A method for monitoring mine shaft compression based on GNSS and laser ranging

Abstract

This invention discloses a method for monitoring the compression of mine shafts based on GNSS and laser ranging. It comprehensively utilizes GNSS technology, laser ranging, and multi-source data fusion algorithms. Based on the theoretical relationship between headframe settlement and the relative displacement between the headframe and the shaft opening, it constructs a shaft compression calculation model based on RTK elevation change and laser ranging change data using displacement monitoring data from GNSS and laser rangefinders. This model obtains the overall compression of the shaft and can directly acquire the millimeter-level real-time displacement evolution characteristics of the vertical shaft compression. Furthermore, it establishes a quantitative early warning threshold for the safety status of the shaft wall, providing a theoretical basis and data support for selecting the timing of shaft reinforcement and designing treatment schemes.

Description

Technical Field

[0001] This invention relates to a method for monitoring the compression of mine shafts, specifically a method for monitoring the compression of mine shafts based on GNSS and laser ranging, belonging to the field of mine safety technology. Background Technology

[0002] Mine shafts are the main entrances and exits from mines to the surface, serving as the vital arteries for hoisting and transporting coal (or gangue), personnel, materials, and equipment, as well as for ventilation and drainage during mine production. Mine shafts do not exist in isolation. When deep ore bodies are mined, the original stress balance of the overlying strata is disrupted, and stress is redistributed, causing movement and deformation of the rock mass from the goaf to the surface. As a "rigid" structure traversing the rock strata, the mine shaft will undergo vertical shortening (compression) and horizontal movement along with the surrounding rock layers.

[0003] Compression deformation of mine shafts, especially vertical shafts in deep overburden mining areas, not only reduces the cross-section of the shaft, affecting the normal operation of hoisting containers (such as cages and skips) and increasing the risk of accidents such as cage jamming and falling, but also causes the shaft wall to bear stress exceeding the design strength, leading to cracks, breakage, or even local collapse, seriously threatening the safety of underground personnel.

[0004] Understanding the overall compression of a vertical shaft is crucial for assessing its safety and developing preventative and mitigation measures for shaft wall rupture. However, current research and monitoring of shaft compression deformation, aside from reports of measured strain data in specific areas of the shaft's inner wall, lacks reports of real-time, millimeter-level separation measurements of the overall shaft compression. Existing shaft deformation monitoring methods primarily rely on strain gauges or distributed fiber optic strain monitoring systems embedded within the shaft wall to acquire strain in specific areas. These methods fail to decouple the coupling deformation between the shaft settling and shaft compression, hindering continuous measurement of the dynamic displacement of the shaft top. Furthermore, the overall shaft compression is difficult to obtain directly, failing to meet the precision requirements for continuous monitoring of vertical shaft compression and thus hindering quantitative early warning and precise mitigation of shaft rupture risks. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a method for monitoring the compression of mine shafts based on GNSS and laser ranging. This method can directly acquire the millimeter-level real-time displacement evolution characteristics of the compression of vertical shafts, thereby establishing a quantitative early warning threshold for the safety status of the shaft wall. This can provide a theoretical basis and data support for selecting the timing of shaft reinforcement and designing treatment schemes.

[0006] To achieve the above objectives, this method for monitoring mine shaft compression based on GNSS and laser ranging specifically includes the following steps:

[0007] Step 1: Install at the wellhead Each reflective target, in the corresponding Each of the reflective targets is positioned directly above a position where... The monitoring equipment includes a laser rangefinder, a dual-axis inclinometer, and a GNSS receiver; the GNSS reference station is located at a nearby national secondary reference control point;

[0008] Step 2: Data acquisition and processing are performed using RTK technology and data processing methods.

[0009] Step 3: First, the floating-point solution of the Kalman filter is obtained using the Kalman filter algorithm. Then, the LAMBDA algorithm is used to search for a set of integer ambiguity combinations in the integer space based on the floating-point solution to form a fixed solution. Finally, the coordinates of the rover station are calculated.

[0010] Step 4: Based on the coordinates of each rover station obtained in Step 3 and the known coordinates of the base station, the monitoring network joint adjustment method is used to adjust the entire network to obtain more accurate rover station coordinates, and to obtain the real-time accurate coordinates of the GNSS equipment installation location and the accurate distance measured by the laser rangefinder.

