Smooth point interpolation-discrete element coupling simulation method suitable for coal mining overburden deformation

Abstract

The invention 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 deformation, which comprises the following steps: firstly, simulating continuous deformation of a coal mine rock stratum by utilizing a smooth point interpolation method based on a three-dimensional calculation model of a coal mine; the units with the deformation parameters larger than or equal to the deformation threshold value in the rock stratum are marked as to-be-converted units and converted into rigid discrete blocks, and then the areas corresponding to the rigid discrete blocks continue to be simulated through a block discrete element method; and continuously simulating the area corresponding to the unit with the deformation parameter smaller than the deformation threshold value by using a smooth point interpolation method, and coupling the block discrete element simulation process and the smooth point interpolation simulation process so as to dynamically simulate the deformation of the coal mine rock stratum. According to the embodiment of the invention, the deformation movement rule of the overlying strata under the mining influence can be analyzed based on a smooth point interpolation-block discrete element coupling simulation mode, so that the deformation and damage process of the overlying strata can be accurately predicted.

Description

Technical Field

[0001] The present application relates to the technical field of data simulation processing, and in particular to a smooth point interpolation-discrete element coupling simulation method suitable for coal mining overburden deformation. Background Art

[0002] In my country's multi-wheel driven energy system, coal has always been the basic energy source for ensuring energy supply and the main source. In the short term, my country's pattern of using coal resources as the main energy source will not change, and large-scale, high-intensity mining of coal resources will continue for a long time. However, underground coal mining will break the initial stress balance state of the overlying rock strata, causing deformation and movement of the overlying rock, which will in turn cause surface subsidence, posing a huge threat to housing, transportation and pipeline projects in the mining area, and bringing about prominent social, economic and environmental problems. Therefore, it is of great significance to carry out research and prediction on the laws of deformation and movement of overlying rock induced by mining, which will help to formulate scientific and reasonable mining plans, thereby effectively reducing the disasters and losses caused by mining.

[0003] In the related technology, since numerical simulation methods are difficult to simulate mining-induced overburden deformation, cracking, caving and compaction, such problems are studied through coupled simulation methods. For example, the simulation of continuous and discontinuous problems is achieved through the connection and fracture of block boundaries, mainly including CDEM (continuous-discontinuous element method) and FDEM (finite-discrete element method). Continuous problems can also be simulated by using finite element, finite difference and other methods, and discontinuous problems can be simulated by using discrete element and other methods, and data can be exchanged at the coupled boundaries to achieve coupled analysis.

[0004] However, in the related technology, the existing numerical simulation methods are limited by grid distortion, low computational efficiency, or have difficulty in taking into account both continuous and discontinuous deformation when dealing with complex deformation problems of overburden, resulting in deviations between the simulation results and the actual situation. It is difficult to predict the deformation and destruction process of the overburden, which needs to be solved urgently. Summary of the invention

[0005] This application is based on the following problems and understandings made by the inventor:

[0006] For a long time, predecessors have conducted a lot of research on the problem of overburden deformation and movement induced by mining, mainly forming theoretical analysis methods, physical model experimental methods and numerical simulation methods. Among them, the numerical simulation method has been widely used due to its economy, convenience and strong applicability. However, due to severe disturbance, the overburden strata undergo complex deformation, movement and destruction such as deformation, cracking, caving and compaction, and gradually form four zones, namely, collapse zone, fracture zone, bending zone and surface fracture zone. Specifically, Figure 1 As shown, the commonly used numerical simulation methods have great difficulties in simulating this type of problem.

[0007] The numerical simulation method is an important means to study this problem. However, due to the complex deformation, cracking, caving, and compaction of the overlying rock, there are both continuous deformation and discontinuous deformation in this process, resulting in great difficulties in simulation prediction.

[0008] 1) Due to strong adaptability and high computational efficiency, numerical simulation methods based on the theory of continuous medium mechanics, such as finite element method and finite difference method, have outstanding advantages in simulating the continuous deformation problem of overlying rock induced by mining. However, due to grid dependence, when large deformations and displacements occur in the disturbed rock mass, some grids will be distorted, resulting in the simulation results deviating from the actual situation or even being unable to be calculated. Therefore, there are great difficulties in simulating problems such as cracking, caving, and compaction of overlying rock.

[0009] 2) Numerical simulation methods based on the theory of discontinuous medium mechanics, such as discrete element method and discontinuous deformation analysis, have outstanding advantages in simulating problems such as cracking, caving, and compaction of overlying rock. However, a large number of contact detections and force calculations are required during the calculation process, resulting in computational efficiency problems, and they are not dominant in simulating continuous deformation problems.

[0010] 3) Compared with methods such as finite element method and finite difference method, the meshless method can completely or partially eliminate the dependence on grids. It has outstanding advantages in simulating the discontinuous deformation and cracking problems of overlying rock, but there are still great difficulties in simulating caving and compaction problems, which urgently need to be improved.

