A method for constructing a virtual coal seam in an area to be mined based on small-sample local geological data

Abstract

The present invention belongs to the technical field of three-dimensional modeling and virtual simulation of coal seams, and specifically relates to a method for constructing a virtual coal seam in a mining area to be mined based on small-sample data. The method includes the following steps: S100 - obtaining coal seam edge elevation data: obtaining and saving the coal seam elevation data at the edge of the mining area to be mined from the roadways and cut-throughs around the coal seam in the mining area to be mined; S200 - constructing a digital elevation matrix: initially filling the digital elevation matrix of the coal seam model in the mining area to be mined based on the double-track sweeping principle using the coal seam elevation data obtained in S100, and then improving the accuracy of the digital elevation matrix by using the coal seam elevation information obtained from a small number of borehole samples in the middle of the coal seam; S300 - constructing a virtual coal seam that can change in real time along with virtual cutting. The present invention makes full use of the geological information of the roadways and cut-throughs, and only needs to conduct a small number of borehole surveys above the coal seam when constructing the coal seam model. The process of collecting geological data is easy to implement and has a low cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of three-dimensional modeling and virtual simulation of coal seams, and specifically relates to a method for constructing a virtual coal seam in a mining area to be mined based on small sample data. Background Art

[0002] The virtual simulation system for fully mechanized coal mining face can simulate the fully mechanized coal mining process before coal seam mining, so as to provide support for the selection of fully mechanized coal mining equipment, the layout of fully mechanized coal mining face, the design of fully mechanized coal mining process, etc. After combining with digital twin technology, it can further realize the virtual monitoring and control of the fully mechanized coal mining face, and conduct simulation research on the historical fully mechanized coal mining process after mining, which is of great significance for the realization of fully mechanized coal mining intelligence. As an important part of the virtual simulation system for fully mechanized coal mining face, constructing a virtual coal seam requires further realizing the virtual interaction between the geological environment and fully mechanized coal mining equipment on the basis of constructing a three-dimensional coal seam model. Many scholars have proposed relevant technical solutions in this technical field.

[0003] In the prior art, the invention with the application number CN201610643584.3 discloses a method for three-dimensional modeling of coal seam in working face based on geological data, and the steps include: obtaining measured geological data, data storage, interpolation operation, generating a three-dimensional coordinate database, model construction, and model update. This method can realize relatively accurate three-dimensional modeling of coal seam through sampling, interpolation of the elevation data of coal-rock interface and subsequent model update. The invention with the application number CN202010409784.9 discloses an iterative modeling method for coal seam in coal mining face under the constraint of nearly horizontal borehole trajectory. This method uses data with higher accuracy such as roadway description, inversion results of coal seam thickness by trough wave seismic exploration, and borehole trajectory to predict the coal seam morphology in the area without complex structures such as faults and collapse columns, and can realize the establishment of a relatively accurate three-dimensional model of coal seam in the mining area to be mined. The invention with the application number CN201810987960.X discloses a virtual planning method for supporting the geographical environment and equipment of fully mechanized coal mining face. This method generates a virtual coal seam model in a virtual environment using a digitalized coal seam, then imports the fully mechanized coal mining equipment model into the virtual environment for virtual simulation of the fully mechanized coal mining process, and optimizes the performance parameters using the data obtained in the simulation, and finally achieves the purpose of guiding production.

[0004] On the one hand, when constructing a deep well coal seam model using a technical solution similar to the above, a large number of deep holes or horizontal long holes need to be drilled for sampling to obtain coal seam information. In practical applications, the cost of obtaining coal seam information is relatively high or the acquisition process is rather difficult. On the other hand, there are deficiencies in the interactive design between the virtual coal seam and the fully-mechanized mining equipment in the existing virtual simulation system. That is, when simulating the cutting process, the cut roof is generated according to the cutting trajectory of the shearer after the cutting action is completed, and the virtual coal seam cannot change in a timely manner as the mining process progresses. In view of these two existing problems, the present invention proposes a method for constructing a virtual coal seam in the coal mining area to be mined based on small sample geological data. Summary of the Invention

[0005] In order to solve the above problems, the present invention provides a method for constructing a virtual coal seam in the coal mining area to be mined based on small sample data.

