A three-dimensional geological modeling method for shallow seam mining based on surface topography

Abstract

This invention relates to the field of three-dimensional geological modeling technology for coal and rock strata, and particularly to a three-dimensional geological modeling method for shallow coal seam mining based on surface topography, comprising the following steps: Step 1, inputting borehole data; Step 2, establishing a database; Step 3, constructing a geological model; Step 4, converting surface models; Step 5, generating a three-dimensional solid geological model. In Step 1, data from the borehole columnar section of the study area is scanned using a scanning device, and then compiled using Excel, with different data categories placed in different Excel spreadsheets. In Step 2, the processed data is run in Accsee. This invention's method for constructing a three-dimensional numerical model of coal and rock strata based on borehole data offers fast modeling speed. By combining multiple software programs, complex borehole data and surface topography data are converted and integrated, reducing human error and enabling rapid and accurate modeling of three-dimensional geological bodies of coal and rock strata. The simulation results also conform to actual on-site production.

Description

Technical Field

[0001] This invention relates to the field of three-dimensional geological modeling technology for coal and rock strata, and in particular to a three-dimensional geological modeling method for shallow coal seam mining based on surface topography. Background Technology

[0002] Coal-bearing strata are mostly composed of sedimentary rocks. Influenced by sedimentary environments and diagenesis, coal-bearing strata commonly exhibit geological structures such as folds, faults, and pinch-outs, which significantly impact the distribution of mining-induced stress and the instability of overburden during coal seam mining. Accurately establishing a three-dimensional geological model of the coal seam and conducting numerical simulations of coal seam excavation can not only predict coal and rock damage during mining and ensure safe mining operations, but also provide engineering background and basis for intelligent mining based on transparent geology. Currently, commonly used numerical simulation software in coal seam mining, such as FLAC3D, generally simplifies the coal seam as a flat layer for simulation during the modeling process. While this modeling approach is fast, it reduces the simulation depth of the coal seam and fails to capture complex geological features, leading to significant deviations between simulation results and actual conditions. Flat-layer models cannot consider the differentiated stress distribution in the vertical direction, and the simulation results may underestimate or overestimate the stress and deformation within the coal seam, potentially leading to misjudgments of strata stability and failure mechanisms during coal seam mining. Summary of the Invention

[0003] The problem addressed by this invention is to provide a three-dimensional geological modeling method for shallow coal seam mining based on surface topography. Using borehole data and surface contour lines as basic data, the method utilizes 3DMine to establish coal and rock strata and surface DTM surfaces. These are then imported into Rhino as DXF format files, converted to NURBS surfaces, and meshed using Griddle before being imported into FLAC3D for numerical calculations. Compared to existing technologies, this method for constructing three-dimensional numerical models of coal and rock strata based on borehole data offers faster modeling speed. By combining multiple software programs to convert and interface complex borehole data with surface topography data, it reduces human error and enables rapid and accurate modeling of three-dimensional geological bodies of coal and rock strata. Furthermore, the simulation results accurately reflect actual field production conditions.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: a three-dimensional geological modeling method for shallow coal seam mining based on surface topography, comprising the following steps: Step 1, inputting borehole data; Step 2, establishing a database; Step 3, constructing a geological model; Step 4, converting surface models; Step 5, generating a three-dimensional solid geological model.

[0005] In step one, the data in the borehole column chart of the study area is scanned using a scanning device, and then compiled using Excel, with the data categorized into different Excel spreadsheets.

[0006] In step two, the processed data is run in Accsee and a database is built using 3DMine mining engineering software. After the database is built, the database and graphics are combined using 3DMine's 3D display function. Detailed information of each engineering data can be viewed intuitively. A true 3D borehole model can be obtained by setting up the 3D display of the borehole data.

