A method for determining the range of structural stress type ore-rock movement monitored by 3D laser and GPS

Abstract

The present invention provides a method for determining the range of tectonic stress-induced ore rock movement using three-dimensional laser and GPS monitoring, comprising the following steps: first, obtaining contour lines of horizontal displacement and settlement displacement obtained from mining area monitoring; determining the surface subsidence line of the mining area based on the obtained contour lines of the tectonic stress-induced metal mining area, in combination with a horizontal deformation threshold #imgabs0#, an inclination deformation threshold #imgabs1#, and a curvature deformation threshold #imgabs2# of the surface subsidence line, and selecting the largest one as the surface subsidence line caused by mining of an underground ore body in a tectonic stress-induced metal mine; selecting a typical profile perpendicular to the goaf based on the determined surface subsidence line and the boundary of an already mined goaf in the mining area to determine the subsidence angle of the tectonic stress-induced metal mine; and delineating the surface subsidence range of a future mined ore body in the mining area based on the determined subsidence angle, thereby providing a basis for delineating the range of surface rock movement in the tectonic stress-induced metal mine.

Description

Technical Field

[0001] The present invention belongs to the field of rock movement research in mining engineering, and more specifically relates to a method for determining the range of tectonic stress-type ore rock movement using three-dimensional laser and GPS monitoring. Background Art

[0002] During the excavation of underground ore bodies in tectonic stress metal mines, as the goaf gradually grows from small to large, the surrounding rocks of the goaf are constantly unloaded, causing the surrounding rocks of the goaf to continuously move and deform. As the underground ore body is mined, this movement and deformation will gradually be transmitted to the surface, and a large subsidence basin will be formed on the surface. In addition, the existence of tectonic stress in such metal mines makes the surface subsidence basin of tectonic stress metal mines larger than that of general mines. The surface structures arranged in the mining area will suffer cracking in advance, causing serious losses to the mining area. At the same time, the larger subsidence basin will also pose a serious threat to the surrounding environment and people’s lives and property. Therefore, it is urgent to determine the surface subsidence range of tectonic stress metal mines to provide a basis for delineating the movement range of surface rock strata in tectonic stress metal mines.

[0003] A method for determining the range of tectonic stress-type rock movement using three-dimensional laser and GPS monitoring avoids the limitations of traditional GPS monitoring. To ensure human safety, traditional GPS monitoring is generally not capable of monitoring in mining subsidence areas. However, by using three-dimensional laser for non-contact monitoring in mining subsidence areas, the three-dimensional coordinates of the three-dimensional laser scanning target in the subsidence area are effectively extracted. The three-dimensional coordinates measured by GPS monitoring and the three-dimensional coordinates of the target obtained by three-dimensional laser scanning are combined, making the drawn tectonic stress-type metal mine contour lines more accurate, and thus the obtained tectonic stress-type metal mine rock stratum collapse angle is more accurate than traditional methods, achieving the purpose of effectively controlling the movement of rock strata in the mining area, and providing a basis for the layout of surface buildings and safe production in domestic tectonic stress-type metal mines. It has important theoretical significance and application value. Summary of the Invention

[0004] The present invention belongs to the field of rock movement research in mining engineering, and more specifically relates to a method for determining the range of tectonic stress-type rock movement using three-dimensional laser and GPS monitoring, which comprises the following steps:

[0005] Step 1: GPS benchmark points are deployed in an undeformed area away from the goaf of a tectonic stress metal mining area. GPS monitoring points covering the entire deformation range of the mining area are deployed in the mining area, and three-dimensional laser scanning artificial target points are deployed in the subsidence area. Data is acquired through multiple monitoring periods, including deploying a three-dimensional laser scanner at a GPS monitoring point adjacent to the subsidence area during each monitoring period, selecting a GPS monitoring point as a backsight point, and scanning and monitoring the subsidence area using a three-dimensional laser scanner to acquire point cloud scanning data. After scanning and monitoring at one GPS monitoring point, scanning is performed at the next GPS monitoring point until the entire subsidence area is scanned. GPS monitoring equipment is used to perform relative static positioning of the benchmark points and monitoring points.

[0006] Step 2: Obtain the three-dimensional coordinates of the GPS monitoring points and the three-dimensional laser scanning artificial target points in the mining area, perform displacement calculation processing, and obtain the cumulative horizontal displacement and settlement displacement of the GPS monitoring points and the three-dimensional laser scanning artificial target points during each monitoring period;

[0007] Step 3: Import the accumulated horizontal displacement and settlement displacement described in step 2 into the Surfer software, perform Kriging interpolation operation, and obtain the mining area horizontal displacement contour lines and settlement displacement contour lines of the GPS monitoring points and the three-dimensional laser scanning artificial target points during each monitoring period;

[0008] Step 4: Combine the contour lines in step 3 with the surface subsidence line according to the horizontal deformation threshold of the surface subsidence line of the metal mine. and tilt deformation threshold and curvature deformation threshold , determine the surface subsidence lines of three types of tectonic stress metal mining areas, and select the one with the largest coverage as the surface subsidence line caused by underground ore mining in tectonic stress metal mines;

[0009] Step 5. Based on the surface subsidence line described in step 4 and the boundary of the mined goaf in the mining area, select a section perpendicular to the ore body and connect it into a straight line between the boundary of the mined goaf and the surface subsidence line. The angle between this straight line and the horizontal direction is called the subsidence angle. The surface subsidence range of the ore body to be mined in the future in the mining area is delineated based on the subsidence angle.

