.

[0025] Preferably, the method comprises calculating the fracture pressure based on the average pore pressure of two pipeline network nodes, applying the fracture pressure to the fracture network, calculating the fracture expansion process, and updating the particle displacement and permeability coefficient to realize the stress field-seepage field coupling; specifically comprising:

[0026] The fracture pressure is applied to the average length of the pipe in the discrete element model of the particle, and the fracture expansion process driven by the fracture fluid pressure is numerically calculated to achieve the simulation of fracture expansion under the action of fluid pressure, that is, the coupling of flow field to force field.

[0027] Based on the crack expansion simulation results and particle displacement, the pipeline permeability coefficient is calculated and updated to simulate the pipeline permeability coefficient along with the crack expansion process, that is, the coupling of the force field to the flow field.

[0028] In a second aspect, the present invention provides a numerical simulation system based on the coupling of rock fracture expansion and seepage, comprising:

[0029] The particle modeling module is configured to treat the rock as a collection of particles and their mechanical contacts, and construct a Delaunay triangulation based on the center of each particle;

[0030] The pipeline network modeling module is configured to establish a pipeline network including internal seepage pipelines and external seepage pipelines according to the geometric characteristics of triangles in the Delaunay triangulation network; the endpoints of the internal seepage pipelines are pipeline network nodes, and the endpoints of the external seepage pipelines are pipeline network boundary nodes;

[0031] A permeability coefficient calculation module is configured to calculate the permeability coefficient of the pipeline based on the relative positions of particles on both sides of the seepage pipeline;

[0032] A fracture network establishment module is configured to treat seepage pipes with a non-zero permeability coefficient as access pipes. If the access pipes are connected and connected to the boundary nodes of the pipe network, a through-seepage channel is formed; and a fracture network is obtained based on the through-seepage channel.

[0033] The pore pressure calculation module is configured to obtain the pipeline network nodes in the fracture network to construct the flow conservation equations and solve the node pore pressure using the Jacobi iteration method;

[0034] The coupled simulation module is configured to calculate the fracture pressure based on the average pore pressure of two pipeline network nodes, apply the fracture pressure to the fracture network, and realize the stress field-seepage field coupling.

[0035] In a third aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of a numerical simulation method based on the coupling of rock fracture expansion and seepage described in the first aspect.

[0036] In a fourth aspect, the present invention provides a computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, the steps of the numerical simulation method based on the coupling of rock fracture expansion and seepage described in the first aspect are implemented.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] The present invention regards rock as a collection of particle models and contacts, constructs a Delaunay triangulation based on the center of the particle node circle, and then establishes a seepage pipeline network, accurately calculates the pipeline permeability coefficient, and finds the through-seepage channel to form a fracture network. Among them, the pipeline network is reasonably constructed based on the triangle characteristics in the Delaunay triangulation, the permeability coefficient is calculated considering the position of particles on both sides of the seepage pipeline, the Jacobi iteration method is used to solve the node pore pressure in the fracture network, and the fracture pressure is calculated and applied by the average value of the pore pressure to achieve the coupling of the stress field and the seepage field. It can dynamically identify the seepage channel, solve the problem that the existing method is difficult to dynamically and accurately identify the seepage channel during the fracture expansion process, and can also accurately present the situation of fluid pressure driving the fracture expansion, overcoming the shortcomings of the existing simulation method in describing the coupling problem, and providing a more accurate and effective analysis tool for water conservancy, slopes, tunnels, mines and underground energy storage projects. It provides a new idea for the simulation of seepage-stress coupling during the expansion of rock cracks, and develops and promotes the numerical simulation technology methods in the field of rock mechanics. It can be used in the fields of sealing analysis of underground crude oil storage and underground gas storage, stability analysis of fractured rock slopes under rainfall infiltration conditions, stability analysis of rock tunnels and water inrush calculation.

[0039] Advantages of additional aspects of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their description are used to explain the present invention but do not constitute a limitation of the present invention.