[0007] In step three, the coal-bearing strata are grouped based on the borehole database of the mining area and the coal seam is used as the marker layer. Information on each coal-bearing strata is extracted according to lithology. Then, based on the information on each coal-bearing strata, the location and thickness of the roof of each coal-bearing strata are extracted to form the coordinates of the control points of the roof and floor of each coal-bearing strata. The stratigraphic modeling tool in 3DMine software is used to perform interpolation and densification of the data points using the ordinary kriging interpolation method, and the geological scatter points formed by the borehole data are quickly converted into a surface model.

[0008] In step four, 3DMine exchanges data with AutoCAD, then opens and edits the CAD drawing file, importing the surface and other files of the study area into 3DMine; the surface contour lines are converted into spatial scatter points using 3DMine's "explode" function, and then spatial interpolation is performed on the scatter points. At this time, the scatter points are densely distributed, and the inverse distance weighting method is selected for interpolation, resulting in a smoother DTM surface, thus generating the surface DTM surface;

[0009] In step five, a three-dimensional solid geological model is generated using 3DMine and Rhino in tandem. First, the top and bottom plates of each stratum and the surface are generated as dxf format files using 3DMine software and imported into Rhino. The NURBS surface is then removed using the following expression:

[0010]

[0011] In the formula, P(u) is the three-dimensional spatial coordinate of any point on the curve, di is the control vertex, Ni,k(u) is the k-th degree normalized B-spline basis function, and i is called the weight factor, which is associated with the control vertex di.

[0012] The surface model produced at this time is in the form of a triangular mesh. The curtain function in Rhino is used to convert the triangular mesh into a quadrilateral mesh. Then, the surface model is extruded to form a closed model. The extruded closed model is combined into a whole by Rhino's combination function.

[0013] Then, the Griddle modeling tool is used to generate structured and unstructured grids, and a FLAC3D three-dimensional numerical calculation model is established. For geological structures such as pinch-outs and folds between strata, the GInt, GSulf, and GVol functions in Griddle are used to create unstructured grids for pinch-out and fault strata and saved as f3grid format files that can be recognized by FLAC3D. For strata with good continuity, the BlackRanger function in Griddle is used to create structured grids and also saved as f3grid format files.

[0014] Preferably, in step one, the borehole data is divided into location attributes, lithological attributes, lateral attributes, and coal quality attributes. The location attribute table mainly records borehole engineering information, including basic information such as project number, borehole coordinates (N, E, R), maximum borehole depth, and trajectory type, as well as engineering establishment information such as tunnels and trenches. The lithological attribute table mainly records information such as descriptions of lithology and stratum thickness. The lateral attribute table mainly records information such as borehole project number, borehole footage, dip azimuth, and inclination degree. The coal quality attribute table mainly records information such as the chemical analysis results of the coal body mined from the borehole, including the air-dried basis moisture (Mad), dry basis total sulfur (Std), and dry basis higher calorific value (Qgr.d).

[0015] Preferably, in step four, Rhino is a 3D modeling software based on NURBS technology. NURBS is a mathematical representation that can accurately simulate any shape, from simple two-dimensional lines, circles, arcs, or frames to the most complex three-dimensional freeform surfaces or solids.

[0016] Preferably, in step five, the Rhino NURBS surface is the basic input data and working object for model meshing using Griddle. After Griddle completes the necessary editing of the original surface object and forms a closed surface that is impermeable, the automatic meshing operation can be performed to obtain the numerical model required for numerical analysis. The meshing of Griddle depends on the mesh shape. The numerical mesh model can be tetrahedral or hexahedral, or a mixture of both.

[0017] Preferably, in step one, the scanning device includes a scanning stage body, a moving adjustment component, an adsorption component, a placement frame, a storage frame, and scanning probes. The moving adjustment component is installed on the scanning stage body, the adsorption component is installed on the top of the scanning stage body, the placement frame is fixedly connected to the outer wall of the top of the scanning stage body, the storage frame is fixedly connected to the top of the scanning stage body at the position corresponding to the placement frame, and scanning probes are distributed and installed on the outer wall of the top of the scanning stage body, with the scanning probes located between the placement frame and the storage frame.