[0011] This application provides a smooth point interpolation-discrete element coupling simulation method suitable for the deformation of overlying rock in coal mining to solve the problem that existing numerical simulation methods are limited by grid distortion and low computational efficiency, or it is difficult to take into account both continuous and discontinuous deformations when dealing with the complex deformation problem of overlying rock, resulting in a deviation between the simulation results and the actual situation and being unable to accurately predict the deformation and failure process of overlying rock.

[0012] The first aspect of the present application provides a smooth particle interpolation-discrete element coupling simulation method suitable for the deformation of overlying strata in coal mining, including the following steps: Based on a pre-constructed three-dimensional calculation model of the target coal mine, use the meshless smooth particle interpolation method to simulate the continuous deformation of the strata of the target coal mine, and determine the deformation parameters corresponding to the target elements in the strata; Mark the elements in the target elements whose deformation parameters are greater than or equal to a preset deformation threshold as elements to be converted, and convert the elements to be converted into rigid discrete blocks, and use the block discrete element method to continue the block discrete element simulation for the area corresponding to the rigid discrete blocks; Use the meshless smooth particle interpolation method to perform smooth particle interpolation simulation on the area corresponding to the elements whose deformation parameters are less than the preset deformation threshold, and couple the process of the block discrete element simulation and the process of the smooth particle interpolation simulation, so as to dynamically simulate the deformation of the strata of the target coal mine based on the smooth particle interpolation-block discrete element coupling simulation method.

[0013] Optionally, in an embodiment of the present application, before using the meshless smooth particle interpolation method to simulate the continuous deformation of the strata of the target coal mine, it further includes: Establish a three-dimensional geological model of the target coal mine, and divide the three-dimensional geological model to obtain an initial three-dimensional calculation model; Apply displacement boundary conditions to the initial three-dimensional calculation model, and solve 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 an embodiment of the present application, the step of marking the elements in the target elements whose deformation parameters are greater than or equal to a preset deformation threshold as elements to be converted includes: Calculate the deformation parameters of at least one element in the target element; When the deformation parameters of the at least one element are greater than or equal to the preset deformation threshold, mark the at least one element as an element to be converted.

[0015] Optionally, in an embodiment of the present application, the step of converting the elements to be converted into rigid discrete blocks includes: Obtain the centroid coordinates of all elements to be converted, and establish a minimum bounding box including the centroid coordinates of all elements to be converted; Determine a plurality of tetrahedrons corresponding to the centroid coordinates of all elements to be converted in the minimum bounding box; Identify the plurality of tetrahedrons as the final elements to be converted, and use the final elements to be converted to determine the rigid discrete blocks.

[0016] Optionally, in an embodiment of the present application, the method for dynamically simulating the deformation of the rock strata of the target coal mine based on the smooth point interpolation-block discrete element coupling simulation includes: identifying the coupling interface between the smooth point interpolation simulation area and the block discrete element simulation area in the target coal mine; realizing the coupling information transfer between the smooth point interpolation simulation area and the block discrete element simulation area; and dynamically simulating the deformation of the rock strata of the target coal mine based on the coupling interface and the coupling information transfer.

[0017] An embodiment of the second aspect of the present application provides a smooth point interpolation-discrete element coupling simulation device suitable for the deformation of overlying strata in coal mining, including: a smooth point interpolation analysis module, configured to simulate the continuous deformation of the rock strata of the target coal mine by using the 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 unit in the rock strata; a discrete element analysis module, configured to mark the unit whose deformation parameter in the target unit is greater than or equal to a preset deformation threshold as a unit to be converted, convert the unit to be converted into a rigid discrete block, and further use the block discrete element method to continue simulating the area corresponding to the rigid discrete block; and a coupling module, configured to perform smooth point interpolation simulation on the area corresponding to the unit whose deformation parameter is less than the preset deformation threshold by using the meshless smooth point interpolation method, and couple the process of the block discrete element simulation and 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 the smooth point interpolation-block discrete element coupling simulation method.

[0018] Optionally, in an embodiment of the present application, the device of the embodiment of the present application further includes: a model construction module, configured to establish a three-dimensional geological model of the target coal mine and perform meshing on the three-dimensional geological model to obtain an initial three-dimensional calculation model before simulating the continuous deformation of the rock strata of the target coal mine by using the meshless smooth point interpolation method; and a calculation initialization module, configured to apply displacement boundary conditions to the initial three-dimensional calculation model and solve 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 before simulating the continuous deformation of the rock strata of the target coal mine by using the meshless smooth point interpolation method.

[0019] Optionally, in an embodiment of the present application, the discrete element analysis module includes: a calculation unit, configured to calculate the deformation parameters of at least one unit in the target unit; and a processing unit, 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.

[0020] Optionally, in an embodiment of the present application, the discrete element analysis module includes: an acquisition unit configured to acquire the centroid coordinates of all units to be converted and establish a minimum bounding box including the centroid coordinates of all the units to be converted; a determination unit configured to determine a plurality of tetrahedrons corresponding to the centroid coordinates of all the units to be converted in the minimum bounding box; and a conversion unit configured to identify the plurality of tetrahedrons as the final units to be converted and determine the rigid discrete blocks by using the final units to be converted.