[0006] The present invention adopts the following technical solutions: A method for constructing a virtual coal seam in the coal mining area to be mined based on small sample data, comprising the following steps: S100 - obtaining coal seam edge elevation data: obtaining and storing the elevation data of the coal seam at the edge of the coal mining area to be mined from the roadways and cutting eyes around the coal seam in the coal mining area to be mined; S200 - constructing a digital elevation matrix: initially filling the digital elevation matrix of the coal seam model in the coal mining area to be mined based on the double-track sweeping principle using the coal seam elevation data obtained in S100, and then improving the accuracy of the digital elevation matrix by using the coal seam elevation information obtained from a small number of borehole samplings in the middle of the coal seam; S300 - constructing a virtual coal seam that can change in real time along with virtual cutting.

[0007] In step S100, the roadways include a transportation roadway and a return airway. The transportation roadway and the return airway are connected by a cutting eye, and they are arranged in parallel and are both arranged perpendicular to the cutting eye. The cutting eyes include a front cutting eye and a rear cutting eye in the coal mining area to be mined. The cutting eyes in the front and rear of the coal mining area to be mined are connected by a roadway, and they are arranged in parallel and are both arranged perpendicular to the roadway. The cutting eyes and the roadways form a rectangular passage surrounding the coal mining area to be mined. The coal seam elevation data is the elevation data of the upper and lower surfaces of the coal seam, that is, the elevation values of the upper and lower surfaces of the coal seam measured at multiple measuring points along the edge of the coal mining area to be mined and the horizontal coordinates of the corresponding measuring points.

[0008] The digital elevation matrix is a two-dimensional matrix. The positions (row numbers and column numbers) of its elements can reflect the horizontal coordinates of the corresponding nodes in the model, and the values of the elements are the elevation values of the corresponding nodes in the model. When representing the same model, the number of rows and columns of the matrix determines the node density of the model. The more the number of rows and columns of the matrix, the greater the node density of the coal seam model. The specific process of step S200 is as follows:

[0009] S210 - Initialize the digital elevation matrix: Determine the size of the digital elevation matrix according to the area of the mining area to be mined, fill the coal seam elevation data obtained in S100 into the corresponding positions of the digital elevation matrix, and leave the remaining positions empty. After filling, if there are empty positions in the first row, last row, first column, and last column of the matrix, use linear interpolation to complete these rows and columns respectively.

[0010] S220 - Initially fill the digital elevation matrix: Calculate the values of other positions in the matrix based on the first row, last row, first column, and last column of the digital elevation matrix using the double - track sweeping principle, and fill the calculation results into the digital elevation matrix.

[0011] S230 - Sample and obtain the elevation data in the middle of the coal seam: Use the digital elevation matrix initially filled in S220 for terrain analysis, conduct a small number of deep - hole sampling at key positions, and process and save the elevation data of the middle coal seam in the mining area to be mined.

[0012] S240 - Correct the digital elevation matrix: Calculate the elevation value error of the digital elevation matrix constructed in step 220 based on the elevation data of the middle coal seam obtained in S230, perform surface fitting based on these error values to obtain the residual surface function, use this function to construct the residual matrix and perform edge convergence processing on the matrix, and then add the residual matrix to the digital elevation matrix constructed in step 220 to obtain the corrected digital elevation matrix.

[0013] In step S200, based on the general law of coal seam geological changes, using the double - track sweeping principle, making the most of the limited geological data easily obtained at the roadway and cross - cut, the initial digital elevation matrix is obtained. Then, the digital elevation matrix is corrected and optimized through selective drilling, which maximally ensures the accuracy of the constructed coal seam geological model, scientifically solves the problem of difficult coal seam model establishment under limited geological exploration conditions, provides a practical and reliable new idea and new method for three - dimensional coal seam geological modeling, and is of great significance for the further development of coal mine intelligent construction.

[0014] The specific process of step S300 is as follows:

[0015] S310 - Dynamic coal seam model: Based on the digital elevation matrix constructed in step two, construct a three - dimensional coal seam model that can change in real - time with the change of the coal seam data file.

[0016] S320 - Construct a virtual coal seam: Use the monitoring data during the operation of virtual equipment to dynamically modify the coal seam model data file, and combine the process in step 310 to realize the virtual simulation of coal seam changes.