[0018] Preferably, the movable adjustment assembly includes a vertical plate, a guide groove, a slide groove, a motor, a lead screw, a slider, a threaded hole, a moving rod, a first spring, a moving plate, a connecting rod, a lifting block, and a first lifting hole. Vertical plates are symmetrically welded to the top outer wall of the scanning stage body. A moving plate is installed between the vertical plates. Connecting rods are fixedly connected to both outer walls of the moving plate. A guide groove is provided on the vertical plate corresponding to the position of the connecting rod. A lifting block is fixedly connected to the outer wall of one end of the connecting rod. Slide grooves are distributed at the top of the scanning stage body. A motor is embedded in the inner wall of one side of the slide groove, and one end of the motor's output shaft is fixedly connected to the lead screw, while the other end of the lead screw is rotatably connected to the inner wall of the slide groove. A slider is slidably connected within the slide groove. A threaded hole is provided on the slider corresponding to the position of the lead screw. A moving rod is fixedly connected to the top outer wall of the slider. A first lifting hole is provided on the lifting block corresponding to the position of the moving rod. A first spring is fixedly connected to the bottom outer wall of the lifting block, and the bottom end of the first spring is fixedly connected to the outer wall of the slider.

[0019] Preferably, the adsorption assembly includes a second lifting hole, a second spring, a suction cup, a lifting rod, a suction hole, a connecting plate, and a suction valve. The moving plate has the second lifting hole distributed in the distribution. A lifting rod is sleeved in the second lifting hole. A suction cup is fixedly connected to the bottom end of the lifting rod. Suction holes are respectively opened in the suction cup and the lifting rod. A suction valve is installed on the outer wall of the top end of one side of the lifting rod. A connecting plate is fixedly connected to the lifting rod. A second spring is fixedly connected to the outer wall of the bottom end of the connecting plate, and the bottom end of the second spring is fixedly connected to the outer wall of the moving plate.

[0020] Preferably, the first spring is sleeved on the outer wall of the moving rod.

[0021] Preferably, the second spring is sleeved on the outer wall of the lifting rod, and there are four second springs.

[0022] The beneficial effects of this invention are as follows: Based on borehole data and surface contour lines, a coal and rock strata and surface DTM surface are established using 3DMine, and the DXF format file is imported into Rhino and converted into a NURBS surface. Then, after meshing using Griddle, it is imported into FLAC3D for numerical calculation. Compared with the prior art, the method for constructing a three-dimensional numerical model of coal and rock strata based on borehole data has a fast modeling speed. By combining multiple software programs, complex borehole data and surface topography data are converted and integrated, reducing human error. This method can achieve rapid and accurate modeling of three-dimensional geological bodies of coal and rock strata, and the simulation results are consistent with actual field production.

[0023] It adopts a movable adjustment component, which can move and raise the document to ensure that the document can be scanned completely without manual assistance, reducing the scanning burden and improving the scanning effect;

[0024] It employs an adsorption component that can automatically adsorb documents and paper, and automatically release the adsorption after scanning, thus improving the adsorption effect. Attached Figure Description

[0025] Figure 1 This is a process flow diagram of the present invention;

[0026] Figure 2 This is a three-dimensional structural diagram of the scanning device of the present invention;

[0027] Figure 3 For the present invention Figure 2 Enlarged view of the structure of region A in the middle;

[0028] Figure 4 This is a front sectional view of the movable adjustment component of the present invention;

[0029] Figure 5 This is a front sectional view of the adsorption component of the present invention;

[0030] Figure 6 For the present invention Figure 5 Enlarged view of the structure of region B in the middle.

