Smooth point interpolation coupled with discrete element method for simulation of deformation of overburden strata during coal mining

Abstract

The application relates to the technical field of data simulation processing, in particular to a smooth point interpolation-discrete element coupling simulation method suitable for coal mining overburden rock deformation, which comprises the following steps: based on a three-dimensional calculation model of a coal mine, firstly, the continuous deformation of the coal mine rock stratum is simulated by using a smooth point interpolation method, units with a deformation parameter greater than or equal to a deformation threshold value in the rock stratum are marked as units to be converted and are converted into rigid discrete blocks, then the region corresponding to the rigid discrete blocks is continuously simulated by using a block discrete element method; the region corresponding to the units with a deformation parameter less than the deformation threshold value is continuously simulated by using the smooth point interpolation method, and the process of the block discrete element simulation and the process of the smooth point interpolation simulation are coupled to dynamically simulate the deformation of the coal mine rock stratum. According to the smooth point interpolation-block discrete element coupling simulation method, the deformation and movement law of the overburden rock under the influence of mining can be analyzed, so that the deformation and damage process of the overburden rock can be accurately predicted.

Description

Technical Field

[0001] This application relates to the field of data simulation and processing technology, and in particular to a smooth point interpolation-discrete element coupled simulation method suitable for coal mining overburden deformation. Background Technology

[0002] In my country's multi-driven energy system, coal has always been a fundamental and primary energy source for ensuring energy supply. In the short term, my country's reliance on coal resources as its main energy source will remain unchanged, and large-scale, high-intensity coal mining will continue for a considerable period. However, underground coal mining disrupts the initial stress balance of the overlying strata, leading to deformation and movement of the overlying strata, which in turn causes surface subsidence. This poses a significant threat to buildings, transportation infrastructure, and pipelines within the mining area, resulting in prominent social, economic, and environmental problems. Therefore, researching and predicting the deformation and movement patterns of overlying strata induced by mining is of great importance. It helps in formulating scientific and rational mining plans, thereby effectively reducing the disasters and losses caused by mining.

[0003] In related technologies, numerical simulation methods are difficult to simulate problems such as overburden deformation, cracking, collapse and compaction induced by mining. Therefore, coupled simulation methods are used to study these problems. For example, continuous and discontinuous problems can be simulated by connecting and fracturing block boundaries. These methods mainly include CDEM (continuous-discontinuous element method) and FDEM (finite-discrete element method). Continuous problems can also be simulated by using finite element method, finite difference method, etc., and discontinuous problems can be simulated by using discrete element method, etc. Data exchange can be performed at the coupling boundary to achieve coupled analysis.

[0004] However, in the relevant technologies, existing numerical simulation methods are either limited by mesh distortion and low computational efficiency when dealing with complex deformation problems of overburden, or they are unable to take into account both continuous and discontinuous deformation, resulting in deviations between simulation results and actual conditions, making it difficult to predict the deformation and failure process of overburden, which urgently needs to be solved. Summary of the Invention

[0005] This application is based on the inventor's understanding and insights into the following issues:

[0006] For a long time, predecessors have conducted extensive research on the deformation and movement of overlying strata induced by mining, mainly developing theoretical analysis methods, physical model experimental methods, and numerical simulation methods. Among these, numerical simulation methods have been widely adopted due to their economy, convenience, and strong applicability. However, due to severe disturbances, the overlying strata undergo complex deformation, movement, and failure, including deformation, cracking, caving, and compaction, gradually forming four zones: caving zones, fracture zones, bending zones, and surface fracture zones. Specifically, as shown... Figure 1 As shown, therefore, commonly used numerical simulation methods face great difficulties in simulating this type of problem.

[0007] Numerical simulation is an important tool for studying this problem. However, due to the complex deformation, movement and failure of the overlying rock, such as deformation, cracking, collapse and compaction, the process involves both continuous and discontinuous deformation, which makes simulation and prediction very difficult.

[0008] 1) Numerical simulation methods based on continuum mechanics, such as the finite element method and finite difference method, have significant advantages in simulating continuous deformation of overburden induced by mining due to their strong adaptability and high computational efficiency. However, due to mesh dependence, when the disturbed rock mass undergoes large deformations and displacements, some meshes will be distorted, causing simulation results to deviate significantly from reality, or even become uncalculateable. Therefore, there are great difficulties in simulating problems such as cracking, caving, and compaction of overburden.

[0009] 2) Numerical simulation methods based on discontinuous medium mechanics, such as discrete element method and discontinuous deformation analysis, have outstanding advantages in simulating problems such as cracking, collapse and compaction of overburden. However, they require a large number of contact detections and force calculations during the calculation process, which leads to computational efficiency issues. Furthermore, they are not advantageous in simulating continuous deformation problems.

[0010] 3) Compared to methods such as finite element method and finite difference method, meshless methods can completely or partially eliminate the dependence on mesh. They have a significant advantage in simulating discontinuous deformation and cracking problems of overburden, but still face great difficulties in simulating caving and compaction problems, which urgently need to be improved.

[0011] This application provides a smooth point interpolation-discrete element coupled simulation method suitable for coal mining overburden deformation, in order to solve the problems that existing numerical simulation methods are limited by mesh distortion, low computational efficiency, or difficulty in taking into account both continuous and discontinuous deformation when dealing with complex overburden deformation problems, resulting in deviations between simulation results and actual conditions, and inability to accurately predict the deformation and failure process of overburden.