[0017] In step S210, the number of rows or columns of the digital elevation matrix should be greater than or equal to the number of measurement points in a corresponding row or column in the roadway or cross - cut described in step one.

[0018] In step S210, the linear interpolation formula for interpolation along the X-axis when initializing the digital elevation matrix is as follows:

[0019]

[0020] In the formula, x is the X coordinate of the interpolation position, x 0 is the X coordinate of the measurement point adjacent to the left of the interpolation position, x 1 is the X coordinate of the measurement point adjacent to the right of the interpolation position, z 0 is the Z coordinate of the measurement point adjacent to the left of the interpolation position, z 1 is the Z coordinate of the measurement point adjacent to the right of the interpolation position.

[0021] The linear interpolation formula for interpolation along the Y-axis when initializing the digital elevation matrix is as follows:

[0022]

[0023] In the formula, y is the Y coordinate of the interpolation position, y 0 is the Y coordinate of the measurement point adjacent to the front of the interpolation position, y 1 is the Y coordinate of the measurement point adjacent to the back of the interpolation position, z 0 is the Z coordinate of the measurement point adjacent to the front of the interpolation position, z 1 is the Z coordinate of the measurement point adjacent to the back of the interpolation position.

[0024] The form of the digital elevation matrix obtained after step S210 is as follows:

[0025]

[0026] In the formula, = 0.

[0027] The specific process of step S220 is as follows:

[0028] S221~Sweep from the four sides respectively to construct the corresponding four digital elevation matrices A1, A2, A3, and A4.

[0029] Take as the "sweeping line", and take and as the "trajectory" of the sweep. The process of double-track sweeping to construct A1 is as follows:

[0030] 1) Let A0 = A, where A is the digital elevation matrix obtained after step S210;

[0031] 2) Modify the first and last columns of the matrix A0 so that

[0032]

[0033]

[0034] 3) Based on matrix A0, calculate ,

[0035]

[0036] 4) Modify the j-th column (j = 2, 3,..., n - 1) in matrix A0 in sequence, such that

[0037]

[0038] 5) Modify in matrix A0, such that

[0039]

[0040] 6) A1 = A0; The processes of constructing A2, A3, and A4 are the same as the process of constructing A1;

[0041] S222 ~ Add the elements of A1, A2, A3, and A4 according to the element positions and weight them to obtain the final digital elevation matrix A`:

[0042]

[0043]

[0044] In the formula, 1 ≤ i ≤ m, 1 ≤ j ≤ n, 1 ≤ k ≤ 4, where i, j, k ∈ Z, is the distance from the node represented by the element in the i-th row and j-th column to the roadway or crosscut based on which matrix Ak is constructed, is the element in the i-th row and j-th column of matrix A.

[0045] In step S230, when performing terrain analysis on the digital elevation matrix constructed in step S220, first establish the elevation maps of the upper and lower surfaces of the coal seam through this digital elevation matrix, and then set borehole survey points at the middle positions of the high-convex areas and low-lying areas in the elevation maps. The borehole survey points should be set dispersedly, with 3 - 12 points per hectare.

[0046] In step S240, the elevation value errors are fitted in the form of elevation error points. Each elevation error point contains information in three dimensions: X, Y, and △Z; When fitting the residual surface function, it should be based on the elevation error points obtained from deep borehole sampling and the elevation error points with an error of 0 scattered at the edge of the coal seam. 3 - 5 elevation error points are taken per 100m at the edge of the coal seam.

[0047] In step S240, the surface fitting function is a binary quartic polynomial:

[0048]

[0049] In the formula is the coefficient to be solved, and the number of coefficients to be solved is:

[0050]

[0051] The Levenberg-Marquardt method, quasi-Newton method or differential evolution method can be selected as the fitting algorithm, and the fitting process can be implemented by 1stOpt software.