[0021] Optionally, in an embodiment of the present application, the coupling module includes: an identification unit configured to identify a coupling interface between a smooth point interpolation simulation area and a block discrete element simulation area in the target coal mine; an implementation unit configured to implement coupling information transfer between the smooth point interpolation simulation area and the block discrete element simulation area; and a simulation unit configured to dynamically simulate the deformation of the rock formation of the target coal mine based on the coupling interface and the coupling information transfer.

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

[0023] An embodiment of the fourth aspect of the present application provides a computer-readable storage medium storing a computer program, and when the program is executed by a processor, it implements the smooth point interpolation-discrete element coupling simulation method suitable for overburden deformation in coal mining as described above.

[0024] An embodiment of the fifth aspect of the present application provides a computer program product including a computer program, and when the computer program is executed, it is used to implement the smooth point interpolation-discrete element coupling simulation method suitable for overburden deformation in coal mining as described above.

[0025] Embodiments of the present application can be based on a three-dimensional calculation model of a coal mine. First, the smooth point interpolation method is used to simulate the continuous deformation of the coal mine rock strata, and the units in the rock strata whose deformation parameters exceed the deformation threshold are determined as rigid discrete blocks. Then, the block discrete element method is used to continue the simulation of the area corresponding to the rigid discrete blocks. Next, the smooth point interpolation method is used to continue the simulation of other areas. Finally, the process of block discrete element simulation and the process of smooth point interpolation simulation are coupled to dynamically simulate the deformation of the coal mine rock strata, effectively improving the calculation efficiency, helping to analyze the deformation and movement law of overlying strata under mining influence, and thus accurately predicting the deformation and failure process of overlying strata. Thereby, it solves the problem that existing numerical simulation methods, when dealing with the complex deformation problem of overlying strata, are either limited by mesh distortion and low calculation efficiency, or difficult to take into account both continuous and discontinuous deformations, resulting in a deviation between the simulation results and the actual situation and being unable to accurately predict the deformation and failure process of overlying strata.

[0026] Additional aspects and advantages of the present application will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and / or additional aspects and advantages of the present application will become apparent and easy to understand from the following description of the embodiments in conjunction with the drawings, where:

[0028] Figure 1 is a schematic diagram of the four zones of the overlying strata in the related art;

[0029] Figure 2 is a flowchart of a smooth point interpolation-discrete element coupling simulation method suitable for the deformation of overlying strata in coal mining according to an embodiment of the present application;

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

[0031] Figure 4 is a schematic diagram of the calculation principle of the smooth point interpolation method in a specific embodiment of the present application;

[0032] Figure 5 is a schematic diagram of the three-dimensional calculation model of the goaf in a specific embodiment of the present application;

[0033] Figure 6 is a schematic diagram of the equivalent plastic strain of the calculation model when the first excavation is completed in a specific embodiment of the present application;

[0034] Figure 7 is a schematic diagram of the smooth point interpolation-discrete element coupling process in a specific embodiment of the present application;

[0035] Figure 8 The flowchart of the smoothed particle hydrodynamics-discrete element coupling simulation method suitable for the deformation of overlying strata in coal mining according to a specific embodiment of the present application;

[0036] Figure 9 The structural schematic diagram of a smoothed particle hydrodynamics-discrete element coupling simulation device suitable for the deformation of overlying strata in coal mining provided according to an embodiment of the present application;

[0037] Figure 10 The structural schematic diagram of an electronic device provided according to an embodiment of the present application. Specific embodiments

[0038] The embodiments of the present application will be described in detail below. The examples of the embodiments are shown in the accompanying drawings, where 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 are intended to explain the present application and should not be construed as limiting the present application.

[0039] The smoothed particle hydrodynamics-discrete element coupling simulation method suitable for the deformation of overlying strata in coal mining according to an embodiment of the present application will be described below with reference to the accompanying drawings. In view of the problems in the existing numerical simulation methods mentioned in the above background technology, when dealing with the complex deformation problems of overlying strata, they are either limited by mesh distortion and low computational efficiency, or it is difficult to take into account both continuous and discontinuous deformations, resulting in deviations between the simulation results and the actual situation, and it is impossible to accurately predict the deformation and failure process of overlying strata. The present application provides a smoothed particle hydrodynamics-discrete element coupling simulation method suitable for the deformation of overlying strata in coal mining. In this method, based on the three-dimensional calculation model of the coal mine, the smoothed particle hydrodynamics method can be used to simulate the continuous deformation of coal mine rock strata, and the units in the rock strata whose deformation parameters exceed the deformation threshold are determined as rigid discrete blocks, and the block discrete element method is used to continue the simulation of the area corresponding to the rigid discrete blocks. Then, the smoothed particle hydrodynamics method is used to simulate other areas, and finally, the process of block discrete element simulation and the process of smoothed particle hydrodynamics simulation are coupled to dynamically simulate the deformation of coal mine rock strata, effectively improving the computational efficiency, helping to analyze the deformation and movement laws of overlying strata under mining influence, and thus accurately predicting the deformation and failure process of overlying strata. Thus, the problems in the existing numerical simulation methods when dealing with the complex deformation problems of overlying strata, such as being limited by mesh distortion and low computational efficiency, or being difficult to take into account both continuous and discontinuous deformations, resulting in deviations between the simulation results and the actual situation, and it is impossible to accurately predict the deformation and failure process of overlying strata, are solved.