[0031] Legend:

[0032] 1. Scanning stage body; 2. Motion adjustment assembly; 3. Adsorption assembly; 4. Placement frame; 5. Storage frame; 6. Scanning probe; 201. Vertical plate; 202. Guide groove; 203. Slide groove; 204. Motor; 205. Lead screw; 206. Slider; 207. Threaded hole; 208. Moving rod; 209. First spring; 2010. Moving plate; 2011. Connecting rod; 2012. Lifting block; 2013. First lifting hole; 301. Second lifting hole; 302. Second spring; 303. Suction cup; 304. Lifting rod; 305. Suction hole; 306. Connecting plate; 307. Suction valve. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Example 1

[0035] See Figure 1A three-dimensional geological modeling method for shallow coal seam mining based on surface topography includes the following steps: Step 1, inputting borehole data; Step 2, establishing a database; Step 3, constructing a geological model; Step 4, converting surface models; Step 5, generating a three-dimensional solid geological model.

[0036] In step one, the data from the borehole columnar section of the study area is scanned using a scanning device, and then compiled using Excel, with different data categories placed in different Excel spreadsheets. In step one, the borehole data is divided into location attributes, lithological attributes, lateral attributes, and coal quality attributes. The location attribute table mainly records borehole engineering information, including basic information such as project number, borehole coordinates (N, E, R), maximum borehole depth, and trajectory type, as well as information related to the establishment of tunnels, trenches, and other engineering projects. The lithological attribute table mainly records information such as descriptions of lithology and stratum thickness. The lateral attribute table mainly records information such as borehole project number, borehole footage, dip azimuth, and inclination. The coal quality attribute table mainly records information such as the chemical analysis results of the coal body mined from the borehole, including the air-dried basis moisture (Mad), dry basis total sulfur (Std), and dry basis higher calorific value (Qgr.d).

[0037] In step two, the processed data is run in Accsee and a database is built using 3DMine mining engineering software. After the database is built, the database and graphics are combined using 3DMine's 3D display function. Detailed information of each engineering data can be viewed intuitively. A true 3D borehole model can be obtained by setting up the 3D display of the borehole data.

[0038] In step three, the coal-bearing strata are grouped based on the borehole database of the mining area and the coal seam is used as the marker layer. Information on each coal-bearing strata is extracted according to lithology. Then, based on the information on each coal-bearing strata, the location and thickness of the roof of each coal-bearing strata are extracted to form the coordinates of the control points of the roof and floor of each coal-bearing strata. The stratigraphic modeling tool in 3DMine software is used to perform interpolation and densification of the data points using the ordinary kriging interpolation method, and the geological scatter points formed by the borehole data are quickly converted into a surface model.

[0039] In step four, 3DMine exchanges data with AutoCAD, then opens and edits the CAD drawing file, importing the surface and other files of the study area into 3DMine; the surface contour lines are converted into spatial scatter points using 3DMine's "explode" function, and then spatial interpolation is performed on the scatter points. At this point, the scatter points are densely distributed, so choosing the inverse distance weighting method for interpolation will yield better results, making the obtained DTM surface smoother, thus generating the surface DTM surface; In step four, Rhino is a 3D modeling software based on NURBS technology. NURBS is a mathematical representation that can accurately simulate any shape from simple two-dimensional lines, circles, arcs, or frames to the most complex three-dimensional freeform surfaces or solids;

[0040] In step five, a three-dimensional solid geological model is generated using 3DMine and Rhino in tandem. First, the top and bottom plates of each stratum and the surface are generated as dxf format files using 3DMine software and imported into Rhino. The NURBS surface is then removed using the following expression:

[0041]

[0042] In the formula, P(u) is the three-dimensional spatial coordinate of any point on the curve, di is the control vertex, Ni,k(u) is the k-th degree normalized B-spline basis function, and i is called the weight factor, which is associated with the control vertex di.

[0043] The surface model produced at this time is in the form of a triangular mesh. The curtain function in Rhino is used to convert the triangular mesh into a quadrilateral mesh. Then, the surface model is extruded to form a closed model. The extruded closed model is combined into a whole by Rhino's combination function.