[0041] Figure 1 A main flow chart of a numerical simulation method based on the coupling of rock fracture expansion and seepage provided by an embodiment of the present invention;

[0042] Figure 2 A schematic flow chart of a numerical simulation method based on the coupling of rock fracture expansion and seepage provided by an embodiment of the present invention;

[0043] Figure 3 A schematic diagram of a unified geometric model of a particle model and a pipeline network model provided in an embodiment of the present invention;

[0044] Figure 4 A schematic diagram of calculating the pipeline permeability coefficient provided by an embodiment of the present invention;

[0045] Figure 5 Schematic diagram of mechanical failure provided by an embodiment of the present invention; wherein (a) is a crack distribution diagram after rock failure; (b) is a particle radial displacement diagram after rock failure;

[0046] Figure 6 The seepage situation after rock failure provided by the embodiment of the present invention; wherein, (a) is the head distribution diagram after rock failure; (b) is the flow velocity distribution diagram after rock failure. DETAILED DESCRIPTION

[0047] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0048] Numerical simulations of rock fracture propagation are fundamental, as fracture expansion alters the rock mass structure, influencing the formation and evolution of seepage channels. Therefore, dynamic identification of seepage channels is closely related to this process. This dynamic identification of seepage channels provides crucial structural information for seepage field calculations. Only by accurately identifying seepage channels can effective seepage field calculations be performed. Fluid pressure-driven fracture propagation, on the other hand, demonstrates the influence of the seepage field (fluid pressure being a key parameter in the seepage field) on fracture propagation. Changes in the seepage field lead to changes in fluid pressure, which in turn drives further fracture expansion.

[0049] As can be seen, in actual rock mass engineering, crack expansion changes the permeability of the rock mass, thereby affecting seepage; the fluid pressure generated by seepage, in turn, affects crack expansion. The two interact and influence each other, forming a coupled relationship. The numerical simulation method provided by this invention aims to accurately simulate this coupled process, that is, to simultaneously consider the mutual influence of crack expansion and seepage, so as to more realistically reflect the mechanical and hydraulic properties of rock masses in actual engineering.

[0050] Example 1

[0051] like Figure 1 As shown, this embodiment discloses a numerical simulation method based on the coupling of rock fracture expansion and seepage, comprising the following steps:

[0052] S1: Rock is considered to be a collection of particles and their mechanical contacts, and a Delaunay triangulation is constructed based on the center of each particle.

[0053] S2: Based on the geometric characteristics of triangles in the Delaunay triangulation, a pipeline network is established, including seepage pipelines inside the model and seepage pipelines outside the model; the endpoints of the seepage pipelines inside the model are pipeline network nodes, and the endpoints extending from the seepage pipelines outside the model are pipeline network boundary nodes;

[0054] S3: Calculate the pipeline permeability coefficient based on the relative positions of particles on both sides of the seepage pipeline;

[0055] S4: The seepage pipes with a non-zero permeability coefficient are regarded as access pipes. If the access pipes are connected and connected to the boundary nodes of the pipe network, a through-seepage channel is formed; a fracture network is obtained based on the through-seepage channel.

[0056] S5: Obtain the pipeline network nodes in the fracture network to construct the flow conservation equations, and use the Jacobi iteration method to solve the node pore pressure;

[0057] S6: Calculate the fracture pressure based on the average pore pressure of the two pipeline network nodes, apply the fracture pressure to the fracture network, and realize the stress field-seepage field coupling.

[0058] Next, combine Figure 2 , a numerical simulation method based on the coupling of rock fracture expansion and seepage disclosed in this embodiment is described in detail.

[0059] In S1, this embodiment preferably uses the commercial software PFC based on particle discrete element (DEM) 2D Secondary development is carried out in the development environment. Figure 3 As shown in the figure, the rock mass is regarded as a collection of particles and their mutual mechanical contacts. The center of the particle circle (sphere) of the particle model is used as the node, and the Delaunay triangulation is constructed by point-by-point insertion method.

[0060] It should be understood that those skilled in the art can select other software for development as needed.

[0061] The Delaunay triangulation is a collection of connected but non-overlapping triangles whose circumscribed circles do not contain any other points in the domain. The subsequent seepage pipe network constructed based on this triangulation can accurately track changes in the internal structure of the rock mass, providing a precise geometric framework for the dynamic identification of seepage channels.

[0062] In S2, a pipeline network model is constructed. For common edges within the triangulated network, the centroids of two adjacent triangles are connected to form seepage pipes, which describe the potential seepage between particles at both ends of the common edge. For the periphery of the triangulated network, seepage pipes are formed by connecting the centroids of the triangles and the midpoints of the edges, extending them the same distance in this direction. These seepage pipes describe the potential seepage between particles at both ends of the edges. The extended endpoints of the seepage pipes serve as the pipeline network boundaries, where pore pressure boundary conditions are applied. A unified geometric model of the particle model and the pipeline network model is established.