[0040] Specifically, Figure 2 The flow schematic diagram of a smoothed particle hydrodynamics-discrete element coupling simulation method suitable for the deformation of overlying strata in coal mining provided according to an embodiment of the present application.

[0041] As Figure 2As shown in the figure, the smooth particle hydrodynamics-discrete element coupling simulation method suitable for overlying strata deformation in coal mining includes the following steps:

[0042] In step S201, based on the pre-constructed three-dimensional calculation model of the target coal mine, the meshless smooth particle hydrodynamics method is used to simulate the continuous deformation of the rock strata of the target coal mine, and the deformation parameters corresponding to the target elements in the rock strata are determined.

[0043] In the embodiment of the present application, the target coal mine is the coal mine that needs to conduct overlying strata deformation simulation analysis; the target element is the deformation unit in the rock strata.

[0044] It can be understood that the embodiment of the present application can simulate the continuous deformation of the coal mine rock strata based on the pre-constructed three-dimensional calculation model in the following steps. For example, first, the elastic-plastic behavior of the rock mass is simulated using the linear elastic model and the modified Mohr-Coulomb model. Then, the coal mine mining is simulated by emptying the elements in the rock strata. After the first mining step (each mining step excavates 10 m) is completed, the meshless smooth particle hydrodynamics method is first used to simulate the continuous deformation of the rock strata, so that the deformation parameters corresponding to each element in the rock strata can be obtained. Among them, as Figure 3 shown, it is the Z-direction displacement of the rock strata during the first excavation (excavating 10 m).

[0045] Among them, as Figure 4 shown, in order to improve the stability of the meshless smooth particle hydrodynamics method program, the embodiment of the present application proposes an accelerated convergence strategy suitable for global iteration and local iteration, mainly: for global iteration (the balance of internal and external forces), the modified Newton-Raphson method is used to solve; for local iteration (stress integration algorithm), the nearest point projection algorithm is used, and on the basis of the modified Newton-Raphson method, the line search method and the adaptive sub-step method are used to ensure the stability of the smooth particle hydrodynamics program.

[0046] Optionally, in an embodiment of the present application, before using the meshless smooth particle hydrodynamics method to simulate the continuous deformation of the rock strata of the target coal mine, it 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 the preset conditions.

[0047] In the actual execution process, the embodiment of the present application can establish a three-dimensional geological model of the study area and perform grid division on the three-dimensional geological model. Specifically, the embodiment of the present application can establish a three-dimensional geological generalization model of the study area based on the exploration data, and use tetrahedral grids for model division to obtain as Figure 5The initial three-dimensional calculation model shown, where the length of the initial three-dimensional calculation model is 1200m, the height is 255m, and the thickness is 10m; after tetrahedral meshing, the number of nodes is 6889 and the number of elements is 20771.

[0048] Next, the embodiments of the present application can apply displacement boundary conditions to the four sides of the initial three-dimensional calculation model, mainly: the displacement at the bottom of the initial three-dimensional calculation model is fixed, the displacement in the normal direction around is fixed, and the top is free; then, obtain the mechanical parameters of the rock formation, and adopt the elastic constitutive method to solve the initial stress field and displacement field of the initial three-dimensional calculation model, and clear the displacement field to reduce errors, so as to determine the three-dimensional calculation model and improve the 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, and the block discrete element method is used to continue the block discrete element simulation for the area corresponding to the rigid discrete blocks.

[0050] It can be understood that the embodiments of the present application can, after the first excavation is completed, during the subsequent iterative calculation process, always pay attention to the deformation degree of each element in the rock formation, such as strain and stress indicators, to determine the deformation parameters of each element. When the deformation parameters of an element exceed a certain deformation threshold, it is marked as an element to be converted. Then, the element to be converted can be converted into a rigid discrete block, and the corresponding block discrete element simulation area can be determined according to the rigid discrete block, so as to use the block discrete element method to perform deformation simulation on the block discrete element simulation area, effectively improving the accuracy and calculation efficiency of the simulation.

[0051] Among them, for the transformed rock mass, under the action of self-weight, the blocks in the discrete area will first crack and fall. For rock mass cracking, the following criterion can be used: when the shear stress between blocks is greater than the shear strength of the rock mass, it is determined that the block cracks, and the cracked block is peeled off from the overlying rock formation and falls under the action of self-weight.