[0052] Construct a residual matrix by using the residual surface function The specific method is as follows:

[0053] f( , )

[0054] In the formula, f(x, y) is the residual surface function, is the x coordinate value corresponding to the i-th column in the digital elevation matrix, is the y coordinate value corresponding to the j-th row in the digital elevation matrix;

[0055] The specific process of edge convergence processing for the residual matrix is as follows:

[0056] When (x i , y i ) is less than M from the minimum distance D between the roadway and the crossheading, where M is 1 / 10 to 1 / 5 of the length of the roadway or crossheading, adjust R i，j as follows:

[0057]

[0058] The process of obtaining the final digital elevation matrix is as follows:

[0059]

[0060] In the formula, A`` is the final digital elevation matrix, A` is the digital elevation matrix constructed in step S220, and R is the residual matrix constructed in step S240.

[0061] Compared with the prior art, the present invention has the following beneficial effects: 1) Since the present invention makes full use of the geological information of the roadway and the cutting eye, only a small number of borehole surveys need to be carried out above the coal seam when constructing the coal seam model, and the process of collecting geological data is easy to implement and has a low cost; 2) The present invention pre-constructs an initial digital elevation matrix of the coal seam based on the double-track sweeping principle before borehole survey, and the coal seam topography information provided by this matrix provides a reliable reference basis for the selection of borehole survey positions; 3) The present invention has a low degree of data processing complexity and simple program encapsulation, and can implant the required programs or scripts into the Unity3d platform reliably and stably. Moreover, it occupies less resources during operation and has low requirements for equipment performance; 4) The present invention completes the dynamicization of the three-dimensional coal seam model and the interactive design between the coal seam and the virtual equipment based on C# scripts on the Unity3d software platform, enabling the coal seam model to change in real time as virtual mining progresses, realizing the transformation from a three-dimensional coal seam model to a virtual coal seam; 5) The present invention provides reliable virtual geological environment support for the virtual simulation system and digital twin system of the fully mechanized coal mining face, and the application process is simple and convenient, with good optimizability and integratability. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 It is a flowchart of the method of the present invention;

[0063] Figure 2 It is a schematic diagram of the method for obtaining the elevation data of the coal seam at the edge of the mining area in Step 1 of the present invention;

[0064] Figure 3 It is an example of the selection of borehole survey points in Step 301 of the present invention, where the black dots are the borehole survey points, and the contour elevation unit is meters;

[0065] Figure 4 It is the point cloud of the elevation data of the coal seam floor at the edge of the mining area in the attached example;

[0066] Figure 5 It is the point cloud of the elevation data of the coal seam roof at the edge of the mining area in the attached example;

[0067] Figure 6 It is the point cloud of the elevation data of the coal seam roof corresponding to the preliminary filling of the digital elevation matrix in the attached example;

[0068] Figure 7 It is the point cloud of the elevation data of the coal seam floor corresponding to the preliminary filling of the digital elevation matrix in the attached example;

[0069] Figure 8 It is the selection situation of borehole survey points in the attached example, and the contour elevation unit is meters;

[0070] Figure 9 It is the point cloud of the elevation data of the coal seam roof corresponding to the corrected digital elevation matrix in the attached example;

[0071] Figure 10 The coal seam floor elevation data point cloud corresponding to the corrected digital elevation matrix in the attached example;

[0072] Figure 11 The dynamic coal seam model constructed according to the digital elevation matrix in the attached example;

[0073] Figure 12 The virtual coal seam and mining equipment interaction scene constructed in Unity3d in the attached example;

[0074] Explanation of reference numerals: 1—the roof of the roadway or cut-through; 2—the floor of the roadway or cut-through; 3—the coal seam to be mined; 4—the upward borehole measurement point; 5—the direct measurement height measurement point; 6—the downward borehole measurement point. Detailed implementation manners

[0075] As Figure 1 shown, a method for constructing a virtual coal seam in a coal mining area to be mined based on small-sample geological data, and its specific implementation example includes the following steps:

[0076] S100~Obtain coal seam edge elevation data: Obtain and save the coal seam elevation data at the edge of the coal mining area to be mined from the roadways and cut-throughs around the coal seam in the coal mining area to be mined. In order to facilitate a comprehensive and intuitive display of the data, a three-dimensional point cloud method is used for display, see Figure 4 、 Figure 5 . During specific implementation, only the point cloud coordinate data needs to be obtained.