[0063] In this embodiment, a pipeline network model is constructed based on the Delaunay triangulation. By connecting the centroids of adjacent triangles to form internal seepage pipelines, and constructing extended seepage pipelines outside the triangulation, the potential seepage paths inside and at the boundaries of the rock mass are fully covered.

[0064] This construction method establishes a connection between the pipeline permeability coefficient and particle displacement. When the expansion of rock cracks causes the particles to move, the pipeline permeability coefficient can be updated synchronously.

[0065] For example, the formation of new fractures can cause significant displacement of particles on either side of the fracture, increasing the corresponding pipe's seepage coefficient and thus forming new pathways. Furthermore, the well-defined pipe network nodes and boundary nodes provide a clear structure for applying boundary conditions and performing flow calculations. This allows the formation and evolution of seepage channels to be accurately captured during simulations, effectively resolving the difficulty of traditional methods in dynamically tracking changes in seepage channels.

[0066] In S3, the permeability coefficient of the pipeline is defined as the distance between the particles on both sides, and a quantitative relationship between the particle position (displacement) characteristics and the permeability coefficient of the pipeline is established, such as Figure 4 Assume that the pipe permeability coefficient and the corresponding particle spacing satisfy the cubic law:

[0067]

[0068] Where, is the pipeline permeability coefficient; is the correction factor; is the particle spacing, are the distances between two particles in the x and y directions respectively; is the acceleration due to gravity; is the kinematic viscosity of the fluid.

[0069] Traditional methods typically use a fixed permeability coefficient, which fails to reflect the dynamic changes in seepage characteristics of rock mass during stress and deformation. However, this embodiment establishes a quantitative relationship between particle position (displacement) characteristics and the pipe permeability coefficient. When the rock mass is subjected to stress, causing the interparticle spacing to change, the permeability coefficient dynamically adjusts accordingly. Because changes in the permeability coefficient directly affect the fluid's flow resistance and flow distribution, this dynamic adjustment mechanism enables more accurate simulation of fluid flow in rock mass when simulating fluid pressure-driven fracture expansion.

[0070] In S4, the pipeline network is searched for pipelines with non-zero permeability coefficients, which are considered access pipelines. When access pipelines are connected to boundary nodes of the pipeline network, they form through-flow channels, generating fracture seepage, enabling dynamic identification of rock mass seepage channels based on fracture distribution characteristics. Dynamic identification involves identifying the changing process of fractures to obtain a fracture network.

[0071] This embodiment achieves dynamic and accurate identification of rock seepage channels by screening the passage pipes based on the pipe permeability coefficient and determining the through seepage channels and fracture networks. Since the pipe permeability coefficient is dynamically related to the relative position of the particles, when the rock fractures expand or close, the permeability coefficient will change accordingly, resulting in changes in the distribution and connectivity of the passage pipes. This dynamic identification method based on actual physical processes can accurately capture the formation and evolution of seepage channels in the rock mass under different stress stages and deformation states. Compared with traditional methods, it can more realistically reflect the fracture development and seepage laws inside the rock mass, provide an accurate model basis for the subsequent simulation of fluid pressure-driven fracture expansion, and avoid simulation errors caused by the inability to accurately identify seepage channels.

[0072] In S5, for each non-boundary node in the fracture network, three pipes converge at that point. Based on the law of flow conservation (i.e., the outflow and inflow of water from a node are equal), a flow conservation equation is established for that point, with the unknowns being the pore pressures at that node and its connected neighbors. The equations for each node in the seepage pathway are combined to form a system of equations with the node pore pressures as the unknowns.

[0073] According to the law of conservation of flow, the relationship between the pore pressure of each non-boundary node and the pore pressure of the three connected nodes is shown in Equation 2. Therefore, the Jacobi iteration method is used to solve the pore pressure equations, and the calculation error is taken as .

[0074]

[0075] Where, is the node hole pressure, For the The distance between the particles corresponding to the pipes connected to the node, For the The pore pressure of the nodes connected to this node; For the The length of the pipe connected to the node.

[0076] This example constructs a set of flow conservation equations based on the pipe network nodes within the fracture network, fully accounting for the flow relationships between nodes within the fracture network and ensuring the accuracy of the pore pressure calculations. The Jacobi iteration method, with its rapid convergence and excellent computational stability, can quickly obtain highly accurate node pore pressure solutions. Accurate pore pressure calculations provide critical data for subsequent calculations of fracture pressures and simulations of stress-seepage coupling. This allows the simulation process to more realistically reflect the distribution and transmission of fluid pressure within the rock mass, thereby more accurately simulating the actual process of fluid pressure-driven fracture expansion.