[0052] Next, for the rock mass after caving, under the action of overlying pressure and extrusion from adjacent blocks, the blocks may break. In fact, the load forms of the overlying pressure and adjacent blocks on the target block can be simplified into point load, line load, and surface load. Therefore, based on the strength criteria of rock block specimens under point load test, splitting test (line load), and uniaxial compression test (surface load), fracture models of blocks under different load forms can be established. For example, for point load and line load, tensile failure occurs in the rock sample. When the tensile stress on the contact surface is greater than the tensile strength of the rock mass, it is determined that the block has fractured; for surface load, tensile failure or shear failure may occur in the rock sample. As long as the tensile stress or shear stress on the contact surface is greater than the tensile strength or shear strength of the rock mass, it is determined that the block has fractured, thus realizing multi-stage fragmentation of the broken rock mass.

[0053] Among them, in one embodiment of the present application, the units in the target unit with deformation parameters greater than or equal to the preset deformation threshold are marked as units to be converted, including: calculating the deformation parameters of at least one unit in the target unit; when the deformation parameters of at least one unit are greater than or equal to the preset deformation threshold, marking at least one unit as a unit to be converted.

[0054] As a possible implementation method, in the embodiment of the present application, after the first excavation is completed, during the subsequent iterative calculation process, the deformation degree of at least one unit in the rock formation, that is, the deformation parameter, such as strain and stress indicators, can be continuously monitored. In addition, the present application can also pay attention to the deformation degree of multiple units to improve the accuracy of simulation. For example, as Figure 6 shown, in the embodiment of the present application, taking the equivalent plastic strain as an example, when the equivalent plastic strain of a certain unit exceeds the set threshold (for example, when it is greater than or equal to 5%), that unit is marked as a unit to be converted, so as to maintain a high calculation efficiency while ensuring accuracy.

[0055] Among them, in one embodiment of the present application, converting the units to be converted into rigid discrete blocks 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 blocks.

[0056] In some embodiments, after the calculation of the current excavation is completed, the area to be converted, that is, the block discrete element simulation area, needs to be determined. Specifically, in the embodiment of the present application, based on the centroid coordinates of all units to be converted, a hexahedron that can contain all centroid points and has the smallest volume, that is, the minimum bounding box, can be established; then all tetrahedrons with centroids inside the bounding box are identified as the final units to be converted, so as to determine the area to be converted by using the final units to be converted.

[0057] It should be noted that the determination of the area to be transformed is carried out dynamically rather than determined in advance. For other areas, that is, the areas not to be transformed, the smooth point interpolation method is still used for simulation.

[0058] Among them, the embodiments of the present application can perform discrete block calculation information inheritance to realize the initialization of calculation information. Specifically, for the created discrete blocks, the calculation information inside and on the boundary of the blocks can be inherited from the smooth point interpolation elements by the direct method and the interpolation method. For example, the initial velocity and initial displacement of the blocks can be obtained by interpolating the unit nodes; and the stiffness coefficient of the spring element model between the block boundaries can be obtained according to the contact area of the blocks and the elastic modulus and shear modulus of the material, effectively improving the calculation efficiency.

[0059] In step S203, the smooth point interpolation simulation is performed on the area corresponding to the elements with deformation parameters less than the preset deformation threshold by using the meshless smooth point interpolation method, and the process of the block discrete element simulation and the process of the smooth point interpolation simulation are coupled, so as to dynamically simulate the deformation of the rock stratum of the target coal mine in the manner of smooth point interpolation-block discrete element coupled simulation.

[0060] It can be understood that the embodiments of the present application can use the meshless smooth point interpolation method to continue the smooth point interpolation simulation on the area corresponding to the elements with deformation parameters less than a certain deformation threshold (such as less than 5%), and couple the process of this smooth point interpolation simulation with the process of the block discrete element simulation in the above steps. Therefore, the embodiments of the present application can simulate the process of continuous deformation, cracking, caving and compaction of the overlying rock 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 the overlying rock under mining influence and provides technical support for ensuring the engineering construction in the mining area.

[0061] Optionally, in an embodiment of the present application, based on the smooth point interpolation-block discrete element coupled simulation method, dynamically simulating the deformation of the rock stratum of the target coal mine includes: identifying the coupling interface between the smooth point interpolation simulation area and the block discrete element simulation area in the target coal mine; realizing the coupling information transfer between the smooth point interpolation simulation area and the block discrete element simulation area; and dynamically simulating the deformation of the rock stratum of the target coal mine based on the coupling interface and the coupling information transfer.

[0062] In the embodiments of the present application, there are two areas in the calculation model, namely the smooth point interpolation simulation area and the block discrete element simulation area. Therefore, as Figure 7 shown, in the subsequent simulation, it is necessary to consider the identification of the coupling interface and the transfer of the coupling information.