[0010] In step 1, there are at least two GPS reference points, and any monitoring point and any two reference points should be arranged in an equilateral triangle. The GPS reference points and the GPS monitoring points should be arranged in a rock formation with a stable ground foundation. When the GPS reference points and the GPS monitoring points are used as measurement points, the angle between the line connecting the measurement point and the highest point of the obstacle and the horizontal plane between the measurement point and the obstacle does not exceed 15°. The target type used is a spherical target made of a high-reflectivity material.

[0011] The step 2 of obtaining the three-dimensional coordinates of the GPS monitoring points and the three-dimensional laser scanning artificial target points in the mining area includes:

[0012] Step 21: Based on the benchmark and projection of the tectonic stress metal mine coordinate system type in the monitoring area, the coordinate system is set by inputting these two parameters in the coordinate system of the GPS post-processing software Magnet tools. Then, the GPS data of each monitoring point is imported into the GPS post-processing software to obtain the three-dimensional coordinates of the monitoring point.

[0013] Step 22: Import the point cloud scan data into Maptek I-SiteStudio, the corresponding post-processing software for 3D laser scanning. Generate a digital elevation model of the entire mining area through station stitching, data filtering, and point cloud data thinning. Use this model to generate and export a topographic map of the entire mining area. Use CAD to extract the 3D coordinates of the artificial target points scanned by the 3D laser scanning.

[0014] Step 23: Repeat steps 21 and 22 for the point cloud scanning data and GPS data of each monitoring point obtained during each monitoring period. After data processing, the three-dimensional coordinates of the GPS monitoring points and three-dimensional laser scanning artificial target points in the mining area obtained during each monitoring period are obtained.

[0015] In step 22:

[0016] The station stitching is to input the 3D coordinates of the monitoring points and backsight points measured by the GPS observation equipment into the 3D laser scanner post-processing software Maptek I-Site Studio, so that the point cloud scan data is transferred to a common local coordinate system of the mining area. The point cloud scan data observed at different monitoring points in the mining area are stitched into a whole through rigid body transformation to obtain a point cloud data map of the entire mining area.

[0017] In station stitching, the point pair (P, Q) representing the same point on the object surface in two stations A and B satisfies the same rigid body transformation (R, T), that is:

[0018] (1)

[0019] Where P = (x p , y p , z p )∈A,Q= (x Q , y Q , z Q )∈B, R is a 3×3 rotation matrix used to describe the rotation of point Q relative to point P, and T is a 3×1 translation matrix used to describe the translation of point Q relative to point P;

[0020] The data filtering includes three types: isolated point filtering, terrain filtering, and intensity filtering. Isolated point filtering is used to remove noise points in the scan data; terrain filtering is used to remove data points that are not related to the terrain; and intensity filtering is to filter data points based on the intensity information of the laser reflection.

[0021] The point cloud data thinning is used to simplify the point cloud data.

[0022] In step 2, the displacement calculation process is performed to obtain the cumulative horizontal displacement and settlement displacement of the GPS monitoring point and the 3D laser scanning artificial target point during each monitoring period, including:

[0023] Assume that the three-dimensional coordinates of the GPS monitoring point m obtained in the first monitoring or the artificial target point m obtained by three-dimensional laser scanning are (x m1 , y m1 , z m1 ), the three-dimensional coordinates of the GPS monitoring point m obtained by the i-th monitoring or the artificial target point m obtained by three-dimensional laser scanning are (x mi , y mi , z mi ), the two coordinates are subtracted to obtain the cumulative horizontal displacement in the orthogonal direction of the GPS monitoring point m or target point m in the i-th monitoring (h mix = x mi -x m1 , h miy = y mi -y m1 ) and cumulative settlement displacement (V mi =z mi -z m1 ), where the cumulative horizontal displacement is

[0024] .

[0025] The Kriging interpolation operation performed in step 3 includes:

[0026] First, group the data points into equal intervals according to the known intervals between them;

[0027] The semivariogram function is then applied to each group to obtain a set of discrete known data points

[0028] , these known data points describe the semivariance of data point pairs at different distances, and we get

[0029] ,

[0030] Based on known data points and known data points The semivariance value calculated by the distance between them reflects the spatial correlation between known data points;

[0031] The semivariogram function is:

[0032] (2)

[0033] in:

[0034] Represents the estimated value of the semivariogram function, which is used to describe the distance between two data points in space. The average of the squares of the differences between their observations is used to measure the autocorrelation of spatial data. and They are located at and The observed value of

[0035] Indicates that the distance interval The number of data points within represents the average distance between point pairs, Represents a data point pair and the distance between them;

[0036] Calculate the unknown points to be estimated The semivariogram function value between the known data points is obtained. ;

[0037] Then, the Kriging formula (3) is used to obtain the value of each known data point for the unknown point. Weight of the semivariogram function value ;

[0038] (3)

[0039] in: Represents a known point For unknown points The unknown quantity c is a constant about the Lagrange multiplier to ensure unbiasedness;

[0040] Using weights and known data points The eigenvalue of To estimate the unknown point The eigenvalue of ;

[0041] (4)

[0042] Formula (4) is the constructed semivariogram model: eigenvalue and It is the cumulative horizontal displacement and settlement displacement of known points and unknown points. The known data points are GPS monitoring points and artificial target points obtained by 3D laser scanning.