[0077] In S6, the fracture pressure is calculated based on the average pore pressure of the two pipeline network nodes, the fracture pressure is applied to the fracture network, the fracture expansion process is calculated, and the particle displacement and permeability coefficient are updated to achieve stress field-seepage field coupling. Specifically, it includes:

[0078] For each pipeline, the average pore pressure of its two nodes is taken to calculate the fracture pressure, and the average pressure is applied to the particle model along the pipeline length to promote fracture expansion. The fracture fluid pressure drives the fracture expansion process by numerical calculation, realizing the simulation of fracture expansion under the action of fluid pressure, that is, coupling the flow field to the force field.

[0079] Based on the crack expansion simulation results and particle displacement, the pipeline permeability coefficient is calculated and updated to simulate the pipeline permeability coefficient along with the crack expansion process, that is, the coupling of the force field to the flow field.

[0080] This example calculates the average pore pressure at two pipeline network nodes to obtain the fracture pressure, and applies this pressure to the discrete element model of the particles in the pipeline. This simulates the process of fluid pressure driving fracture expansion, taking into account the effect of the flow field on the force field. Simultaneously, the particle displacement and permeability coefficient are updated based on the fracture expansion simulation results, achieving feedback from the force field to the flow field. This bidirectional coupling mechanism enables the simulation process to fully consider the interaction between rock fracture expansion and seepage. Through this dynamic coupling process, the mechanical behavior of rock masses under complex stress and seepage conditions can be more accurately simulated.

[0081] The rock mass fracture expansion and seepage coupled simulation method (DEM-PMM) formed in this embodiment is a cyclic dynamic simulation process. Figure 2 As shown, steps S2-S6 are executed cyclically, and the coupling process of rock fracture expansion and seepage is accurately simulated by continuously updating model parameters, identifying seepage channels, calculating pore pressure, and realizing field coupling.

[0082] In order to verify the effect of this embodiment, Figure 5 、 6 As shown in Figure 2, these experimental results are obtained based on the numerical simulation method (DEM-PMM) based on the coupling of rock mass crack expansion and seepage proposed in this embodiment. By using this method, as shown in Figure 2, Figure 5 As shown in a, the distribution of cracks inside the rock after the triaxial compression test under the condition of confining pressure of 2MPa is successfully simulated, and the through cracks are formed after the rock is damaged, and the main form of failure is tension and shear. Figure 5 As shown in b, after rock failure, the particle displacement on both sides of the main crack develops away from the crack, resulting in an increase in the crack width.

[0083] like Figure 6 As shown in a, after the triaxial compression test of rock under confining pressure of 2 MPa, the head distribution during the rock seepage process with a head difference of 30 m is set. In other words, in terms of seepage simulation, it is accurately shown that the rock seepage mainly proceeds along the through cracks to form a seepage channel. Figure 6 b is the flow velocity distribution. The through cracks formed after rock destruction form the main seepage channel, and the larger the crack width, the greater the flow velocity, which reflects the relationship between crack width and flow velocity.

[0084] These simulation results are consistent with existing research, fully verifying the accuracy and reliability of the proposed method in simulating the coupled process of rock fracture propagation and seepage. It not only effectively captures the mechanical behavior and seepage characteristics of rock under complex stress and seepage conditions, but also offers significant advantages over traditional simulation methods in dynamically identifying seepage channels and accurately demonstrating the effects of fluid pressure on fracture propagation. This provides a more scientific and effective approach to analyzing rock fractures in related engineering fields.

[0085] This specific embodiment forms a closed-loop interaction relationship between the functions of rock fracture expansion process simulation, dynamic identification of seepage channels, seepage field calculation, and fluid pressure-driven fracture expansion, which together constitute a comprehensive simulation of the coupling problem of rock fracture expansion and seepage. By breaking through traditional limitations, the coupling process of rock fracture expansion and seepage is accurately captured. By carefully constructing the seepage pipeline network, dynamic and accurate identification of seepage channels is achieved, which makes up for the shortcomings of existing methods in this regard. When simulating fluid pressure-driven fracture expansion, the actual situation is truly restored based on the accurately calculated pore pressure and fracture pressure. This method greatly improves the accuracy and reliability of the simulation, and provides a scientific basis for water conservancy, hydropower, mining and other engineering fields when analyzing rock fracture-related issues, helping to optimize engineering design, reduce construction risks, and ensure engineering safety and stable operation.