[0044] Then, the Griddle modeling tool is used to perform structured and unstructured mesh generation, establishing a FLAC3D three-dimensional numerical calculation model. For geological structures such as pinch-outs and folds, the GInt, GSulf, and GVol functions in Griddle are used to create unstructured meshes for pinch-out and fault strata, and saved as f3grid format files that can be recognized by FLAC3D. For strata with good continuity, the BlackRanger function in Griddle is used to create structured meshes, also saved as f3grid format files. In step five, Rhino's NURBS surface is the basic input data and working object for mesh generation in Griddle. After Griddle completes the necessary editing of the original surface object and forms a closed surface that is impermeable, the automatic mesh generation operation can be performed to obtain the numerical model required for numerical analysis. The mesh generation in Griddle depends on the mesh morphology; the numerical mesh model can be tetrahedral, hexahedral, or a mixture of both.

[0045] The structured meshes used in this process are characterized by regular connectivity between elements and typically have well-shaped cells, while unstructured meshes are identified by irregular connectivity. Compared to unstructured meshes, structured meshes provide more accurate results for stress calculations. However, in terms of generation speed, unstructured meshes are usually much faster. They can create any complex geometric model and are more effective at modeling sharper edges and corners. Therefore, this hybrid mesh modeling method combines the advantages of computational accuracy and rapid mesh generation, ensuring the construction of high-quality numerical models.

[0046] Secondly, after the numerical calculation model is established, a suitable constitutive model is selected and parameters are assigned. The initial conditions include the initial stress conditions and the initial seepage conditions. The initial stress conditions are the initial site stress generated under the action of self-weight. The aquifer simulated by the numerical calculation model is the fracture-pore water of clastic rock, that is, the water-bearing rock section located above the mining face. Its main lithology is fine sandstone. Water sources are set at each node in the aquifer. The initial seepage conditions are the pore water pressure generated under the action of gravity seepage.

[0047] Example 2

[0048] See Figures 2-4In step one, the scanning device includes a scanning stage body 1, a moving adjustment component 2, an adsorption component 3, a placement frame 4, a storage frame 5, and a scanning probe 6. The moving adjustment component 2 is installed on the scanning stage body 1, the adsorption component 3 is installed on the top of the scanning stage body 1, the placement frame 4 is fixedly connected to the outer wall of the top of the scanning stage body 1, the storage frame 5 is fixedly connected to the top of the scanning stage body 1 at the position corresponding to the placement frame 4, and the scanning probe 6 is distributed and installed on the outer wall of the top of the scanning stage body 1, and the scanning probe 6 is located between the placement frame 4 and the storage frame 5.

[0049] The movable adjustment assembly 2 includes a vertical plate 201, a guide groove 202, a slide groove 203, a motor 204, a lead screw 205, a slider 206, a threaded hole 207, a moving rod 208, a first spring 209, a moving plate 2010, a connecting rod 2011, a lifting block 2012, and a first lifting hole 2013. Vertical plates 201 are symmetrically welded to the top outer wall of the scanning stage body 1. Moving plates 2010 are installed between the vertical plates 201. Connecting rods 2011 are fixedly connected to both outer walls of the moving plates 2010. Guide grooves 202 are provided on the vertical plates 201 corresponding to the positions of the connecting rods 2011. A lifting block 2012 is fixedly connected to the outer wall of one end of the connecting rod 2011. Slide grooves 203 are distributed at the top of the scanning stage body 1. A motor 204 is embedded in the inner wall of one side of the slide groove 203, and the output of the motor 204... One end of the shaft is fixed to the lead screw 205, and the other end of the lead screw 205 is rotatably connected to the inner wall of the slide groove 203. A slider 206 is slidably connected in the slide groove 203. A threaded hole 207 is opened on the slider 206 corresponding to the position of the lead screw 205. A moving rod 208 is fixedly connected to the outer wall of the top end of the slider 206. A first lifting hole 2013 is opened on the lifting block 2012 corresponding to the position of the moving rod 208. A first spring 209 is fixedly connected to the outer wall of the bottom end of the lifting block 2012, and the bottom end of the first spring 209 is fixed to the outer wall of the slider 206. The first spring 209 is sleeved on the outer wall of the moving rod 208. When the connecting rod 2011 on the lifting block 2012 descends in an arc, the first lifting hole 2013 on the lifting block 2012 descends along the moving rod 208 under the action of the first spring 209.