[0043] The step 4 comprises:

[0044] Step 41: Calculate the deformation difference between adjacent horizontal displacement contour lines:

[0045] , calculate the deformation difference between adjacent settlement displacement contour lines: ;

[0046] and are the horizontal displacement values of the adjacent horizontal displacement contour line n and horizontal displacement contour line n+1 respectively; W n and W n+1 are the settlement displacement values of the adjacent settlement displacement contour line n and settlement displacement contour line n+1 respectively;

[0047] Step 42: According to the horizontal deformation threshold The deformation difference between the horizontal displacement contour line and the surface limit horizontal length corresponding to the deformation difference is calculated. , according to the tilt deformation threshold The deformation difference between the displacement contour line and the settlement displacement contour line is used to calculate the surface limit tilt length corresponding to the deformation difference. , then the surface limit horizontal length and the surface extreme tilt length Set the diameters to draw the first movable circle and the second movable circle respectively;

[0048] Step 43: Move the first movable circle to all positions between the adjacent nth and n+1th horizontal displacement contour lines. If the center of the first movable circle is moved to any position where the first movable circle is tangent to the adjacent nth and n+1th horizontal displacement contour lines, mark the center of the circle at that position as the horizontal sink line threshold point.

[0049] Move the second movable circle to all positions between the adjacent nth and n+1th settlement displacement contour lines. If the center of the second movable circle is moved to any position where the second movable circle is tangent to the adjacent nth and n+1th settlement displacement contour lines, then mark the center of the circle at that position as the settlement line threshold point.

[0050] Step 44: Repeat steps 41 to 43 to mark all sink line threshold points between two adjacent horizontal displacement or settlement displacement contour lines; then connect all horizontal sink line threshold points using a spline curve to obtain the surface sink line of the tectonic stress type metal mining area corresponding to the horizontal displacement;

[0051] All the subsidence line threshold points are connected by spline curves to obtain the surface subsidence line of the tectonic stress type metal mining area corresponding to the subsidence displacement;

[0052] Step 45: Select a surface monitoring point on the settlement and displacement contour line of the tectonic stress type metal mine that intersects a section parallel to the direction of the goaf and perpendicular to the direction of the goaf. According to the settlement and displacement contour line, the settlement and displacement of different surface monitoring points on the section are obtained. The curvature deformation value k at each surface monitoring point on the section is calculated. If the curvature deformation value of a surface monitoring point on the section is Curvature deformation threshold If the absolute value of the difference is the smallest, the surface monitoring point is determined to be the location of the critical deformation of the curvature on the profile;

[0053] Step 46: Repeat step 45 to construct multiple sections and mark the critical deformation position of curvature on each section. Connect the critical deformation positions of curvature of all sections with spline curves to form a curve based on curvature deformation. Determined surface subsidence line of tectonic stress type metal mine;

[0054] mm / m,

[0055] mm / m,

[0056] / m.

[0057] Curvature deformation corresponding to surface monitoring point m+1

[0058] It refers to the ratio of the difference in inclination between adjacent line segments to the horizontal distance between the midpoints of the two segments;

[0059] (5)

[0060] Refers to the horizontal distance between adjacent surface monitoring points m+1 and m+2;

[0061] Refers to the horizontal distance between adjacent surface monitoring points m and m+1;

[0062] represents the average tilt deformation between adjacent surface monitoring points m+1 and m+2,

[0063] represents the average tilt deformation between adjacent surface monitoring points m and m+1;

[0064] Tilt deformation Calculated according to formula (6), it refers to the ratio of the vertical subsidence difference between two adjacent surface monitoring points m and m+1 to their horizontal distance, reflecting the slope of the surface movement basin along a certain direction;

[0065] (6)

[0066] Where,

[0067] Refers to the horizontal distance between adjacent surface monitoring points m and m+1; W m and W m+1 are the settlement displacements of the adjacent surface monitoring point m and surface monitoring point m+1 respectively;

[0068] Represents the average tilt deformation between adjacent surface monitoring points m and m+1.

[0069] The smaller the collapse angle is, the larger the surface collapse range caused by underground mining will be. In addition, the surface collapse range of the future mining body can be delineated based on the determined collapse angle of the tectonic stress type metal mine.

[0070] The beneficial effects of the present invention are: a method for determining the range of tectonic stress-type ore rock movement using three-dimensional laser and GPS monitoring avoids the limitations of traditional GPS monitoring, and effectively extracts the three-dimensional coordinates of the target in the collapse area by using three-dimensional laser for non-contact monitoring in the mining collapse area. The three-dimensional coordinates measured by GPS monitoring and the three-dimensional coordinates of the target obtained by three-dimensional laser scanning are combined, so that the drawn tectonic stress-type metal mine contour lines are more accurate, and the obtained tectonic stress-type metal mine rock stratum collapse angle is more accurate than that determined by traditional methods, providing a basis for the layout of surface buildings and safe production in domestic tectonic stress-type metal mines, and having important theoretical significance and application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Figure 1 This is a flow chart of a method for determining the range of tectonic stress-induced rock movement using three-dimensional laser and GPS monitoring. Figure 2 It is the horizontal displacement contour map of the mining area;