[0063] Among them, in order to avoid complex contact calculations in the block discrete element method, the embodiments of the present application can propose the following strategy: a set of spheres only used for contact calculations can be established inside the discrete blocks, and then the complex contact calculation relationship can be transformed into simple sphere-sphere contact. Taking a tetrahedron as an example, first, N1 nodes (excluding vertices) are selected on each edge and N2 nodes (excluding vertices) are selected on each face in a uniformly distributed manner. Spheres with the same radius are established with the above nodes and the 4 vertices of the tetrahedron as the centers of the spheres, totaling 4 + 6 * N1 + 4 * N2. Among them, the radius of each sphere can be taken as:

[0064] R = S / N / π 2

[0065] Among them, 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, contact is established, and the contact area:

[0067] A = π(R1 + R2) 2 / 4

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

[0069] For the identification of the coupling interface, first, based on the subspace method, the search range is reduced through the mapping relationship between the smoothed point interpolation element, the discrete block and the subspace. Then, contact detection is performed between the spheres inside the block and the boundary surface of the smoothed point interpolation element. Specifically, first, it is judged whether the distance from the sphere to the boundary surface is less than the radius, and then the center of the sphere is projected onto the boundary surface to judge whether the projection point is inside a certain boundary surface. If the above conditions are all met, point-surface contact is established, and the contact area:

[0070] A = πR 2

[0071] Among them, R is the radius of the sphere.

[0072] For the transfer of coupling information, the coupling variables mainly include velocity and contact force. The embodiments of the present application can transfer the velocity obtained by the smoothed point interpolation solution to the discrete element block through the coupling boundary, and the discrete element model responds and updates accordingly. The contact force generated on the coupling boundary is then returned to the smoothed point interpolation model in the form of boundary conditions, and the smoothed point interpolation model responds and updates accordingly until both reach an equilibrium state.

[0073] Therefore, the embodiments of the present application can utilize the idea of coupling the meshless method and the discrete element method to simulate the continuous deformation, cracking, caving, and compaction processes of overlying strata induced by coal mining, which helps to analyze the deformation and movement laws of overlying strata under mining influence and provides technical support for ensuring engineering construction in mining areas.

[0074] For example, as Figure 8 shown, the working principle of the embodiments of the present application will be elaborated in detail with a specific embodiment below.

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

[0076] Step S802: Apply displacement boundary conditions and perform initial in-situ stress balancing, that is, apply displacement boundary conditions to the initial three-dimensional calculation model and perform initial in-situ stress balancing to obtain a three-dimensional calculation model.

[0077] Step S803: In the initial stage of mining, use the smoothed point interpolation method for simulation, that is, in the initial stage of coal mine mining, use the meshless smoothed point interpolation method for excavation simulation.

[0078] Step S804: Establish a smoothed point interpolation-discrete element conversion criterion and mark the conversion units, that is, after the first excavation is completed, pay attention to the deformation degree of the units in the rock stratum at all times, that is, the deformation parameters, and the units with deformation parameters exceeding a certain threshold can be marked as the units to be converted, that is, the units to be converted.

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

[0080] Step S806: For the converted discrete blocks, initialize their calculation information, that is, inherit the discrete block calculation information to achieve the initialization of the calculation information.

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

[0082] Step S808: Identification of the coupling interface and transfer of coupling information, that is, based on the smoothed point interpolation-block discrete element coupling simulation method, simulate the deformation and movement process of coal mine rock strata, which helps to analyze the deformation and movement laws of overlying strata under mining influence and improve the accuracy and calculation efficiency of the simulation.

[0083] According to the smooth particle hydrodynamics-discrete element coupling simulation method for overlying strata deformation suitable for coal mining proposed in the embodiments of the present application, the units in the strata with deformation parameters exceeding the deformation threshold are determined as rigid discrete blocks, and the block discrete element method is used to continue the simulation of the area corresponding to the rigid discrete blocks. Then, the smooth particle hydrodynamics method is used to simulate other areas. Finally, the processes of block discrete element simulation and smooth particle hydrodynamics simulation are coupled to dynamically simulate the deformation of coal mine strata, effectively improving the calculation efficiency, helping to analyze the deformation and movement laws of overlying strata under mining influence, and thus accurately predicting the deformation and failure processes of overlying strata. Thereby, it solves the problem that the existing numerical simulation methods, when dealing with the complex deformation problems of overlying strata, are either limited by mesh distortion and low calculation efficiency, or difficult to take into account both continuous and discontinuous deformations, resulting in deviations between the simulation results and the actual situation and being unable to accurately predict the deformation and failure processes of overlying strata.

[0084] Next, refer to the drawings to describe the smooth particle hydrodynamics-discrete element coupling simulation device for overlying strata deformation suitable for coal mining proposed in the embodiments of the present application.

[0085] Figure 9 It is a block diagram of the smooth particle hydrodynamics-discrete element coupling simulation device for overlying strata deformation suitable for coal mining in the embodiments of the present application.

[0086] As Figure 9 shown, the smooth particle hydrodynamics-discrete element coupling simulation device 10 for overlying strata deformation suitable for coal mining includes: a smooth particle hydrodynamics analysis module 100, a discrete element analysis module 200, and a coupling module 300.

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

[0088] The discrete element analysis module 200 is used to mark the units in the target units with deformation parameters greater than or equal to the preset deformation threshold as units to be converted, convert the units to be converted into rigid discrete blocks, and further use the block discrete element method to continue the simulation of the area corresponding to the rigid discrete blocks.