[0050] Working principle: First, the paper containing the drilling data is placed inside the placement frame 4. Then, the motor 204 is started, causing the lead screw 205 to rotate. Under the action of the threaded hole 207, the slider 206 moves along the slide groove 203, driving the lifting block 2012 to move via the moving rod 208. Then, under the action of the guide groove 202, the connecting rod 2011 on the lifting block 2012 descends in an arc. Finally, under the action of the first spring 209, the first lifting hole 2013 on the lifting block 2012 moves along the moving rod 208. 08 descends, then the moving plate 2010 moves above the placement frame 4. After the document is attracted, the motor 204 is started to make the lead screw 205 rotate in the opposite direction. Then, under the action of the threaded hole 207, the slider 206 moves in the opposite direction along the slide groove 203. Then, under the action of the guide groove 202, the connecting rod 2011 on the lifting block 2012 rises in an arc. The first lifting hole 2013 on the lifting block 2012 rises along the moving rod 208, so that the moving plate 2010 moves above the storage frame 5.

[0051] Example 3

[0052] See Figures 5-6 The adsorption assembly 3 includes a second lifting hole 301, a second spring 302, a suction cup 303, a lifting rod 304, a suction hole 305, a connecting plate 306, and a suction valve 307. The moving plate 2010 has the second lifting hole 301 distributed on it. A lifting rod 304 is sleeved inside the second lifting hole 301. A suction cup 303 is fixedly connected to the bottom end of the lifting rod 304. Suction holes 305 are respectively opened inside the suction cup 303 and the lifting rod 304. A suction valve is installed on the outer wall of the top edge of one side of the lifting rod 304. A connecting plate 306 is fixedly connected to the valve 307 and the lifting rod 304. A second spring 302 is fixedly connected to the bottom outer wall of the connecting plate 306, and the bottom end of the second spring 302 is fixed to the outer wall of the moving plate 2010. The second spring 302 is sleeved on the outer wall of the lifting rod 304, and there are four second springs 302. When moving, under the action of the second springs 302 on the connecting plate 306, the lifting rod 304 on the suction cup 303 is reset along the second lifting hole 301.

[0053] When the moving plate 2010 moves above the placement frame 4, the suction cup 303 on the lifting rod 304 squeezes the document, adsorbing it, and the lifting rod 304 rises along the second lifting hole 301. At this time, the motor 204 is started, causing the lead screw 205 to rotate in the opposite direction. Then, under the action of the threaded hole 207, the slider 206 moves in the opposite direction along the slide groove 203. Then, under the action of the guide groove 202, the connecting rod 201 on the lifting block 2012... 1. The device rises in an arc, causing the first lifting hole 2013 on the lifting block 2012 to rise along the moving rod 208, so that the moving plate 2010 moves above the storage frame 5. During the movement, under the action of the second spring 302 on the connecting plate 306, the lifting rod 304 on the suction cup 303 is reset along the second lifting hole 301. At this time, the suction valve 307 is opened, and then under the action of the suction hole 305, the suction cup 303 releases its adsorption of the document, allowing the document to fall into the storage frame 5.