[0072] Figure 3 It is the contour map of mining area settlement and displacement;

[0073] Figure 4 It is the mining area subsidence line formed by connecting the first movable circles between the mining area horizontal displacement contour lines;

[0074] Figure 5 A mining area subsidence line map determined based on horizontal deformation;

[0075] Figure 6The subsidence line map of the mining area determined based on settlement deformation;

[0076] Figure 7 The mining area subsidence line map is determined based on curvature deformation;

[0077] Figure 8 This is the mining area subsidence line map;

[0078] Figure 9 This is the collapse angle diagram of the mining area perpendicular to the goaf section. DETAILED DESCRIPTION

[0079] In order to make the purpose, technical solutions and advantages of the embodiments of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0080] The positioning type adopted by GPS is a high-precision, stable relative static positioning technology. This positioning technology is a satellite positioning method that measures the relative positions between multiple measuring stations. It can significantly reduce the impact of positioning deviations caused by the clock deviation of the receiving device, the deviation of the satellite trajectory, and the refraction of the ionosphere and troposphere, thereby improving positioning accuracy.

[0081] Example 1

[0082] S01. Deploy GPS benchmarks in the undeformed area away from the goaf of the tectonic stress metal mining area. At the same time, deploy GPS monitoring points covering the entire deformation range of the mining area. Arrange 3D laser scanning artificial target points in the subsidence area.

[0083] Among them, at least two GPS reference points are required, and the number of GPS monitoring points can be arranged according to the monitoring range of the mining area. Any monitoring point and any two reference points should be arranged in an equilateral triangle; GPS reference points and GPS monitoring points should be arranged in rock formations with stable ground foundations, and GPS reference points and GPS monitoring points should be used as measuring points. The angle between the line from the measuring point to the highest point of the obstacle and the horizontal plane between the measuring point and the obstacle shall not exceed 15°; the target type used is a spherical target made of high-reflectivity material to ensure strong reflection of the three-dimensional laser signal and improve the target recognition rate and positioning accuracy.

[0084] S02. Because the GPS benchmark is far from the subsidence area, the 3D laser scanner cannot identify and locate it. Therefore, during monitoring, a 3D laser scanner is first deployed at a GPS monitoring point adjacent to the subsidence area. One GPS monitoring point is selected as the backsight point to scan and monitor the subsidence area, acquiring point cloud scan data. After scanning one GPS monitoring point, scanning can be performed at the next GPS monitoring point until the entire subsidence area has been scanned. GPS monitoring equipment is then used to monitor the GPS monitoring points. During monitoring, two GPS observation devices are permanently fixed at the GPS benchmark points as control points. Additional GPS observation devices are installed at GPS monitoring points during each time period to monitor deformation and acquire GPS data from each monitoring point. Each GPS observation device observes each measurement point for at least 60 minutes, with at least four valid satellites simultaneously observing. During GPS monitoring, the GPS monitoring point where the 3D laser scanner is deployed and the backsight point used for orientation and positioning are first monitored, followed by measurements of the remaining GPS monitoring points.

[0085] The backsight point is a point with known coordinates used to determine the position and orientation of the 3D laser scanner. The backsight point is usually a target point or a prism. The backsight point is placed at a position that the 3D laser scanner can identify and measure, so as to be used for orientation and positioning during the scanning process.

[0086] The steps for scanning and monitoring at the GPS monitoring point specifically include: during three-dimensional laser scanning, the three-dimensional laser scanner is set up on a tripod connected to the base of the three-dimensional laser scanner at the GPS monitoring point adjacent to the collapse area, the entire three-dimensional laser scanner is leveled and the measurement mark of the GPS monitoring point is centered. Since the reference point is relatively far away from the collapse area, the three-dimensional laser scanner cannot recognize and locate it. A GPS monitoring point with a better field of view is selected as the backsight point of the three-dimensional laser scanning, and the center of the crosshairs on the eyepiece of the three-dimensional laser scanner is aligned with the measurement mark on the GPS backsight point. Finally, the range to be scanned is selected on the handbook and the scanning point cloud density is selected according to the accuracy required by the mining area, and the scanning begins.

[0087] S03. Setting the coordinate system in the GPS post-processing software Magnet Tools according to the benchmark and projection parameters of the tectonic stress type metal mine coordinate system in the monitoring area, then importing the GPS data of each monitoring point into the GPS post-processing software to obtain the three-dimensional coordinates (x, y, z) of the monitoring point;

[0088] S04. Import the point cloud scan data into Maptek I-Site Studio, a 3D laser point cloud post-processing software. Generate a digital elevation model (DEM) of the entire mining area through the following processing: station stitching, data filtering, and point cloud data thinning. Generate a topographic map of the entire mining area from the DEM model. Then, export the topographic map in CAD format from Maptek I-Site Studio, and use CAD to extract the 3D coordinates of the artificial target points from the 3D laser scan.

[0089] Station stitching is the process of inputting the 3D coordinates (x, y, z) of the monitoring points and backsight points measured by GPS observation equipment into Maptek I-Site Studio, a 3D laser scanner post-processing software, so that the point cloud scan data is transferred to a common local coordinate system of the mining area. Through rigid body transformation, the point cloud scan data observed at different monitoring points in the mining area are stitched into a whole to obtain a point cloud data map of the entire mining area.