[0012] The first aspect of this application provides a smooth point interpolation-discrete element coupled simulation method suitable for coal mining overburden deformation, comprising the following steps: based on a pre-constructed three-dimensional computational model of a target coal mine, the continuous deformation of the rock strata of the target coal mine is simulated using a meshless smooth point interpolation method, and the deformation parameters corresponding to target units in the rock strata are determined; units in the target units whose deformation parameters are greater than or equal to a preset deformation threshold are marked as units to be converted, and the units to be converted are converted into rigid discrete blocks, and the block discrete element method is used to continue block discrete element simulation of the region corresponding to the rigid discrete block; the meshless smooth point interpolation method is used to perform smooth point interpolation simulation of the region corresponding to the unit whose deformation parameters are less than the preset deformation threshold, and the process of block discrete element simulation and the process of smooth point interpolation simulation are coupled to dynamically simulate the deformation of the rock strata of the target coal mine based on smooth point interpolation-block discrete element coupled simulation.

[0013] Optionally, in one embodiment of this application, before simulating the continuous deformation of the rock strata of the target coal mine using the meshless smooth point interpolation method, the method further includes: establishing a three-dimensional geological model of the target coal mine and subdividing the three-dimensional geological model to obtain an initial three-dimensional calculation model; applying displacement boundary conditions to the initial three-dimensional calculation model and solving the initial stress field and displacement field of the initial three-dimensional calculation model to construct the three-dimensional calculation model that meets the preset conditions.

[0014] Optionally, in one embodiment of this application, marking the units in the target unit whose deformation parameters are greater than or equal to a preset deformation threshold as units to be converted includes: calculating the deformation parameters of at least one unit in the target unit; and marking the at least one unit as a unit to be converted when the deformation parameters of the at least one unit are greater than or equal to the preset deformation threshold.

[0015] Optionally, in one embodiment of this application, the step of converting the unit to be converted into a rigid discrete block includes: obtaining the centroid coordinates of all units to be converted and establishing a minimum bounding box containing the centroid coordinates of all units to be converted; determining a plurality of tetrahedrons corresponding to the centroid coordinates of all units to be converted in the minimum bounding box; identifying the plurality of tetrahedrons as the final units to be converted, and using the final units to be converted to determine the rigid discrete block.

[0016] Optionally, in one embodiment of this application, the dynamic simulation of the deformation of the rock strata of the target coal mine based on the smooth point interpolation-block discrete element coupled simulation method includes: identifying the coupling interface between the smooth point interpolation simulation region and the block discrete element simulation region in the target coal mine; realizing the transmission of coupling information between the smooth point interpolation simulation region and the block discrete element simulation region; and dynamically simulating the deformation of the rock strata of the target coal mine based on the coupling interface and the transmission of coupling information.

[0017] A second aspect of this application provides a smooth point interpolation-discrete element coupled simulation device suitable for coal mining overburden deformation, comprising: a smooth point interpolation analysis module, used to simulate the continuous deformation of the rock strata of the target coal mine using a meshless smooth point interpolation method based on a pre-constructed three-dimensional calculation model of the target coal mine, and determine the deformation parameters corresponding to the target units in the rock strata; a discrete element analysis module, used to mark the units in the target units whose deformation parameters are greater than or equal to a preset deformation threshold as units to be converted, and convert the units to be converted into rigid discrete blocks, and further use the block discrete element method to continue simulating the region corresponding to the rigid discrete blocks; and a coupling module, used to perform smooth point interpolation simulation on the region corresponding to the units whose deformation parameters are less than the preset deformation threshold using the meshless smooth point interpolation method, and couple the process of the block discrete element simulation with the process of the smooth point interpolation simulation, so as to dynamically simulate the deformation of the rock strata of the target coal mine based on smooth point interpolation-block discrete element coupled simulation.

[0018] Optionally, in one embodiment of this application, the apparatus further includes: a model building module, configured to establish a three-dimensional geological model of the target coal mine before simulating the continuous deformation of the rock strata of the target coal mine using a meshless smooth point interpolation method, and to partition the three-dimensional geological model to obtain an initial three-dimensional calculation model; and a calculation initialization module, configured to apply displacement boundary conditions to the initial three-dimensional calculation model before simulating the continuous deformation of the rock strata of the target coal mine using a meshless smooth point interpolation method, and to solve the initial stress field and displacement field of the initial three-dimensional calculation model to construct the three-dimensional calculation model that meets preset conditions.

[0019] Optionally, in one embodiment of this application, the discrete element analysis module includes: a calculation unit for calculating the deformation parameters of at least one of the target units; and a processing unit for marking the at least one unit as a unit to be converted when the deformation parameters of the at least one unit are greater than or equal to the preset deformation threshold.

[0020] Optionally, in one embodiment of this application, the discrete element analysis module includes: an acquisition unit, configured to acquire the centroid coordinates of all units to be transformed and establish a minimum bounding box containing the centroid coordinates of all units to be transformed; a determination unit, configured to determine a plurality of tetrahedrons corresponding to the centroid coordinates of all units to be transformed in the minimum bounding box; and a transformation unit, configured to identify the plurality of tetrahedrons as the final units to be transformed and use the final units to be transformed to determine the rigid discrete block.