[0086] Example 2

[0087] This embodiment provides a numerical simulation system based on the coupling of rock fracture expansion and seepage, including:

[0088] The particle modeling module is configured to treat the rock as a collection of particles and their mechanical contacts, and construct a Delaunay triangulation based on the center of each particle;

[0089] The pipeline network modeling module is configured to establish a pipeline network including internal seepage pipelines and external seepage pipelines according to the geometric characteristics of triangles in the Delaunay triangulation network; the endpoints of the internal seepage pipelines are pipeline network nodes, and the endpoints of the external seepage pipelines are pipeline network boundary nodes;

[0090] A permeability coefficient calculation module is configured to calculate the permeability coefficient of the pipeline based on the relative positions of particles on both sides of the seepage pipeline;

[0091] A fracture network establishment module is configured to treat seepage pipes with a non-zero permeability coefficient as access pipes. If the access pipes are connected and connected to the boundary nodes of the pipe network, a through-seepage channel is formed; and a fracture network is obtained based on the through-seepage channel.

[0092] The pore pressure calculation module is configured to obtain the pipeline network nodes in the fracture network to construct the flow conservation equations and solve the node pore pressure using the Jacobi iteration method;

[0093] The coupled simulation module is configured to calculate the fracture pressure based on the average pore pressure of two pipeline network nodes, apply the fracture pressure to the fracture network, and realize the stress field-seepage field coupling.

[0094] Example 3

[0095] This embodiment provides a computer-readable storage medium having a computer program stored thereon. When the program is executed by a processor, the steps of the numerical simulation method based on the coupling of rock fracture expansion and seepage as described in the first embodiment above are implemented.

[0096] Example 4

[0097] This embodiment provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, the steps of the numerical simulation method based on the coupling of rock fracture expansion and seepage as described in the first embodiment above are implemented.

[0098] The steps or modules involved in Examples 2 to 4 above correspond to those in Example 1. For detailed implementations, please refer to the relevant description of Example 1. The term "computer-readable storage medium" should be understood to mean a single medium or multiple media that includes one or more instruction sets; it should also be understood to include any medium that can store, encode, or carry an instruction set for execution by a processor and cause the processor to perform any method of the present invention.

[0099] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A numerical simulation method based on the coupling of rock mass fracture expansion and seepage, characterized in that: include: Rock is considered as a collection of particles and their mechanical contacts, and a Delaunay triangulation is constructed based on the center of each particle. According to the geometric characteristics of triangles in the Delaunay triangulation, a pipeline network including internal seepage pipelines and external seepage pipelines of the model is established; the endpoints of the internal seepage pipelines of the model are pipeline network nodes, and the endpoints extending from the external seepage pipelines of the model are pipeline network boundary nodes; Calculate the pipeline permeability coefficient based on the relative positions of particles on both sides of the seepage pipeline; Assume that the pipe permeability coefficient and its corresponding particle spacing satisfy the cubic law; ； in, is the pipeline permeability coefficient; is the correction factor; is the particle spacing, are the distances between two particles in the x and y directions respectively; is the acceleration due to gravity; is the kinematic viscosity of the fluid; The permeability coefficient of the pipeline is dynamically related to the relative position of the particles. When the rock mass is subjected to stress and the distance between the particles changes, the permeability coefficient will be dynamically adjusted accordingly. The seepage pipe with a non-zero permeability coefficient is regarded as a passage pipe. If the passage pipe is connected and connected to the boundary node of the pipeline network, a through seepage channel is formed. There is fracture seepage in the through-seepage channel, which is used to dynamically identify the rock mass seepage channel based on the fracture distribution characteristics; The dynamic identification refers to the changing process of identifying cracks; The fracture network is obtained based on the through-flow channels; Obtain the pipeline network nodes in the fracture network to construct the flow conservation equations, and use the Jacobi iteration method to solve the node pore pressure; The fracture pressure is calculated based on the average pore pressure of two pipeline network nodes, and the fracture pressure is applied to the fracture network to achieve stress field-seepage field coupling.