[0090] In the station splicing, the point pair (P, Q) representing the same point on the object surface in the two stations A and B satisfies the same rigid body transformation (R, T), that is,

[0091] (1)

[0092] Where P = (x p , y p , z p )∈A,Q= (x Q , y Q , z Q )∈B, R is a 3×3 rotation matrix used to describe the rotation of point Q relative to point P, and T is a 3×1 translation matrix used to describe the translation of point Q relative to point P.

[0093] Data filtering includes three types: isolated point filtering, terrain filtering, and intensity filtering. Isolated point filtering is mainly used to remove noise points in the scan data; terrain filtering is mainly used to remove data points that are not related to the terrain, such as vegetation, buildings, etc.; intensity filtering filters data points based on the intensity information of laser reflection.

[0094] Point cloud data thinning is used to further streamline point cloud data and improve processing efficiency.

[0095] S05. Assume that the three-dimensional coordinates of the GPS monitoring point m obtained by the first monitoring or the artificial target point m obtained by three-dimensional laser scanning are (x m1 , y m1 , z m1 ), the three-dimensional coordinates of the GPS monitoring point m obtained by the i-th monitoring or the artificial target point m obtained by three-dimensional laser scanning are (x mi , ymi , z mi ), the two coordinates are subtracted to obtain the cumulative horizontal displacement in the orthogonal direction of the GPS monitoring point m or target point m during the i-th monitoring period (h mix = x mi -x m1 , h miy = y mi -y m1 ) and cumulative settlement displacement (V mi =z mi -z m1 ), where the cumulative horizontal displacement is

[0096] , the vector direction is determined according to the displacement magnitude in the x-direction and the y-direction; after multiple observations, the cumulative horizontal displacement and settlement displacement in each monitoring period of the mining area can be obtained;

[0097] S06, the cumulative horizontal displacement Hmn and settlement displacement Vmn of the GPS monitoring point m or target point m obtained in the nth monitoring and the plane coordinates (x mn , y mn ) is imported into Surfer software, and the Kriging interpolation method in Surfer software is used to obtain the mining area horizontal displacement contour line and settlement displacement contour line obtained by the nth monitoring of the mining area, and the horizontal displacement and settlement displacement contour line in CAD format are exported from Surfer ( Figure 2 and Figure 3 ); The smaller the interval between the horizontal displacement and settlement displacement contour lines generated by surfer, the more accurate the location of the surface subsidence line.

[0098] Kriging interpolation is a geostatistical method used to predict the value of an unknown point based on known data points. This method is widely used in fields such as geology, environmental science, and agriculture. Kriging interpolation is based on the correlation between existing, scattered, measured data points, where the correlation between these points depends solely on the distance between them. The semivariogram (Semivariogram) is a key tool used in Kriging interpolation to describe the spatial correlation between data points, as shown below:

[0099] (2)

[0100] in: Represents the estimated value of the semivariogram function, which is used to describe the distance between two data points in space. The average of the squares of the differences between their observations is used to measure the autocorrelation of spatial data. and They are located at and The observed value of Indicates that the distance interval The number of data points within

[0101] represents the average distance between point pairs, Represents a data point pair and The distance between them.

[0102] Use Kriging interpolation to estimate the measured points The eigenvalues on The method comprises the following steps:

[0103] First, group the data points into equal intervals according to the known intervals between them;

[0104] Then apply the semivariogram function (Formula 2) to each group to obtain a set of discrete known data points , these known data points describe the semivariance of data point pairs at different distances. , Based on known data points and known data points The semivariance value calculated by the distance between them reflects the spatial correlation between known data points;

[0105] Calculate the unknown points to be estimated The semivariogram function value between the known data points is obtained. ;

[0106] Then, the Kriging formula (3) is used to obtain the value of each known data point for the unknown point. Weight of the semivariogram function value ;

[0107] (3)

[0108] in: Represents a known point For unknown points The unknown quantity c is a constant about the Lagrange multiplier to ensure unbiasedness.

[0109] Using these weights and known data points The eigenvalue of To estimate the unknown point The eigenvalue of ;

[0110] (4)

[0111] Formula (4) is the constructed semivariogram model: eigenvalue T and It is the cumulative horizontal displacement and settlement displacement of known and unknown points. Known data points are GPS monitoring points and artificial target points obtained by 3D laser scanning.

[0112] S07, based on the horizontal deformation threshold of the surface subsidence line of the metal mine and tilt deformation threshold , and combined with the deformation value difference between the horizontal displacement and settlement displacement contour lines, calculate the surface limit horizontal length corresponding to the deformation value difference, which is used to draw a circle to determine the deformation threshold of the sinking line;

[0113] S071. If the difference in deformation between the adjacent nth and n+1th horizontal displacement contour lines of the mine is 4 cm, set the horizontal deformation threshold is 6 mm / m, so there are 4 cm / = =6mm / m, calculate the maximum horizontal length of the ground surface =6.67m); Similarly, the difference in deformation between the adjacent nth and n+1th settlement displacement contour lines of the mine is , set the horizontal deformation threshold is 10 mm / m, so there are 4 cm / = =6mm / m, the determined surface limit tilt length 4 m;

[0114] S072. Then, the surface limit horizontal length and the surface extreme tilt length Set the diameters to draw the first movable circle and the second movable circle respectively;

[0115] S073. The first movable circle (such as Figure 4 The red circle shown in FIG1 is moved to all positions between the adjacent nth and n+1th horizontal displacement contour lines. If the center of the first movable circle moves to any position where the first movable circle is tangent to the adjacent nth and n+1th horizontal displacement contour lines, the center of the circle at that position is marked as the threshold point of the horizontal sink line.