[0021] Optionally, in one embodiment of this application, the coupling module includes: an identification unit for identifying the coupling interface between the smooth point interpolation simulation region and the block discrete element simulation region in the target coal mine; an implementation unit for implementing the coupling information transmission between the smooth point interpolation simulation region and the block discrete element simulation region; and a simulation unit for dynamically simulating the deformation of the rock strata in the target coal mine based on the coupling interface and the coupling information transmission.

[0022] A third aspect of this application provides an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the smooth point interpolation-discrete element coupling simulation method suitable for coal mining overburden deformation as described in the above embodiments.

[0023] A fourth aspect of this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the smooth point interpolation-discrete element coupled simulation method suitable for coal mining overburden deformation as described above.

[0024] A fifth aspect of this application provides a computer program product, including a computer program that, when executed, is used to implement the smooth point interpolation-discrete element coupled simulation method suitable for coal mining overburden deformation as described above.

[0025] This application embodiment can be based on a three-dimensional computational model of a coal mine. First, it uses a smooth point interpolation method to simulate the continuous deformation of coal mine strata. Elements in the strata whose deformation parameters exceed a deformation threshold are identified as rigid discrete blocks. The block discrete element method is then used to simulate the corresponding regions of these rigid discrete blocks. Next, the smooth point interpolation method is used to simulate other regions. Finally, the block discrete element simulation process and the smooth point interpolation simulation process are coupled to dynamically simulate the deformation of coal mine strata. This effectively improves computational efficiency and helps analyze the deformation and movement patterns of overburden under mining influence, thereby accurately predicting the deformation and failure process of overburden. Therefore, it solves the problem that existing numerical simulation methods, when dealing with complex overburden deformation problems, are either limited by mesh distortion, have low computational efficiency, or cannot simultaneously consider continuous and discontinuous deformation, leading to deviations between simulation results and actual conditions, and an inability to accurately predict the deformation and failure process of overburden.

[0026] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0027] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0028] Figure 1 This is a schematic diagram of the four zones of overlying strata in the relevant technology;

[0029] Figure 2 This is a flowchart of a smooth point interpolation-discrete element coupled simulation method suitable for coal mining overburden deformation, according to an embodiment of this application;

[0030] Figure 3 This is a schematic diagram of the Z-axis displacement of the rock strata during the first excavation (10m) in a specific embodiment of this application;

[0031] Figure 4 This is a schematic diagram illustrating the calculation principle of a smooth point interpolation method according to a specific embodiment of this application.

[0032] Figure 5 This is a schematic diagram of a three-dimensional calculation model of a goaf area according to a specific embodiment of this application;

[0033] Figure 6 This is a schematic diagram of the equivalent plastic strain of the calculation model when the first excavation is completed, according to a specific embodiment of this application.

[0034] Figure 7 This is a schematic diagram of a smooth point interpolation-discrete element coupling process according to a specific embodiment of this application;

[0035] Figure 8 A flowchart of a smooth point interpolation-discrete element coupled simulation method suitable for coal mining overburden deformation according to a specific embodiment of this application;

[0036] Figure 9 This is a schematic diagram of a smooth point interpolation-discrete element coupling simulation device suitable for coal mining overburden deformation, according to an embodiment of this application.

[0037] Figure 10 This is a schematic diagram of the structure of an electronic device provided according to an embodiment of this application. Detailed Implementation

[0038] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0039] The following describes, with reference to the accompanying drawings, a smooth point interpolation-discrete element coupled simulation method suitable for coal mining overburden deformation according to embodiments of this application. Addressing the problems mentioned in the background section regarding existing numerical simulation methods for handling complex overburden deformation, such as limitations due to mesh distortion, low computational efficiency, or difficulty in balancing continuous and discontinuous deformation, leading to discrepancies between simulation results and actual conditions and an inability to accurately predict overburden deformation and failure processes, this application provides a smooth point interpolation-discrete element coupled simulation method suitable for coal mining overburden deformation. In this method, based on a three-dimensional computational model of a coal mine, the continuous deformation of coal mine strata is simulated using the smooth point interpolation method. Elements in the strata whose deformation parameters exceed a deformation threshold are identified as rigid discrete blocks. The block discrete element method is then used to simulate the corresponding regions of the rigid discrete blocks. Next, the smooth point interpolation method is used to simulate other regions. Finally, the block discrete element simulation process and the smooth point interpolation simulation process are coupled to dynamically simulate the deformation of coal mine strata, effectively improving computational efficiency and aiding in the analysis of the deformation and movement patterns of overburden under mining influence, thereby accurately predicting the deformation and failure processes of overburden. This solves the problem that existing numerical simulation methods, when dealing with complex deformation of overburden, are either limited by mesh distortion, have low computational efficiency, or cannot take into account both continuous and discontinuous deformation, resulting in deviations between simulation results and actual conditions, and failing to accurately predict the deformation and failure process of overburden.

[0040] Specifically, Figure 2 This is a flowchart illustrating a smooth point interpolation-discrete element coupled simulation method suitable for coal mining overburden deformation, provided in an embodiment of this application.

[0041] like Figure 2As shown, the smooth point interpolation-discrete element coupled simulation method suitable for coal overburden deformation includes the following steps:

[0042] In step S201, based on the pre-constructed three-dimensional calculation model of the target coal mine, the continuous deformation of the rock strata of the target coal mine is simulated using the meshless smooth point interpolation method, and the deformation parameters corresponding to the target unit in the rock strata are determined.