[0077] The roadway includes a transportation roadway and a return airway, and the transportation roadway and the return airway are connected by the cut-through. The two are arranged in parallel and are both arranged perpendicular to the cut-through. The cut-through includes a front-side cut-through and a rear-side cut-through in the coal mining area to be mined. The cut-throughs on the front side and the rear side of the coal mining area to be mined are connected by the roadway. The two are arranged in parallel and are both arranged perpendicular to the roadway. The cut-through and the roadway form a rectangular passage surrounding the coal mining area to be mined. The coal seam elevation data is the elevation data of the upper and lower surfaces of the coal seam, that is, the elevation values of the upper and lower surfaces of the coal seam measured at multiple measurement points along the edge of the coal mining area to be mined and the horizontal coordinates of the corresponding measurement points.

[0078] S200~Construct a digital elevation matrix: Based on the double-track sweeping principle, use the coal seam elevation data obtained in S100 to preliminarily fill the digital elevation matrix of the coal seam model in the coal mining area to be mined, and then use the coal seam elevation information obtained by a small number of borehole samplings in the middle of the coal seam to improve the accuracy of the digital elevation matrix.

[0079] The specific process is as follows:

[0080] S210 - Initialize the digital elevation matrix: Determine the size of the digital elevation matrix according to the area of the mining area to be mined, fill the coal seam elevation data obtained in step one into the corresponding positions of the digital elevation matrix, and leave the remaining positions empty. After filling, if there are empty positions in the first row, last row, first column, and last column of the matrix, use linear interpolation to complete these rows and columns respectively.

[0081] In this embodiment S210, the constructed digital elevation matrix is 86 rows and 301 columns, covering a coal seam range of 79m×150m and an area of 11,850㎡.

[0082] The digital elevation matrix obtained after S210 is in the following form:

[0083]

[0084] In the formula, = 0.

[0085] S220 - Preliminary filling of the digital elevation matrix: Calculate the values of other positions of the matrix using the first row, last row, first column, and last column of the digital elevation matrix based on the double - track sweeping principle, and fill the calculation results into the digital elevation matrix to form the corresponding data point cloud. See Figure 6 、 Figure 7 .

[0086] The specific process of step S220 is as follows:

[0087] S221 - Sweep from the four sides respectively to construct the corresponding four digital elevation matrices A1, A2, A3, and A4;

[0088] Take as the sweeping "line", and take and as the sweeping "trajectory" for the double - track sweeping to construct A1 as follows:

[0089] 1) Let A0 = A, where A is the digital elevation matrix obtained after step S210;

[0090] 2) Modify the first column and the last column in matrix A0 so that

[0091]

[0092]

[0093] 3) Based on matrix A0, calculate ,

[0094]

[0095] 4) Modify the j-th column (j = 2, 3,..., n - 1) in matrix A0 in sequence, such that

[0096]

[0097] 5) Modify in matrix A0 , such that

[0098]

[0099] 6) A1 = A0; The processes of constructing A2, A3, and A4 are the same as that of constructing A1.

[0100] S222 ~ Weighted sum the elements of A1, A2, A3, and A4 according to their positions to obtain the final digital elevation matrix A`:

[0101]

[0102]

[0103] Where 1 ≤ i ≤ m, 1 ≤ j ≤ n, 1 ≤ k ≤ 4, and i, j, k ∈ Z. is the distance from the node represented by the element in the i-th row and j-th column to the roadway or open-off cut based on which matrix Ak is constructed. is the element in the i-th row and j-th column of matrix A.

[0104] S230 ~ Sample and obtain the elevation data in the middle of the coal seam: Use the preliminarily filled digital elevation matrix for terrain analysis, conduct a small number of deep borehole samplings at key positions, process and save the elevation data of the middle coal seam in the area to be mined, see Figure 8 . When conducting terrain analysis on the digital elevation matrix constructed in step S220, first establish the elevation maps of the upper and lower surfaces of the coal seam through this digital elevation matrix respectively, and then set borehole survey points at the middle positions of the high convex areas and low-lying areas in the elevation maps.

[0105] S240 ~ Correct the digital elevation matrix: Calculate the elevation value errors of the digital elevation matrix constructed in step 220 based on the elevation data of the middle coal seam obtained in step S230, perform surface fitting based on these error values to obtain the residual surface function, use this function to construct the residual matrix and conduct edge convergence processing on the matrix. Then add the residual matrix to the digital elevation matrix constructed in step S220 to obtain the corrected digital elevation matrix, see Figure 9 、 Figure 10 .