[0116] Move the second movable circle to all positions between the adjacent nth and n+1th settlement displacement contour lines. If the center of the second movable circle is moved to any position where the second movable circle is tangent to the adjacent nth and n+1th settlement displacement contour lines, then mark the center of the circle at that position as the settlement line threshold point.

[0117] S074. Finally, repeat steps S071 to S073 to mark all the sink line threshold points between two adjacent horizontal displacement or settlement displacement contour lines. From the contour lines of horizontal displacement and settlement displacement, many sink line threshold points can be obtained. Then, spline curves are used to connect the sink line threshold points of horizontal displacement and settlement displacement respectively.

[0118] and tilt deformation threshold The surface subsidence line of the tectonic stress metal mining area corresponding to the horizontal displacement and settlement displacement is obtained ( Figure 5 The blue curve and Figure 6 The red curve in );

[0119] S08. Select the surface monitoring points that intersect the sections parallel to and perpendicular to the goaf on the settlement and displacement contour lines of the tectonic stress type metal mine. Obtain the settlement and displacement values of different surface monitoring points on the section according to the settlement and displacement contour lines. Calculate the curvature deformation value k at each surface monitoring point on the section. If the curvature deformation value of a surface monitoring point on the section is

[0120] Curvature deformation threshold The absolute value of the difference is the smallest, then the surface monitoring point is determined to be the location of the critical deformation of the curvature on the profile, and the locations of the critical deformation of the curvature of all profiles are connected with spline curves to form a curve based on the curvature deformation. Determined surface collapse line of tectonic stress metal mine ( Figure 7 green curve);

[0121] Curvature deformation Calculate as follows:

[0122] (5)

[0123] Refers to the horizontal distance between adjacent surface monitoring points m+1 and m+2;

[0124] Refers to the horizontal distance between adjacent surface monitoring points m and m+1;

[0125] represents the average tilt deformation between adjacent surface monitoring points m+1 and m+2,

[0126] represents the average tilt deformation between adjacent surface monitoring points m and m+1;

[0127] Curvature deformation corresponding to surface monitoring point m+1

[0128] It refers to the ratio of the difference in inclination between adjacent line segments to the horizontal distance between the midpoints of the two segments.

[0129] Tilt deformation

[0130] Calculated according to formula (6), it refers to the ratio of the vertical subsidence difference between two adjacent surface monitoring points m and m+1 to their horizontal distance, reflecting the slope of the surface movement basin along a certain direction;

[0131] (6)

[0132] Where,

[0133] Refers to the horizontal distance between adjacent surface monitoring points m and m+1; W m and W m+1 are the settlement displacements of the adjacent surface monitoring point m and surface monitoring point m+1 respectively;

[0134] represents the average tilt deformation between adjacent surface monitoring points m and m+1;

[0135] The deformation threshold of the sink line is:

[0136] mm / m,

[0137] mm / m,

[0138] / m

[0139] S09, according to the deformation threshold of the sink line 、 and Among the three surface subsidence lines identified, the one with the largest coverage is selected as the surface subsidence line caused by the underground ore body of the tectonic stress type metal mine. According to the comparison, it can be seen that the horizontal deformation Determined maximum;

[0140] like Figure 8 As shown, the blue, red and green trap lines are respectively 、 and k, so horizontal deformation is selected The determined collapse line is used as the surface collapse line caused by the underground ore body in the tectonic stress type metal mine;

[0141] S10, based on the surface collapse line of the tectonic stress metal mine obtained in step S09, select a section perpendicular to the ore body and connect it from the boundary of the mined goaf to the surface collapse line to form a straight line. The angle between the straight line and the horizontal direction is called the collapse angle ( Figure 9 ), with the hanging wall at 55° and the footwall at 65°. This collapse angle can be used to determine the extent of subsidence caused by underground mining in tectonic stress-induced metal mining areas. The smaller the rock formation collapse angle, the greater the extent of surface subsidence caused by underground mining. For example, if the hanging wall of a mine has a larger collapse area than the footwall, the determined collapse angle can be used to delineate the extent of surface subsidence in future mining operations.