[0043] In this embodiment of the application, the target coal mine is a coal mine that requires simulation analysis of overburden deformation; the target unit is a deformation unit in the rock strata.

[0044] It is understood that the embodiments of this application can simulate the continuous deformation of coal mine rock strata based on the three-dimensional calculation model pre-constructed in the following steps. For example, firstly, a linear elastic model and a modified Mohr-Coulomb model are used to simulate the elastoplastic behavior of the rock mass. Then, the mining of coal mines is simulated by omitting the elements in the rock strata. After the first mining step (each mining step excavates 10m), a meshless smooth point interpolation method is first used to simulate the continuous deformation of the rock strata, thereby obtaining the deformation parameters corresponding to each element in the rock strata. For example, Figure 3 As shown, this represents the Z-axis displacement of the rock strata during the first excavation (10m excavation).

[0045] Among them, such as Figure 4 As shown, in order to improve the stability of the meshless smooth point interpolation method, this application proposes an accelerated convergence strategy suitable for global and local iterations. The main strategies are as follows: for global iteration (balance of internal and external forces), a modified Newton-Raphson method is used for solving; for local iteration (stress integration algorithm), the nearest point projection algorithm is used. Based on the modified Newton-Raphson method, a line search method and an adaptive substep method are also used to ensure the stability of the smooth point interpolation program.

[0046] Optionally, in one embodiment of this application, before simulating the continuous deformation of the rock strata of the target coal mine using the meshless smooth point interpolation method, the method further includes: establishing a three-dimensional geological model of the target coal mine and dividing the three-dimensional geological model to obtain an initial three-dimensional calculation model; applying displacement boundary conditions to the initial three-dimensional calculation model and solving the initial stress field and displacement field of the initial three-dimensional calculation model to construct a three-dimensional calculation model that meets preset conditions.

[0047] In practical implementation, this application embodiment can establish a three-dimensional geological model of the study area and perform mesh subdivision on the three-dimensional geological model. Specifically, this application embodiment can establish a three-dimensional geological generalization model of the study area based on exploration data and use tetrahedral meshes to subdivide the model to obtain, for example... Figure 5The initial three-dimensional computational model shown has a length of 1200m, a height of 255m, and a thickness of 10m. After tetrahedral partitioning, it has 6889 nodes and 20771 elements.

[0048] Next, in this embodiment, displacement boundary conditions can be applied to the four sides of the initial three-dimensional calculation model. The main conditions are: the displacement at the bottom of the initial three-dimensional calculation model is fixed, the displacement normal at the four sides is fixed, and the top is free. Then, the mechanical parameters of the rock strata are obtained, and the initial stress field and displacement field of the initial three-dimensional calculation model are solved by elastic constitutive method. The displacement field is then cleared to reduce errors, thereby determining the three-dimensional calculation model and improving calculation efficiency.

[0049] In step S202, the elements in the target element whose deformation parameters are greater than or equal to the preset deformation threshold are marked as elements to be converted, and the elements to be converted are converted into rigid discrete blocks. The block discrete element method is then used to continue to simulate the region corresponding to the rigid discrete block.

[0050] It is understood that, after the first excavation, the embodiments of this application can continuously monitor the deformation degree of each unit in the rock strata, such as strain and stress indices, during subsequent iterative calculations to determine the deformation parameters of each unit. When the deformation parameters exceed a certain deformation threshold, the unit is marked as a unit to be converted. Then, the unit to be converted can be transformed into a rigid discrete block, and the corresponding block discrete element simulation region can be determined based on the rigid discrete block. The block discrete element method can be used to perform deformation simulation on the block discrete element simulation region, effectively improving the simulation accuracy and computational efficiency.

[0051] In the transformed rock mass, under its own weight, the discrete blocks will first crack and collapse. The following criterion can be used for rock mass cracking: when the shear stress between the blocks is greater than the shear strength of the rock mass, the blocks are considered to have cracked. The cracked blocks are then separated from the overlying rock strata and collapse under their own weight.

[0052] Next, the collapsed rock mass may fracture under the pressure of overlying blocks and the squeezing action of adjacent blocks. In fact, the loads exerted on the target block by overlying pressure and adjacent blocks can be simplified into point loads, line loads, and surface loads. Therefore, based on the strength criteria of rock samples under point load experiments, splitting tests (line loads), and uniaxial compression tests (surface loads), fracture models of the block under different load conditions can be established. For example, under point and line loads, if the rock sample experiences tensile failure, and the tensile stress at the contact surface exceeds the tensile strength of the rock mass, the block is considered to have fractured. Under surface loads, the rock sample may experience tensile or shear failure; if the tensile or shear stress at the contact surface exceeds the tensile or shear strength of the rock mass, the block is considered to have fractured, thus achieving multi-stage fracture of the fractured rock mass.

[0053] In one embodiment of this application, marking a unit in the target unit whose deformation parameter is greater than or equal to a preset deformation threshold as a unit to be converted includes: calculating the deformation parameter of at least one unit in the target unit; and marking at least one unit as a unit to be converted when the deformation parameter of at least one unit is greater than or equal to the preset deformation threshold.