[0106] In step S240 of this example, the elevation value error is fitted in the form of elevation error points, and each elevation error point contains information in three dimensions: X, Y, and △Z. Additionally, when fitting the residual surface function, it is based on the elevation error points obtained from deep hole sampling and the elevation error points with an error of 0 scattered at the edge of the coal seam. At the edge of the coal seam, 3 and 4 such points are evenly taken in two directions respectively (3 corresponds to the short side and 4 corresponds to the long side).

[0107] In step 240, the surface fitting function is a binary quartic polynomial:

[0108]

[0109] In the formula are the coefficients to be determined, and the number of coefficients to be determined is:

[0110]

[0111] The Marquardt method, quasi-Newton method, or differential evolution method can be selected as the fitting algorithm, and the fitting process can be implemented through 1stOpt software;

[0112] Construct a residual matrix using the residual surface function The specific method is as follows:

[0113] f( , )

[0114] In the formula, f(x,y) is the residual surface function, is the x coordinate value corresponding to the i-th column in the digital elevation matrix, is the y coordinate value corresponding to the j-th row in the digital elevation matrix;

[0115] The specific process of edge convergence processing for the residual matrix is as follows:

[0116] When (x i , y i ) is less than M from the minimum distance D between the roadway and the cut-through, where M is 1 / 10 to 1 / 5 of the length of the roadway or cut-through, make the following adjustment to R i，j :

[0117]

[0118] The process of obtaining the final digital elevation matrix is as follows:

[0119]

[0120] In the formula, A`` is the final digital elevation matrix, A` is the digital elevation matrix constructed in step 220, and R is the residual matrix constructed in step 240.

[0121] S300 - Construct a virtual coal seam that can change in real time with virtual cutting. The specific process is as follows:

[0122] S310 - Dynamic coal seam model: Based on the digital elevation matrix constructed in S200, construct a three - dimensional coal seam model in Unity3d that can change in real time with the change of the coal seam data file, as Figure 11 shown. Constructing a three - dimensional coal seam model that can change in real time with the change of the coal seam data file is mainly realized by controlling the refresh of the coal seam model based on C# code. The refresh frequency should be appropriately adjusted according to the running fluency. The key process is to use the mesh module in Unity3d and cooperate with the TIN modeling principle to construct the upper and lower surfaces of the coal seam.

[0123] S320 - Construct a virtual coal seam: Dynamically modify the coal seam model data file using the monitoring data during the operation of the virtual equipment, and combine the process in step S310 to realize the virtual simulation of the coal seam change, as Figure 12 shown. When realizing a virtual coal seam that can change in real time with virtual cutting, it is necessary to attach a C# script for collecting model data and modifying coal seam data to the virtual equipment. In addition, the equipment model and the coal seam model should both be attached with dynamic modules, rigid body modules, and collision modules in the Unity3d software.

[0124] The following will specifically explain each step:

[0125] When obtaining the elevation data of the coal seam at the edge of the mining area in S100, first rely on the three - axis space rectangular coordinate system established by the roadway and the cut - through. When obtaining the elevation data of the coal - rock interface at each measuring point in the roadway and the cut - through, when the height of the coal - rock interface at the measuring point is higher than the top height of the roadway or the cut - through, use the method of drilling upward from the inside of the roadway or the cut - through to measure the elevation value of the coal - rock interface at this measuring point; otherwise, when the height of the coal - rock interface at the measuring point is lower than the bottom height of the roadway or the cut - through, use the method of drilling downward from the inside of the roadway or the cut - through to measure the elevation value of the coal - rock interface at this measuring point; when the coal - rock interface at the measuring point can be observed inside the roadway or the cut - through, use a height - measuring device to measure the elevation value of the coal - rock interface at this measuring point. See Figure 2 . In S100, the measuring points in the roadway and the cut - through are arranged in a row or a column along the roadway and the cut - through. The measuring points should be arranged as close as possible to the edge of the coal seam in the mining area, and the distance between adjacent measuring points is 0.5m - 2m. The coal seam elevation data should be saved in the form of three - dimensional coordinate points according to the spatial arrangement order.