2. The numerical simulation method based on the coupling of rock mass fracture expansion and seepage according to claim 1, characterized in that: The method establishes a pipeline network including internal seepage pipelines and external seepage pipelines of the model based on the geometric characteristics of triangles in the Delaunay triangulation. Specifically, the method includes: connecting the centroids of any two adjacent triangles inside the Delaunay triangulation to form the internal seepage pipeline of the model; and connecting the centroids of the triangles and the midpoints of the boundary edges on the outer boundary of the Delaunay triangulation, and extending the same distance in this direction to form the external seepage pipeline of the model.

3. The numerical simulation method based on the coupling of rock mass fracture expansion and seepage according to claim 1, characterized in that: In the entire pipeline network system, if all the seepage pipes directly connected to the passage pipes identified as passage pipes are passage pipes, then the passage pipes are deemed to be connected.

4. The numerical simulation method based on the coupling of rock mass fracture expansion and seepage according to claim 1, characterized in that: The method of obtaining the pipeline network nodes in the fracture network to construct a flow conservation equation group and solving the node pore pressure using the Jacobi iteration method specifically includes: According to the law of flow conservation, the flow conservation equation is constructed for the pipeline network nodes in the fracture network; All flow conservation equations in the fracture network are combined to form a flow conservation equation system; Based on the flow conservation equations, the relationship between the pore pressure at the pipeline network node and the pore pressure at the three connected nodes is obtained, and the pore pressure is solved using the Jacobi iteration method: ； in, is the node hole pressure, For the The distance between the particles corresponding to the pipes connected to the node, For the The pore pressure of the nodes connected to this node; For the The length of the pipe connected to the node.

5. The numerical simulation method based on the coupling of rock mass fracture expansion and seepage according to claim 1, characterized in that: The method calculates the fracture pressure based on the average pore pressure of two pipeline network nodes, applies the fracture pressure to the fracture network, calculates the fracture expansion process, and updates the particle displacement and permeability coefficient to achieve stress field-seepage field coupling; specifically includes: The fracture pressure is applied to the average length of the pipe in the discrete element model of the particle, and the fracture expansion process driven by the fracture fluid pressure is numerically calculated to achieve the simulation of fracture expansion under the action of fluid pressure, that is, the coupling of flow field to force field. Based on the crack expansion simulation results and particle displacement, the pipeline permeability coefficient is calculated and updated to simulate the pipeline permeability coefficient along with the crack expansion process, that is, the coupling of the force field to the flow field.

6. A numerical simulation system based on the coupling of rock mass fracture expansion and seepage, characterized in that: include: The particle modeling module is configured to treat the rock as a collection of particles and their mechanical contacts, and construct a Delaunay triangulation based on the center of each particle; The pipeline network modeling module is configured to establish a pipeline network including internal seepage pipelines and external seepage pipelines according to the geometric characteristics of triangles in the Delaunay triangulation network; the endpoints of the internal seepage pipelines are pipeline network nodes, and the endpoints of the external seepage pipelines are pipeline network boundary nodes; A permeability coefficient calculation module is configured to calculate the permeability coefficient of the pipeline based on the relative positions of particles on both sides of the seepage pipeline; Assume that the pipe permeability coefficient and its corresponding particle spacing satisfy the cubic law; ； in, is the pipeline permeability coefficient; is the correction factor; is the particle spacing, are the distances between two particles in the x and y directions respectively; is the acceleration due to gravity; is the kinematic viscosity of the fluid; The permeability coefficient of the pipeline is dynamically related to the relative position of the particles. When the rock mass is subjected to stress and the distance between the particles changes, the permeability coefficient will be dynamically adjusted accordingly. The fracture network establishment module is configured to treat a seepage pipe with a non-zero permeability coefficient as a passage pipe. If the passage pipe is connected and connected to a boundary node of the pipe network, a through-seepage channel is formed. There is fracture seepage in the through-seepage channel, which is used to dynamically identify the rock mass seepage channel based on the fracture distribution characteristics; The dynamic identification refers to the changing process of identifying cracks; The fracture network is obtained based on the through-flow channels; The pore pressure calculation module is configured to obtain the pipeline network nodes in the fracture network to construct the flow conservation equations and solve the node pore pressure using the Jacobi iteration method; The coupled simulation module is configured to calculate the fracture pressure based on the average pore pressure of two pipeline network nodes, apply the fracture pressure to the fracture network, and realize the stress field-seepage field coupling.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the numerical simulation method based on the coupling of rock fracture expansion and seepage according to any one of claims 1 to 5 are implemented.

8. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the steps of the numerical simulation method based on the coupling of rock fracture expansion and seepage according to any one of claims 1 to 5 are implemented.

Images