[0054] As one possible implementation, this application embodiment can, after the first excavation, continuously monitor the deformation degree of at least one element in the rock stratum, i.e., deformation parameters, such as strain and stress indices, during subsequent iterative calculations. Furthermore, this application can also monitor the deformation degree of multiple elements to improve the accuracy of the simulation, for example, such as... Figure 6 As shown, in this embodiment of the application, equivalent plastic strain can be used as an example. When the equivalent plastic strain of a certain unit exceeds a set threshold (e.g., greater than or equal to 5%), the unit is marked as a unit to be converted, so as to maintain high computational efficiency while ensuring accuracy.

[0055] In one embodiment of this application, converting the unit to be converted into a rigid discrete block includes: obtaining the centroid coordinates of all units to be converted and establishing a minimum bounding box containing the centroid coordinates of all units to be converted; determining multiple tetrahedrons corresponding to the centroid coordinates of all units to be converted in the minimum bounding box; identifying the multiple tetrahedrons as the final units to be converted, and using the final units to be converted to determine the rigid discrete block.

[0056] In some embodiments, after the excavation calculation is completed, it is necessary to determine the area to be transformed, namely the block discrete element simulation area. Specifically, the embodiments of this application can establish a hexahedron that can contain all centroid points and has the smallest volume, namely the minimum bounding box, based on the centroid coordinates of all units to be transformed; then all tetrahedrons whose centroids are inside the bounding box are identified as the final units to be transformed, thereby using the final units to be transformed to determine the area to be transformed.

[0057] It is important to note that the region to be transformed is determined dynamically, rather than in advance. For other regions, i.e., regions not to be transformed, the smooth point interpolation method is still used for simulation.

[0058] In this embodiment, the computational information of discrete blocks can be inherited to initialize the computational information. Specifically, for a created discrete block, the computational information of its interior and boundaries can be inherited from the smooth point interpolation element using direct and interpolation methods. For example, the initial velocity and initial displacement of the block can be obtained through element node interpolation; while the stiffness coefficient of the spring element model between the block boundaries can be obtained based on the contact area of ​​the block and the elastic modulus and shear modulus of the material, effectively improving computational efficiency.

[0059] In step S203, the meshless smooth point interpolation method is used to perform smooth point interpolation simulation on the region corresponding to the element whose deformation parameter is less than the preset deformation threshold. The process of block discrete element simulation and smooth point interpolation simulation are coupled to dynamically simulate the deformation of the rock strata of the target coal mine based on smooth point interpolation-block discrete element coupled simulation.

[0060] It is understood that the embodiments of this application can utilize the meshless smooth point interpolation method to continue smooth point interpolation simulation for the regions corresponding to elements whose deformation parameters are less than a certain deformation threshold (e.g., less than 5%), and couple the smooth point interpolation simulation process with the block discrete element simulation process in the above steps. Thus, the embodiments of this application can simulate the continuous deformation, cracking, caving and compaction process of overburden induced by coal mining based on the smooth point interpolation-block discrete element coupled simulation method, which helps to analyze the deformation and movement law of overburden under the influence of mining and provides technical support for ensuring the engineering construction of the mining area.

[0061] Optionally, in one embodiment of this application, the deformation of the rock strata of the target coal mine is dynamically simulated based on the smooth point interpolation-block discrete element coupled simulation method, including: identifying the coupling interface between the smooth point interpolation simulation region and the block discrete element simulation region in the target coal mine; realizing the coupling information transmission between the smooth point interpolation simulation region and the block discrete element simulation region; and dynamically simulating the deformation of the rock strata of the target coal mine based on the coupling interface and the coupling information transmission.

[0062] In this embodiment, the computational model has two regions: a smooth point interpolation simulation region and a block discrete element simulation region. Therefore, as... Figure 7 As shown, in subsequent simulations, the identification of the coupling interface and the transmission of coupling information need to be considered.

[0063] To avoid complex contact calculations in the discrete element method for block structures, this application proposes the following strategy: A set of spheres solely for contact calculations can be established within the discrete block, transforming complex contact relationships into simple sphere-to-sphere contacts. Taking a tetrahedron as an example, firstly, N1 nodes (excluding vertices) are selected on each edge in a uniform distribution, and N2 nodes (excluding vertices) are selected on each face. Using these nodes and the four vertices of the tetrahedron as centers, spheres with the same radius are constructed, totaling 4 + 6*N1 + 4*N2 spheres. The radius of each sphere can be taken as:

[0064] R = S / N / π 2

[0065] Where S is the surface area of ​​the tetrahedron and N is the number of spheres.

[0066] If the distance between the centers of the spheres inside any two discrete blocks is less than the sum of their radii, then a contact is established, and the contact area is:

[0067] A = π(R1 + R2) 2 / 4

[0068] Where R1 and R2 are the radii of the contacting spheres, respectively. Based on this, a fast method for calculating contact between blocks is established, thereby effectively improving computational efficiency.

[0069] For the identification of coupling interfaces, firstly, based on the subspace method, the search range is narrowed down through the mapping relationship between smooth point interpolation units, discrete blocks, and subspace. Then, contact detection is performed between the spheres inside the block and the boundary surfaces of the smooth point interpolation units, specifically as follows: First, it is determined whether the distance from the sphere to the boundary surface is less than the radius. Then, the center of the sphere is projected onto the boundary surface, and it is determined whether the projection point is located inside a certain boundary surface. If all the above conditions are met, a point-to-surface contact is established, where the contact area is:

[0070] A = πR 2

[0071] Where R is the radius of the sphere.