Claims

1. A method for constructing a virtual coal seam in a mining area to be mined based on small sample data, characterized in that: It includes the following steps, S100 ~ Obtain the elevation data of the coal seam edge: Obtain and save the elevation data of the coal seam edge in the mining area from the roadways and cutting eyes around the coal seam in the mining area to be mined; S200 ~ Construct a digital elevation matrix: Use the coal seam elevation data obtained in S100 to initially fill the digital elevation matrix of the coal seam model in the mining area to be mined based on the double-track sweeping principle, and then use the coal seam elevation information obtained by sampling a small number of boreholes in the middle of the coal seam to improve the accuracy of the digital elevation matrix; The specific process of step S200 is as follows, S210 ~ Initialize the digital elevation matrix: Determine the size of the digital elevation matrix according to the area of the mining area to be mined, fill the coal seam elevation data obtained in S100 into the corresponding positions of the digital elevation matrix, and the remaining positions are empty. After filling, if there are empty positions in the first row, last row, first column, and last column of the matrix, use linear interpolation to complete these rows and columns respectively; S220 ~ Initially fill the digital elevation matrix: Calculate the values of other positions of the matrix based on the double-track sweeping principle using the first row, last row, first column, and last column of the digital elevation matrix, and fill the calculation results into the digital elevation matrix; S230 ~ Sample and obtain the elevation data in the middle of the coal seam: Use the digital elevation matrix initially filled in S220 for terrain analysis, conduct a small number of deep borehole samplings at key positions, process and save the obtained elevation data of the coal seam in the middle of the mining area to be mined; S240 ~ Correct the digital elevation matrix: Calculate the elevation value error of the digital elevation matrix constructed in step 220 based on the coal seam middle elevation data obtained in S230, perform surface fitting based on these error values to obtain a residual surface function, use this function to construct a residual matrix and perform edge convergence processing on the matrix, and then add the residual matrix to the digital elevation matrix constructed in step 220 to obtain a corrected digital elevation matrix; S300 ~ Construct a virtual coal seam that can change in real time with virtual cutting.

2. The method for constructing a virtual coal seam in a mining area to be mined based on small sample data according to claim 1, characterized in that: The specific process of the said step S300 is as follows, S310 ~ Dynamicize the coal seam model: Based on the digital elevation matrix constructed in step two, construct a three-dimensional coal seam model that can change in real time with the change of the coal seam data file; S320 ~ Construct a virtual coal seam: Use the monitoring data during the operation of the virtual equipment to dynamically modify the coal seam model data file, and combine the process in step 310 to realize the virtual simulation of the coal seam change.

3. The method for constructing a virtual coal seam in a mining area to be mined based on small sample data according to claim 1 or 2, characterized in that: In the said step S210, the number of rows or columns of the digital elevation matrix should be greater than or equal to the number of measuring points in the corresponding row or column in the roadway or cutting eye described in step one.

4. The method for constructing a virtual coal seam in a mining area to be mined based on small sample data according to claim 3, characterized in that: In the said step S210, the linear interpolation formula for interpolation along the X-axis when initializing the digital elevation matrix is: where x is the X coordinate of the interpolation position, x 0 is the X coordinate of the measurement point adjacent to the left of the interpolation position, x 1 is the X coordinate of the measurement point adjacent to the right of the interpolation position, z 0 is the Z coordinate of the measurement point adjacent to the left of the interpolation position, z 1 is the Z coordinate of the measurement point adjacent to the right of the interpolation position; The linear interpolation formula for interpolation along the Y-axis when initializing the digital elevation matrix is as follows: Where y is the Y coordinate of the interpolation position, y 0 is the Y coordinate of the measurement point adjacent to the front of the interpolation position, y 1 is the Y coordinate of the measurement point adjacent to the back of the interpolation position, z 0 is the Z coordinate of the measurement point adjacent to the front of the interpolation position, z 1 is the Z coordinate of the measurement point adjacent to the back of the interpolation position; The form of the digital elevation matrix obtained after step 210 is as follows: Wherein, = 0.