[0089] The coupling module 300 is used to perform smooth particle hydrodynamics simulation on the area corresponding to the units with deformation parameters less than the preset deformation threshold by using the meshless smooth particle hydrodynamics method, and couple the processes of block discrete element simulation and smooth particle hydrodynamics simulation to dynamically simulate the deformation of the strata of the target coal mine based on the smooth particle hydrodynamics-block discrete element coupling simulation method.

[0090] Optionally, in an embodiment of the present application, the device 10 of the embodiment of the present application further includes: a model construction module and a calculation initialization module.

[0091] The model construction module is used to establish a three-dimensional geological model of the target coal mine and perform meshing on the three-dimensional geological model to obtain an initial three-dimensional calculation model before simulating the continuous deformation of the rock stratum of the target coal mine by using the meshless smooth point interpolation method.

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

[0093] Optionally, in an embodiment of the present 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 unit in the target unit.

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

[0096] Optionally, in an embodiment of the present 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 converted and establish a minimum bounding box containing the centroid coordinates of all units to be converted.

[0098] The determination unit is used to determine a plurality of tetrahedrons corresponding to the centroid coordinates of all units to be converted in the minimum bounding box.

[0099] The conversion unit is used to identify the plurality of tetrahedrons as the final units to be converted and determine rigid discrete blocks by using the final units to be converted.

[0100] Optionally, in an embodiment of the present 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 area and the block discrete element simulation area in the target coal mine.

[0102] The implementation unit is used to implement the coupling information transfer between the smooth point interpolation simulation area and the block discrete element simulation area.

[0103] A simulation unit for dynamically simulating the deformation of the strata in a target coal mine based on a coupling interface and coupling information transfer.

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

[0105] According to the smooth point interpolation-discrete element coupling simulation device suitable for the deformation of overlying strata in coal mining proposed in the embodiments of the present application, the units in the strata with deformation parameters exceeding the deformation threshold are determined as rigid discrete blocks, and the block discrete element method is used to continue the simulation of the area corresponding to the rigid discrete blocks. Then, the smooth point interpolation method is used to simulate other areas. Finally, the processes of block discrete element simulation and smooth point interpolation simulation are coupled to dynamically simulate the deformation of the coal mine strata, effectively improving the calculation efficiency, helping to analyze the deformation and movement laws of the overlying strata under mining influence, and thus accurately predicting the deformation and failure process of the overlying strata. Thereby, the problem that the existing numerical simulation methods are limited by grid distortion, low calculation efficiency, or difficult to balance continuous and discontinuous deformations when dealing with complex deformation problems of overlying strata, resulting in deviations between the simulation results and the actual situation and being unable to accurately predict the deformation and failure process of the overlying strata is solved.

[0106] Figure 10 The structural schematic diagram of the electronic device provided by the embodiments of the present application. The electronic device may include:

[0107] A memory 1001, a processor 1002, and a computer program stored on the memory 1001 and executable on the processor 1002.

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

[0109] Further, the electronic device further includes:

[0110] A communication interface 1003 for communication between the memory 1001 and the processor 1002.

[0111] The memory 1001 is used to store a computer program executable on the processor 1002.

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

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

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

[0115] The processor 1002 may be a Central Processing Unit (CPU), or an Application Specific Integrated Circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application.

[0116] This embodiment also provides a computer-readable storage medium, on which a computer program is stored. When the program is executed by a processor, it implements the smooth point interpolation-discrete element coupling simulation method suitable for coal mining overlying strata deformation as described above.

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

[0118] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples", etc., mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of this application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or N embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0119] In addition, the terms "first" and "second" are used only for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of this application, the meaning of "N" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0120] Any process or method description in a flowchart or described in other ways herein can be understood to represent a module, segment, or portion of code including one or N executable instructions for implementing a customized logical function or process, and the scope of the preferred embodiments of this application includes additional implementations, where the functions can be executed in a manner that is not in the order shown or discussed, including in a substantially simultaneous manner according to the functions involved or in a reverse order, which should be understood by those skilled in the art to which the 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 definitional sequence list of executable instructions for implementing logical functions, which can be specifically implemented in any computer-readable medium for use by an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other systems that can fetch and execute instructions from the instruction execution system, apparatus, or device), or used in conjunction with these instruction execution systems, apparatus, or devices. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program 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 the following: an electrical connection portion (electronic device) having one or N wirings, a portable computer diskette (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically by optically scanning the paper or other media, followed by editing, interpretation, or otherwise processing as appropriate, and then stored in a computer memory.

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

[0123] Those of ordinary skill in the art of this technology can understand that all or part of the steps carried by the methods of the above-described embodiments can be completed by instructing relevant hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiments.