[0072] For the transmission of coupled information, the coupling variables mainly include velocity and contact force. In this embodiment, the velocity obtained by smooth point interpolation can be transmitted to the discrete element block through the coupling boundary, thereby the discrete element model responds and updates. The contact force generated by the coupling boundary is then returned to the smooth point interpolation model in the form of boundary conditions, thereby the smooth point interpolation model responds and updates until both reach an equilibrium state.

[0073] Therefore, the embodiments of this application can utilize the idea of ​​coupling meshless methods and discrete element methods to simulate the continuous deformation, cracking, caving and compaction process of overburden induced by coal mining. This helps to analyze the deformation and movement law of overburden under the influence of mining and provides technical support for ensuring the engineering construction of mining areas.

[0074] For example, such as Figure 8 As shown, the working principle of the embodiments of this application will be described in detail below with a specific example.

[0075] Step S801: Establish a three-dimensional geological model and perform tetrahedral meshing, that is, establish a three-dimensional geological model of the coal mine study area and perform tetrahedral meshing on the three-dimensional geological model to obtain an initial three-dimensional calculation model.

[0076] Step S802: Apply displacement boundary conditions and perform initial geostress equilibrium, that is, apply displacement boundary conditions to the initial three-dimensional calculation model and perform initial geostress equilibrium to obtain the three-dimensional calculation model.

[0077] Step S803: In the initial stage of mining, a smooth point interpolation method is used for simulation. That is, in the initial stage of coal mining, a meshless smooth point interpolation method is used for excavation simulation.

[0078] Step S804: Establish a smooth point interpolation-discrete element transformation criterion and mark the transformation unit. That is, after the first excavation is completed, pay attention to the degree of deformation of the unit in the rock layer, i.e. the deformation parameter, and mark the unit whose deformation parameter exceeds a certain threshold as the unit that needs to be transformed, i.e. the unit to be transformed.

[0079] Step S805: After the mining step is completed, the bounding box method is used to determine the conversion area.

[0080] Step S806: For the converted discrete block, initialize its computational information, that is, inherit the computational information of the discrete block to realize the initialization of the computational information.

[0081] Step S807: Use the block discrete element method to simulate the cracking, caving and compaction of the overburden, that is, use the block discrete element method to simulate the cracking, caving and compaction of the overburden in the block discrete element simulation area.

[0082] Step S808: Identification of the coupling interface and transmission of coupling information, that is, based on the smooth point interpolation-block discrete element coupling simulation method, the deformation and movement process of coal mine rock strata is simulated, which helps to analyze the deformation and movement law of overburden under the influence of mining and improves the accuracy and computational efficiency of the simulation.

[0083] The smooth point interpolation-discrete element coupled simulation method for coal mining overburden deformation proposed in this application defines rigid discrete blocks as elements in the rock strata whose deformation parameters exceed the deformation threshold. The block discrete element method is then used to simulate the corresponding regions of the rigid discrete blocks. Next, the smooth point interpolation method is used to simulate other regions. Finally, the block discrete element simulation process and the smooth point interpolation simulation process are coupled to dynamically simulate the deformation of coal mine rock strata. This effectively improves computational efficiency and helps analyze the deformation and movement patterns of overburden under mining influence, thereby accurately predicting the deformation and failure process of overburden. This solves the problem that existing numerical simulation methods, when dealing with complex overburden deformation, are either limited by mesh distortion, have low computational efficiency, or cannot simultaneously account for continuous and discontinuous deformation, leading to deviations between simulation results and actual conditions, and failing to accurately predict the deformation and failure process of overburden.

[0084] Next, referring to the accompanying drawings, a smooth point interpolation-discrete element coupled simulation device suitable for coal mining overburden deformation is described according to an embodiment of this application.

[0085] Figure 9 This is a block diagram of a smooth point interpolation-discrete element coupling simulation device suitable for coal mining overburden deformation according to an embodiment of this application.

[0086] like Figure 9 As shown, the smooth point interpolation-discrete element coupled simulation device 10 suitable for coal mining overburden deformation includes: a smooth point interpolation analysis module 100, a discrete element analysis module 200, and a coupling module 300.

[0087] Specifically, the smooth point interpolation analysis module 100 is used to simulate the continuous deformation of the rock strata of the target coal mine based on a pre-constructed three-dimensional calculation model of the target coal mine, using a meshless smooth point interpolation method, and to determine the deformation parameters corresponding to the target unit in the rock strata.

[0088] The discrete element analysis module 200 is used to mark the elements in the target element whose deformation parameters are greater than or equal to the preset deformation threshold as elements to be converted, and to convert the elements to be converted into rigid discrete blocks. The block discrete element method is then used to continue to simulate the region corresponding to the rigid discrete block.

[0089] The coupling module 300 is used to perform smooth point interpolation simulation on the region corresponding to the element whose deformation parameter is less than the preset deformation threshold using the meshless smooth point interpolation method, and to couple the process of block discrete element simulation and smooth point interpolation simulation, so as to dynamically simulate the deformation of the rock strata of the target coal mine based on the smooth point interpolation-block discrete element coupled simulation.

[0090] Optionally, in one embodiment of this application, the apparatus 10 of this application embodiment further includes: a model building module and a calculation initialization module.

[0091] The model building module is used to establish a three-dimensional geological model of the target coal mine before simulating the continuous deformation of the rock strata of the target coal mine using the meshless smooth point interpolation method, and to divide the three-dimensional geological model to obtain an initial three-dimensional calculation model.