[0054] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A three-dimensional geological modeling method for shallow coal seam mining based on surface topography, characterized in that, Includes the following steps: Step 1: Input borehole data; Step 2: Establish database; Step 3: Construct geological model; Step 4: Convert surface model; Step 5: Generate 3D solid geological model. In step one, the data in the borehole column chart of the study area is scanned using a scanning device, and then compiled using Excel, with the data categorized into different Excel spreadsheets. In step two, the processed data is run in Accsee and a database is built using 3DMine mining engineering software. After the database is built, the database and graphics are combined using 3DMine's 3D display function. Detailed information of each engineering data can be viewed intuitively. A true 3D borehole model can be obtained by setting up the 3D display of the borehole data. In step three, the coal-bearing strata are grouped based on the borehole database of the mining area and the coal seam is used as the marker layer. Information on each coal-bearing strata is extracted according to lithology. Then, based on the information on each coal-bearing strata, the location and thickness of the roof of each coal-bearing strata are extracted to form the coordinates of the control points of the roof and floor of each coal-bearing strata. The stratigraphic modeling tool in 3DMine software is used to perform interpolation and densification of the data points using the ordinary kriging interpolation method, and the geological scatter points formed by the borehole data are quickly converted into a surface model. In step four, 3DMine exchanges data with AutoCAD, then opens and edits the CAD drawing file, importing the surface and other files of the study area into 3DMine; the surface contour lines are converted into spatial scatter points using 3DMine's "explode" function, and then spatial interpolation is performed on the scatter points. At this time, the scatter points are densely distributed, and the inverse distance weighting method is selected for interpolation, resulting in a smoother DTM surface, thus generating the surface DTM surface; In step five, a three-dimensional solid geological model is generated using 3DMine and Rhino in tandem. First, the top and bottom plates of each stratum and the surface are generated as dxf format files using 3DMine software and imported into Rhino. The NURBS surface is then removed using the following expression: In the formula, P(u) is the three-dimensional spatial coordinate of any point on the curve, di is the control vertex, Ni,k(u) is the k-th degree normalized B-spline basis function, and i is called the weight factor, which is associated with the control vertex di. The surface model produced at this time is in the form of a triangular mesh. The curtain function in Rhino is used to convert the triangular mesh into a quadrilateral mesh. Then, the surface model is extruded to form a closed model. The extruded closed model is combined into a whole by Rhino's combination function. Then, the Griddle modeling tool is used to generate structured and unstructured grids, and a FLAC3D three-dimensional numerical calculation model is established. For geological structures such as pinch-outs and folds between strata, the GInt, GSulf, and GVol functions in Griddle are used to create unstructured grids for pinch-out and fault strata and saved as f3grid format files that can be recognized by FLAC3D. For strata with good continuity, the BlackRanger function in Griddle is used to create structured grids and also saved as f3grid format files.

2. The three-dimensional geological modeling method for shallow coal seam mining based on surface topography according to claim 1, characterized in that, In step one, the borehole data is divided into location attributes, lithological attributes, lateral attributes, and coal quality attributes. The location attribute table mainly records borehole project information, including basic information such as project number, borehole coordinates (N, E, R), maximum borehole depth, and trajectory type, as well as information related to the establishment of tunnels, trenches, and other projects. The lithological attribute table mainly records information such as descriptions of lithology and stratum thickness. The lateral attribute table mainly records information such as borehole project number, borehole footage, dip azimuth, and inclination. The coal quality attribute table mainly records information such as the chemical analysis results of the coal body mined from the borehole, including the air-dried basis moisture (Mad), dry basis total sulfur (Std), and dry basis higher calorific value (Qgr.d).

3. The three-dimensional geological modeling method for shallow coal seam mining based on surface topography according to claim 1, characterized in that, In step four, Rhino is a 3D modeling software based on NURBS technology. NURBS is a mathematical representation that can accurately simulate any shape, from simple two-dimensional lines, circles, arcs, or frames to the most complex three-dimensional freeform surfaces or solids.

4. The three-dimensional geological modeling method for shallow coal seam mining based on surface topography according to claim 1, characterized in that, In step five, Rhino's NURBS surface is the basic input data and working object for model meshing using Griddle. After Griddle completes the necessary editing of the original surface object and forms a closed surface that is impermeable, the automatic meshing operation can be performed to obtain the numerical model required for numerical analysis. The meshing of Griddle depends on the mesh shape. The numerical mesh model can be tetrahedral or hexahedral, or a mixture of both.