[0142] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for determining the range of tectonic stress-type rock movement using three-dimensional laser and GPS monitoring, characterized in that: The steps include: Step 1: GPS benchmark points are deployed in an undeformed area away from the goaf of a tectonic stress metal mining area. GPS monitoring points covering the entire deformation range of the mining area are deployed in the mining area, and three-dimensional laser scanning artificial target points are deployed in the subsidence area. Data is acquired through multiple monitoring periods, including deploying a three-dimensional laser scanner at a GPS monitoring point adjacent to the subsidence area during each monitoring period, selecting a GPS monitoring point as a backsight point, and scanning and monitoring the subsidence area using a three-dimensional laser scanner to acquire point cloud scanning data. After scanning and monitoring at one GPS monitoring point, scanning is performed at the next GPS monitoring point until the entire subsidence area is scanned. GPS monitoring equipment is used to perform relative static positioning of the benchmark points and monitoring points. Step 2: Obtain the three-dimensional coordinates of the GPS monitoring points and the three-dimensional laser scanning artificial target points in the mining area, perform displacement calculation processing, and obtain the cumulative horizontal displacement and settlement displacement of the GPS monitoring points and the three-dimensional laser scanning artificial target points during each monitoring period; Step 3: Import the accumulated horizontal displacement and settlement displacement described in step 2 into the Surfer software, perform Kriging interpolation operation, and obtain the mining area horizontal displacement contour lines and settlement displacement contour lines of the GPS monitoring points and the three-dimensional laser scanning artificial target points during each monitoring period; Step 4: Based on the horizontal deformation threshold of the surface subsidence line of the metal mine and tilt deformation threshold and curvature deformation threshold , and combined with the horizontal displacement and settlement displacement contour lines described in step 3, determine the surface subsidence lines of the three tectonic stress type metal mining areas, and select the one with the largest coverage as the surface subsidence line caused by underground ore body mining in the tectonic stress type metal mine; Step 5. Based on the surface subsidence line described in step 4 and the boundary of the mined goaf in the mining area, select a section perpendicular to the ore body and connect it into a straight line between the boundary of the mined goaf and the surface subsidence line. The angle between this straight line and the horizontal direction is called the subsidence angle. The surface subsidence range of the ore body to be mined in the future in the mining area is delineated based on the subsidence angle.

2. The method according to claim 1, characterized in that In step 1, there are at least two GPS reference points, and any monitoring point and any two reference points should be arranged in an equilateral triangle. The GPS reference points and the GPS monitoring points should be arranged in a rock formation with a stable ground foundation. When the GPS reference points and the GPS monitoring points are used as measurement points, the angle between the line connecting the measurement point and the highest point of the obstacle and the horizontal plane between the measurement point and the obstacle does not exceed 15°. The target type used is a spherical target made of a high-reflectivity material.

3. The method according to claim 1, characterized in that The step 2 of obtaining the three-dimensional coordinates of the GPS monitoring points and the three-dimensional laser scanning artificial target points in the mining area includes: Step 21: Based on the benchmark and projection of the tectonic stress metal mine coordinate system type in the monitoring area, the coordinate system is set by inputting these two parameters in the coordinate system of the GPS post-processing software Magnet tools. Then, the GPS data of each monitoring point is imported into the GPS post-processing software to obtain the three-dimensional coordinates of the monitoring point. Step 22: Import the point cloud scan data into Maptek I-Site Studio, the corresponding post-processing software for 3D laser scanning. Generate a digital elevation model of the entire mining area through station stitching, data filtering, and point cloud data thinning. Use this model to generate and export a topographic map of the entire mining area. Use CAD to extract the 3D coordinates of the artificial target points scanned by the 3D laser scanning. Step 23: Repeat steps 21 and 22 for the point cloud scanning data and GPS data of each monitoring point obtained during each monitoring period. After data processing, the three-dimensional coordinates of the GPS monitoring points and three-dimensional laser scanning artificial target points in the mining area obtained during each monitoring period are obtained.

4. The method according to claim 3, characterized in that In step 22: The station stitching is to input the 3D coordinates of the monitoring points and backsight points measured by the GPS observation equipment into the 3D laser scanner post-processing software Maptek I-Site Studio, so that the point cloud scan data is transferred to a common local coordinate system of the mining area. The point cloud scan data observed at different monitoring points in the mining area are stitched into a whole through rigid body transformation to obtain a point cloud data map of the entire mining area. In station stitching, the point pair (P, Q) representing the same point on the object surface in two stations A and B satisfies the same rigid body transformation (R, T), that is: (1) Where P = (x p , y p , z p )∈A,Q= (x Q , y Q , z Q )∈B, R is a 3×3 rotation matrix used to describe the rotation of point Q relative to point P, and T is a 3×1 translation matrix used to describe the translation of point Q relative to point P; The data filtering includes three types: isolated point filtering, terrain filtering, and intensity filtering. Isolated point filtering is used to remove noise points in the scan data; terrain filtering is used to remove data points that are not related to the terrain; and intensity filtering is to filter data points based on the intensity information of the laser reflection. The point cloud data thinning is used to simplify the point cloud data.