[0124] In addition, each functional unit in various embodiments of the present application may be integrated into one processing module, or each unit may exist physically alone, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. When the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

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

Claims

1. A smooth particle interpolation-discrete element coupling simulation method suitable for the deformation of overlying strata in coal mining, characterized in that Including the following steps: Based on a pre - constructed three - dimensional calculation model of the target coal mine, using the meshless smoothed particle hydrodynamics method to simulate the continuous deformation of the rock strata of the target coal mine, and determining the deformation parameters corresponding to the target elements in the rock strata; Marking the elements in the target elements whose deformation parameters are greater than or equal to a preset deformation threshold as elements to be converted, and converting the elements to be converted into rigid discrete blocks, and using the block - based discrete element method to continue the block - based discrete element simulation for the area corresponding to the rigid discrete blocks; Using the meshless smoothed particle hydrodynamics method to perform smoothed particle interpolation simulation on the area corresponding to the elements whose deformation parameters are less than the preset deformation threshold, and coupling the process of the block - based discrete element simulation and the process of the smoothed particle interpolation simulation, so as to dynamically simulate the deformation of the rock strata of the target coal mine in the way of smoothed particle interpolation - block - based discrete element coupling simulation.

2. The method according to claim 1, characterized in that Before using the meshless smoothed particle hydrodynamics method to simulate the continuous deformation of the rock strata of the target coal mine, it 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 the three - dimensional calculation model that meets the preset conditions.

3. The method according to claim 1, wherein The marking the elements in the target elements whose deformation parameters are greater than or equal to a preset deformation threshold as elements to be converted includes: Calculating the deformation parameters of at least one element in the target element; When the deformation parameters of the at least one element are greater than or equal to the preset deformation threshold, marking the at least one element as an element to be converted.

4. The method according to claim 1, characterized in that, The converting the elements to be converted into rigid discrete blocks includes: Obtaining the centroid coordinates of all elements to be converted, and establishing a minimum bounding box containing the centroid coordinates of all elements to be converted; Determining a plurality of tetrahedrons corresponding to the centroid coordinates of all elements to be converted in the minimum bounding box; Identifying the plurality of tetrahedrons as the final elements to be converted, and using the final elements to be converted to determine the rigid discrete blocks.

5. The method according to claim 1, wherein The dynamically simulating the deformation of the rock strata of the target coal mine in the way of smoothed particle interpolation - block - based discrete element coupling simulation includes: Identifying the coupling interface between the smoothed particle interpolation simulation area and the block - based discrete element simulation area in the target coal mine; Implementing the coupling information transfer between the smoothed particle interpolation simulation area and the block - based discrete element simulation area; Based on the coupling interface and the coupling information transfer, dynamically simulating the deformation of the rock strata of the target coal mine.

6. A smooth particle interpolation-discrete element coupling simulation device suitable for overlying strata deformation in coal mining, characterized in that, Including: A smoothed particle interpolation analysis module, which 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 the meshless smoothed particle hydrodynamics method, and determining the deformation parameters corresponding to the target elements in the rock strata; A discrete element analysis module is used to mark the unit whose deformation parameter in the target unit is greater than or equal to a preset deformation threshold as a unit to be converted, and convert the unit to be converted into a rigid discrete block, and further use a block discrete element method to continue simulating the area corresponding to the rigid discrete block; A coupling module is used to use the gridless smooth point interpolation method to perform smooth point interpolation simulation on the area corresponding to the unit whose deformation parameter is less than the preset deformation threshold, and to couple the block discrete element simulation process with the smooth point interpolation simulation process, so as to dynamically simulate the deformation of the rock formation of the target coal mine based on the smooth point interpolation-block discrete element coupling simulation.

7. The device according to claim 6, characterized in that, Also includes: A model building module, used for building 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 before simulating the continuous deformation of the rock layer of the target coal mine by using a gridless smooth point interpolation method; The calculation initialization module is used to apply displacement boundary conditions to the initial three-dimensional calculation model and solve the initial stress field and displacement field of the initial three-dimensional calculation model before simulating the continuous deformation of the rock layer of the target coal mine using the gridless smooth point interpolation method, so as to construct the three-dimensional calculation model that meets the preset conditions.

8. The device according to claim 6, characterized in that The discrete element analysis module includes: A calculation unit, used for calculating a deformation parameter of at least one unit in the target unit; The 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.

9. The device according to claim 6, characterized in that, The discrete element analysis module includes: An acquisition unit, used to acquire the centroid coordinates of all the units to be converted, and to establish a minimum bounding box containing the centroid coordinates of all the units to be converted; A determination unit, used to determine a plurality of tetrahedrons corresponding to the centroid coordinates of all the cells to be converted in the minimum bounding box; The conversion unit is used to identify the multiple tetrahedrons as final units to be converted, and determine the rigid discrete block using the final units to be converted.

10. The device according to claim 6, characterized in that, The coupling module comprises: An identification unit, used to identify a coupling interface between a smooth point interpolation simulation region and a block discrete element simulation region in the target coal mine; An implementation unit, used for implementing coupling information transmission between the smooth point interpolation simulation area and the block discrete element simulation area; A simulation unit is used to dynamically simulate the deformation of the rock layer of the target coal mine based on the coupling interface and the coupling information transmission.

11. An electronic device, characterized in that, include: 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 any one of claims 1 to 5.

12. A computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by a processor to implement the smooth point interpolation-discrete element coupling simulation method suitable for coal mining overburden deformation as described in any one of claims 1 to 5.

13. 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 coupling simulation method suitable for overburden deformation in coal mining as described in any one of claims 1-5.

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