5. The apparatus used in the three-dimensional geological modeling method for shallow coal seam mining based on surface topography according to claim 1, characterized in that, In step one, the scanning device includes a scanning stage body (1), a moving adjustment component (2), an adsorption component (3), a placement frame (4), a storage frame (5), and a scanning probe (6). The moving adjustment component (2) is installed on the scanning stage body (1). The adsorption component (3) is installed on the top of the scanning stage body (1). The placement frame (4) is fixedly connected to the outer wall of the top of the scanning stage body (1). The storage frame (5) is fixedly connected to the top of the scanning stage body (1) at the position corresponding to the placement frame (4). The scanning probe (6) is distributed and installed on the outer wall of the top of the scanning stage body (1), and the scanning probe (6) is located between the placement frame (4) and the storage frame (5).

6. The apparatus used in the three-dimensional geological modeling method for shallow coal seam mining based on surface topography according to claim 5, characterized in that, The movable adjustment assembly (2) includes a vertical plate (201), a guide groove (202), a slide groove (203), a motor (204), a lead screw (205), a slider (206), a threaded hole (207), a moving rod (208), a first spring (209), a moving plate (2010), a connecting rod (2011), a lifting block (2012), and a first lifting hole (2013). Vertical plates (201) are symmetrically welded to the top outer wall of the scanning table body (1). Moving plates (2010) are installed between the vertical plates (201). Connecting rods (2011) are fixedly connected to both outer walls of the moving plates (2010). Guide grooves (202) are provided on the vertical plates (201) corresponding to the positions of the connecting rods (2011). A lifting block (2012) is fixedly connected to the outer wall of one end of the connecting rod (2011). The scanning... The top of the drawing table body (1) is provided with a sliding groove (203). A motor (204) is embedded in the inner wall of one side of the sliding groove (203). One end of the output shaft of the motor (204) is fixed to the lead screw (205), and the other end of the lead screw (205) is rotatably connected to the inner wall of the sliding groove (203). A slider (206) is slidably connected in the sliding groove (203). A threaded hole (207) is provided on the slider (206) corresponding to the position of the lead screw (205). A moving rod (208) is fixedly connected to the top outer wall of the slider (206). A first lifting hole (2013) is provided on the lifting block (2012) corresponding to the position of the moving rod (208). A first spring (209) is fixedly connected to the bottom outer wall of the lifting block (2012), and the bottom end of the first spring (209) is fixedly connected to the outer wall of the slider (206).

7. The apparatus used in the three-dimensional geological modeling method for shallow coal seam mining based on surface topography according to claim 6, characterized in that, The adsorption assembly (3) includes a second lifting hole (301), a second spring (302), a suction cup (303), a lifting rod (304), a suction hole (305), a connecting plate (306), and a suction valve (307). The moving plate (2010) has the second lifting hole (301) distributed on it. The lifting rod (304) is sleeved in the second lifting hole (301). The bottom end of the lifting rod (304) is fixedly connected to the suction cup (307). 3) The suction cup (303) and the lifting rod (304) are respectively provided with suction holes (305). A suction valve (307) is installed on the outer wall of the top of one side of the lifting rod (304). A connecting plate (306) is fixedly connected to the lifting rod (304). A second spring (302) is fixedly connected to the outer wall of the bottom end of the connecting plate (306), and the bottom end of the second spring (302) is fixedly connected to the outer wall of the moving plate (2010).

8. The apparatus used in the three-dimensional geological modeling method for shallow coal seam mining based on surface topography according to claim 6, characterized in that, The first spring (209) is sleeved on the outer wall of the moving rod (208).

9. The apparatus used in the three-dimensional geological modeling method for shallow coal seam mining based on surface topography according to claim 7, characterized in that, The second spring (302) is sleeved on the outer wall of the lifting rod (304), and there are four second springs (302).

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