5. The method according to claim 3, characterized in that In step 2, the displacement calculation process is performed to obtain the cumulative horizontal displacement and settlement displacement of the GPS monitoring point and the 3D laser scanning artificial target point during each monitoring period, including: Assume that the three-dimensional coordinates of the GPS monitoring point m obtained in the first monitoring or the artificial target point m obtained by three-dimensional laser scanning are (x m1 ,y m1 , z m1 ), the three-dimensional coordinates of the GPS monitoring point m obtained by the i-th monitoring or the artificial target point m obtained by three-dimensional laser scanning are (x mi , y mi , z mi ), the two coordinates are subtracted to obtain the cumulative horizontal displacement h in the orthogonal direction of the GPS monitoring point m or target point m in the i-th monitoring mix = x mi -x m1 , h miy = y mi -y m1 and cumulative settlement displacement V mi =z mi -z m1 , where the cumulative horizontal displacement is 。 6. The method according to claim 1, characterized in that The Kriging interpolation operation performed in step 3 includes: First, group the data points into equal intervals according to the known intervals between them; The semivariogram function is then applied to each group to obtain a set of discrete known data points , these known data points describe the semivariance of data point pairs at different distances, and we get ， Based on known data points and known data points The semivariance value calculated by the distance between them reflects the spatial correlation between known data points; The semivariogram function is: (2) in: Represents the estimated value of the semivariogram function, which is used to describe the distance between two data points in space. The average of the squares of the differences between their observations is used to measure the autocorrelation of spatial data. and They are located at and The observed value of Indicates that the distance interval The number of data points within represents the average distance between point pairs, Represents a data point pair and Calculate the distance between unknown points to be estimated The semivariogram function value between the known data points is obtained. ; Then, the Kriging formula (3) is used to obtain the value of each known data point for the unknown point. Weight of the semivariogram function value ; （3） in: Represents a known point For unknown points The unknown quantity c is a constant about the Lagrange multiplier to ensure unbiasedness; Using weights and known data points The eigenvalue of To estimate the unknown point The eigenvalue of ; (4) Formula (4) is the constructed semivariogram model: eigenvalue is the cumulative horizontal displacement and settlement displacement of the known point, the eigenvalue It is the cumulative horizontal displacement and settlement displacement of the unknown point. The known data points are GPS monitoring points and artificial target points obtained by 3D laser scanning.

7. The method according to claim 1, characterized in that The step 4 comprises: Step 41: Calculate the deformation difference between adjacent horizontal displacement contour lines: , calculate the deformation difference between adjacent settlement displacement contour lines: ； and are the horizontal displacement values of the adjacent horizontal displacement contour line n and horizontal displacement contour line n+1 respectively; W n and W n+1 are the settlement displacement values of the adjacent settlement displacement contour line n and settlement displacement contour line n+1 respectively; Step 42: According to the horizontal deformation threshold The deformation difference between the horizontal displacement contour line and the surface limit horizontal length corresponding to the deformation difference is calculated. , according to the tilt deformation threshold The deformation difference between the displacement contour line and the settlement displacement contour line is used to calculate the surface limit tilt length corresponding to the deformation difference. , then the surface limit horizontal length and the surface extreme tilt length Set the diameters to draw the first movable circle and the second movable circle respectively; Step 43: Move the first movable circle to all positions between the adjacent nth and n+1th horizontal displacement contour lines. If the center of the first movable circle is moved to any position where the first movable circle is tangent to the adjacent nth and n+1th horizontal displacement contour lines, mark the center of the circle at that position as the horizontal sink line threshold point. Move the second movable circle to all positions between the adjacent nth and n+1th settlement displacement contour lines. If the center of the second movable circle is moved to any position where the second movable circle is tangent to the adjacent nth and n+1th settlement displacement contour lines, then mark the center of the circle at that position as the settlement line threshold point. Step 44: Repeat steps 41 to 43 to mark all sink line threshold points between two adjacent horizontal displacement or settlement displacement contour lines; then connect all horizontal sink line threshold points using a spline curve to obtain the surface sink line of the tectonic stress type metal mining area corresponding to the horizontal displacement; All the subsidence line threshold points are connected by spline curves to obtain the surface subsidence line of the tectonic stress type metal mining area corresponding to the subsidence displacement; Step 45: Select a surface monitoring point on the settlement and displacement contour line of the tectonic stress type metal mine that intersects a section parallel to the direction of the goaf and perpendicular to the direction of the goaf. According to the settlement and displacement contour line, the settlement and displacement of different surface monitoring points on the section are obtained. The curvature deformation value k at each surface monitoring point on the section is calculated. If the curvature deformation value of a surface monitoring point on the section is Curvature deformation threshold If the absolute value of the difference is the smallest, the surface monitoring point is determined to be the location of the critical deformation of the curvature on the profile; Step 46: Repeat step 45 to construct multiple sections and mark the critical deformation position of curvature on each section. Connect the critical deformation positions of curvature of all sections with spline curves to form a curve based on curvature deformation. Determined surface subsidence line of tectonic stress type metal mine; mm / m, mm / m, / m。 8. The method according to claim 7, characterized in that Curvature deformation corresponding to surface monitoring point m+1 It refers to the ratio of the difference in inclination between adjacent line segments to the horizontal distance between the midpoints of the two segments; (5) Refers to the horizontal distance between adjacent surface monitoring points m+1 and m+2; Refers to the horizontal distance between adjacent surface monitoring points m and m+1; represents the average tilt deformation between adjacent surface monitoring points m+1 and m+2, represents the average tilt deformation between adjacent surface monitoring points m and m+1; Average tilt deformation Calculated according to formula (6), it refers to the ratio of the vertical subsidence difference between two adjacent surface monitoring points m and m+1 to their horizontal distance, reflecting the slope of the surface movement basin along a certain direction; (6) Where, Refers to the horizontal distance between adjacent surface monitoring points m and m+1; W m and W m+1 are the settlement displacements of the adjacent surface monitoring point m and surface monitoring point m+1 respectively; Represents the average tilt deformation between adjacent surface monitoring points m and m+1.

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