[0092] The calculation initialization module is used to apply displacement boundary conditions to the initial three-dimensional calculation model before simulating the continuous deformation of the rock strata of the target coal mine using the meshless smooth point interpolation method, and to solve the initial stress field and displacement field of the initial three-dimensional calculation model in order to construct a three-dimensional calculation model that meets the preset conditions.

[0093] Optionally, in one embodiment of this application, the discrete element analysis module 200 includes a calculation unit and a processing unit.

[0094] The calculation unit is used to calculate the deformation parameters of at least one element in the target element.

[0095] A processing unit is used to mark at least one unit as a unit to be converted when the deformation parameter of at least one unit is greater than or equal to a preset deformation threshold.

[0096] Optionally, in one embodiment of this application, the discrete element analysis module 200 includes: an acquisition unit, a determination unit, and a conversion unit.

[0097] The acquisition unit is used to acquire the centroid coordinates of all units to be transformed and to establish a minimum bounding box containing the centroid coordinates of all units to be transformed.

[0098] The element is determined by identifying multiple tetrahedrons corresponding to the centroid coordinates of all elements to be transformed within the minimum bounding box.

[0099] The transformation unit is used to identify multiple tetrahedrons as the final transformation unit and to determine the rigid discrete block using the final transformation unit.

[0100] Optionally, in one embodiment of this application, the coupling module 300 includes: an identification unit, an implementation unit, and a simulation unit.

[0101] The identification unit is used to identify the coupling interface between the smooth point interpolation simulation region and the block discrete element simulation region in the target coal mine.

[0102] The implementation unit is used to realize the coupling information transmission between the smooth point interpolation simulation region and the block discrete element simulation region.

[0103] The simulation unit is used to dynamically simulate the deformation of rock strata in a target coal mine based on the coupling interface and the transmission of coupling information.

[0104] It should be noted that the foregoing explanation of the smooth point interpolation-discrete element coupling simulation method suitable for coal mining overburden deformation also applies to the smooth point interpolation-discrete element coupling simulation device suitable for coal mining overburden deformation in this embodiment, and will not be repeated here.

[0105] According to the embodiments of this application, a smooth point interpolation-discrete element coupled simulation device suitable for coal mining overburden deformation is proposed. Elements in the rock strata whose deformation parameters exceed the deformation threshold are defined as rigid discrete blocks. The block discrete element method is used to simulate the corresponding regions of the rigid discrete blocks. Then, the smooth point interpolation method is used to simulate other regions. Finally, the block discrete element simulation process and the smooth point interpolation simulation process are coupled to dynamically simulate the deformation of coal mine rock strata. This effectively improves computational efficiency and helps to analyze the deformation and movement patterns of overburden under mining influence, thereby accurately predicting the deformation and failure process of overburden. Therefore, this solves the problem that existing numerical simulation methods, when dealing with complex overburden deformation problems, are either limited by mesh distortion, have low computational efficiency, or cannot simultaneously consider continuous and discontinuous deformation, resulting in deviations between simulation results and actual conditions, and failing to accurately predict the deformation and failure process of overburden.

[0106] Figure 10 A schematic diagram of the structure of an electronic device provided in an embodiment of this application. The electronic device may include:

[0107] The memory 1001, the processor 1002, and the computer program stored on the memory 1001 and capable of running on the processor 1002.

[0108] When the processor 1002 executes the program, it implements the smooth point interpolation-discrete element coupling simulation method suitable for coal mining overburden deformation provided in the above embodiments.

[0109] Furthermore, electronic devices also include:

[0110] Communication interface 1003 is used for communication between memory 1001 and processor 1002.

[0111] The memory 1001 is used to store computer programs that can run on the processor 1002.

[0112] The memory 1001 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.

[0113] If the memory 1001, processor 1002, and communication interface 1003 are implemented independently, then the communication interface 1003, memory 1001, and processor 1002 can be interconnected via a bus to complete communication between them. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be divided into address buses, data buses, control buses, etc. For ease of representation, Figure 10 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0114] Optionally, in a specific implementation, if the memory 1001, processor 1002, and communication interface 1003 are integrated on a single chip, then the memory 1001, processor 1002, and communication interface 1003 can communicate with each other through an internal interface.

[0115] The processor 1002 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of this application.

[0116] This embodiment also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the smooth point interpolation-discrete element coupled simulation method suitable for coal mining overburden deformation as described above.

[0117] This embodiment also provides a computer program product, including a computer program that, when executed, is used to implement the smooth point interpolation-discrete element coupled simulation method suitable for coal mining overburden deformation as described above.

[0118] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0119] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0120] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or N executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0121] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0122] It should be understood that the various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0123] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0124] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0125] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

Claims

1. A smooth point interpolation-discrete element coupled simulation method suitable for coal mining overburden deformation, characterized in that, Includes the following steps: Based on a pre-constructed three-dimensional calculation model of the target coal mine, the continuous deformation of the rock strata of the target coal mine is simulated using a meshless smooth point interpolation method, and the deformation parameters corresponding to the target unit in the rock strata are determined. The units in the target unit whose deformation parameters are greater than or equal to a preset deformation threshold are marked as units to be converted, and the units to be converted are converted into rigid discrete blocks. The block discrete element method is then used to continue to simulate the region corresponding to the rigid discrete block. The meshless smooth point interpolation method is used to perform smooth point interpolation simulation on the region corresponding to the unit whose deformation parameter is less than the preset deformation threshold. The process of block discrete element simulation and the process of smooth point interpolation simulation are coupled to dynamically simulate the deformation of the rock strata of the target coal mine based on smooth point interpolation-block discrete element coupled simulation. The step of converting the unit to be converted into a rigid discrete block includes: obtaining the centroid coordinates of all units to be converted and establishing a minimum bounding box containing the centroid coordinates of all units to be converted; determining multiple tetrahedrons corresponding to the centroid coordinates of all units to be converted in the minimum bounding box; identifying the multiple tetrahedrons as the final units to be converted, and using the final units to be converted to determine the rigid discrete block.