5. The method for constructing a virtual coal seam in a mining area to be mined based on small sample data according to claim 4, characterized in that: The specific process of step S220 is as follows, S221~Sweep from four sides respectively to construct four corresponding digital elevation matrices A1, A2, A3, and A4; Take as the sweeping "line", and take and as the sweeping "trajectory" to perform the double-track sweeping to construct A1. The process is as follows: 1) Let A0 = A, where A is the digital elevation matrix obtained after step S210; 2) Modify the first column and the last column in matrix A0 so that 3) Based on matrix A0, calculate , 4) Modify the j-th column (j = 2, 3,..., n - 1) in matrix A0 in turn so that 5) Modify in matrix A0 such that 6) A1 = A0; The process of constructing A2, A3, and A4 is the same as the process of constructing A1; S222~Add the matrices A1, A2, A3, and A4 according to the element position weights to obtain the final digital elevation matrix A`: where \(1\leq i\leq m\), \(1\leq j\leq n\), \(1\leq k\leq 4\), and \(i\), \(j\), \(k\in Z\). is the distance of the node represented by the element in the \(i\)-th row and \(j\)-th column from the roadway or open-off cut based on the construction matrix \(A_k\). is the element in the \(i\)-th row and \(j\)-th column of matrix \(A\).

6. The method for constructing a virtual coal seam in a mining area to be mined based on small sample data according to claim 5, characterized in that: In step S230, when performing terrain analysis on the digital elevation matrix constructed in step S220, first establish elevation maps of the upper and lower surfaces of the coal seam through this digital elevation matrix, and then set borehole survey points at the middle positions of the high convex areas and low-lying areas in the elevation maps. The borehole survey points should be set dispersedly, with 3 to 12 points per hectare.

7. The method for constructing a virtual coal seam in a mining area to be mined based on small sample data according to claim 6, characterized in that: In step S240, the elevation value error is fitted in the form of elevation error points. Each elevation error point contains information in three dimensions: X, Y, and △Z; when fitting the residual surface function, it should be based on the elevation error points obtained from deep borehole sampling and the elevation error points with an error of 0 scattered at the edge of the coal seam. 3 to 5 elevation error points are taken every 100m at the edge of the coal seam.

8. The method for constructing a virtual coal seam in a mining area to be mined based on small sample data according to claim 7, characterized in that: In step S240, the surface fitting function is a binary quartic polynomial: wherein is the coefficient to be determined, and the number of coefficients to be determined is: The Levenberg-Marquardt method, the quasi-Newton method, or the differential evolution method can be selected as the fitting algorithm, and the fitting process can be realized through 1stOpt software; Constructing a residual matrix using a residual surface function The specific method is as follows: f( , ) where \(f(x,y)\) is the residual surface function, is the \(x\)-coordinate value corresponding to the \(i\)-th column in the digital elevation matrix, is the \(y\)-coordinate value corresponding to the \(j\)-th row in the digital elevation matrix; The specific process of performing edge convergence processing on the residual matrix is as follows: When (x i , y i ) and the minimum distance D between the roadway and the cut-through is less than M, where M is 1 / 10 to 1 / 5 of the length of the roadway or the cut-through, make the following adjustment to R i，j : The process of obtaining the final digital elevation matrix is as follows: In the formula, A`` is the final digital elevation matrix, A` is the digital elevation matrix constructed in step S220, and R is the residual matrix constructed in step S240.

9. The method for constructing a virtual coal seam in a mining area to be mined based on small sample data according to claim 1, characterized in that: In the described step S100, the roadway includes a transportation roadway and a return airway. The transportation roadway and the return airway are connected by a cutting roadway. They are arranged in parallel and both are arranged perpendicular to the cutting roadway. The cutting roadway includes a cutting roadway at the front side of the mining area to be mined and a cutting roadway at the rear side of the mining area to be mined. The cutting roadways at the front side and the rear side of the mining area to be mined are connected by a roadway. They are arranged in parallel and both are arranged perpendicular to the roadway. The cutting roadway and the roadway form a rectangular passage surrounding the mining area to be mined. The coal seam elevation data are the elevation data of the upper and lower surfaces of the coal seam, that is, the elevation values of the upper and lower surfaces of the coal seam measured at multiple measuring points along the edge of the mining area to be mined and the horizontal coordinates of the corresponding measuring points.

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