2. The method according to claim 1, characterized in that, Before simulating the continuous deformation of the rock strata in the target coal mine using a meshless smooth point interpolation method, the following steps are also included: A three-dimensional geological model of the target coal mine is established, and the three-dimensional geological model is divided to obtain an initial three-dimensional calculation model; Displacement boundary conditions are applied to the initial three-dimensional calculation model, and the initial stress field and displacement field of the initial three-dimensional calculation model are solved to construct the three-dimensional calculation model that satisfies the preset conditions.

3. The method according to claim 1, characterized in that, The step of marking the units in the target unit whose deformation parameters are greater than or equal to a preset deformation threshold as units to be converted includes: Calculate the deformation parameters of at least one element in the target element; When the deformation parameter of at least one unit is greater than or equal to the preset deformation threshold, the at least one unit is marked as a unit to be converted.

4. The method according to claim 1, characterized in that, The method based on smooth point interpolation-block discrete element coupled simulation is used to dynamically simulate the deformation of the rock strata in the target coal mine, including: Identify the coupling interface between the smooth point interpolation simulation region and the block discrete element simulation region in the target coal mine; To achieve coupling information transfer between the smooth point interpolation simulation region and the block discrete element simulation region; Based on the coupling interface and the coupling information transmission, the deformation of the rock strata in the target coal mine is dynamically simulated.

5. A smooth point interpolation-discrete element coupled simulation device suitable for coal mining overburden deformation, characterized in that, include: The smooth point interpolation analysis module is used to simulate the continuous deformation of the rock strata of the target coal mine based on a pre-constructed three-dimensional calculation model of the target coal mine, using a meshless smooth point interpolation method, and to determine the deformation parameters corresponding to the target unit in the rock strata. The discrete element analysis module is used to mark the units in the target unit whose deformation parameters are greater than or equal to a preset deformation threshold as units to be converted, and to convert the units to be converted into rigid discrete blocks. The block discrete element method is then used to continue simulating the region corresponding to the rigid discrete block. The coupling module is used to perform smooth point interpolation simulation on the region corresponding to the unit whose deformation parameter is less than the preset deformation threshold using the meshless smooth point interpolation method, and to couple the process of block discrete element simulation and the process of smooth point interpolation simulation, so as to dynamically simulate the deformation of the rock strata of the target coal mine based on the smooth point interpolation-block discrete element coupled simulation. The discrete element analysis module includes: an acquisition unit for acquiring the centroid coordinates of all units to be transformed and establishing a minimum bounding box containing the centroid coordinates of all units to be transformed; a determination unit for determining multiple tetrahedrons corresponding to the centroid coordinates of all units to be transformed within the minimum bounding box; and a transformation unit for identifying the multiple tetrahedrons as the final units to be transformed and using the final units to be transformed to determine the rigid discrete block.

6. The apparatus according to claim 5, characterized in that, Also includes: The model building module is used to establish a three-dimensional geological model of the target coal mine before simulating the continuous deformation of the rock strata of the target coal mine using the meshless smooth point interpolation method, and to divide the three-dimensional geological model to obtain an initial three-dimensional calculation model. The calculation initialization module is used to apply displacement boundary conditions to the initial three-dimensional calculation model before simulating the continuous deformation of the rock strata of the target coal mine using the meshless smooth point interpolation method, and to solve the initial stress field and displacement field of the initial three-dimensional calculation model in order to construct the three-dimensional calculation model that meets the preset conditions.

7. The apparatus according to claim 5, characterized in that, The discrete element analysis module includes: A calculation unit is used to calculate the deformation parameters of at least one element in the target element; A processing unit is configured to mark the at least one unit as a unit to be converted when the deformation parameter of the at least one unit is greater than or equal to the preset deformation threshold.

8. The apparatus according to claim 5, characterized in that, The coupling module includes: The identification unit is used to identify the coupling interface between the smooth point interpolation simulation region and the block discrete element simulation region in the target coal mine; The implementation unit is used to realize the coupling information transmission between the smooth point interpolation simulation region and the block discrete element simulation region; The simulation unit is used to dynamically simulate the deformation of the rock strata in the target coal mine based on the coupling interface and the coupling information transmission.

9. An electronic device, characterized in that, include: The memory, the processor, and the computer program stored in the memory and executable on the processor, the processor executing the program to implement the smooth point interpolation-discrete element coupled simulation method for coal mining overburden deformation as described in any one of claims 1-4.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by the processor to implement the smooth point interpolation-discrete element coupled simulation method for coal mining overburden deformation as described in any one of claims 1-4.

11. A computer program product, comprising a computer program, characterized in that, The computer program is executed by a processor to implement the smooth point interpolation-discrete element coupled simulation method for coal mining overburden deformation as described in any one of claims 1-4.

Images