[0011] Step 5: Obtain the rotation angles around the x-axis and y-axis using each biaxial inclinometer, and then obtain the rotation matrix around the x-axis. and rotation matrix about the y-axis , means as follows:

[0012]

[0013]

[0014] In the formula: For the first The tilt angle of rotation about the x-axis, measured by a biaxial inclinometer. For the first The tilt angles about the y-axis measured by a biaxial inclinometer, where =1,2,…, ;

[0015] Then the total rotation matrix It is expressed as follows:

[0016]

[0017] In the formula: For the first A rotation matrix of a biaxial inclinometer about the x-axis. For the first A rotation matrix of a biaxial inclinometer about the y-axis, wherein... =1,2,…, ;

[0018] Finally, based on the total rotation matrix Obtain the normal vector of the top plane of the tilted derrick. ,in The total spatial skew angle of the derrick is calculated from this, and the calculation formula is as follows:

[0019]

[0020] In the formula: For the current number of The total spatial tilt angle of the derrick is calculated from the tilt angle data monitored by each monitoring device.

[0021] Step 6: First, correct the laser projection distance according to the correction formula to obtain the actual vertical displacement. The correction formula is expressed as follows:

[0022]

[0023] In the formula: For the first A laser rangefinder measured the change in vertical straight-line distance from the first monitoring to the current moment; For the first The straight-line distance between the laser rangefinder and the reflective target at the current moment, monitored by each device; For the first The vertical straight-line distance at the first monitoring of each device; The initial total spatial tilt angle of the derrick. ;

[0024] Then, the wellhead reflective target is set as the origin, and the displacement monitored by the GNSS receiver at that monitoring point is obtained. The calculation formula is as follows:

[0025]

[0026] In the formula: For the first Displacement monitored by a GNSS receiver; For the first The ordinate measured by the GNSS receiver at the current moment, as monitored by each monitoring device; For the first The ordinate measured by the GNSS receiver at the initial moment monitored by each monitoring device;

[0027] The final formula for calculating the wellbore compression is as follows:

[0028]

[0029] In the formula: For the current moment The amount of wellbore compression monitored by each monitoring device;

[0030] Step 7, for The overall wellbore compression value obtained from each monitoring device is averaged to obtain the overall wellbore compression value, as shown below:

[0031]

[0032] In the formula: This refers to the overall compression of the wellbore.

[0033] Furthermore, Step 2 is detailed below:

[0034] The pseudorange phase observation equation for RTK positioning is expressed as follows:

[0035]

[0036] In the formula: These are pseudorange observations, in meters (m). The distance between the satellite and the ground is the actual distance, in meters. Speed ​​of light, in m / s; Receiver clock bias, in seconds; Satellite clock bias, in seconds; Ionospheric delay, in meters (m). Tropospheric delay, in meters (m); The measurement noise term introduced in pseudorange observation represents the sum of all errors not directly reflected in the pseudorange phase observation equation;

[0037] The carrier phase observation equation for RTK positioning is expressed as follows:

[0038]

[0039] In the formula: Carrier phase observations, in rad; The carrier wavelength is expressed in meters (m). The integer ambiguity is expressed in rad. The measurement noise term introduced in carrier phase observation represents the sum of all errors not directly reflected in the carrier phase observation equation;

[0040] By using the pseudorange phase observation equation and carrier phase observation equation for RTK positioning, the double-difference observation equation is derived, as follows:

[0041]

[0042]

[0043] In the formula: For true double-difference pseudorange, For true double-difference satellite-to-ground distance, For true double-difference carrier phase, For double-difference integer ambiguity, where the subscript... Indicates a mobile station, subscript Indicates base station, superscript Indicates satellite superscript Indicates satellite .

[0044] Furthermore, after obtaining the rover coordinates in Step 3, the coordinate system conversion program in the GPS calculation software is used to convert them into the geodetic coordinate system.

[0045] Furthermore, in Step 1, And they are arranged in order of the four directions: east, south, west, and north.

[0046] Compared with existing technologies, this GNSS and laser ranging-based method for monitoring mine shaft compression comprehensively utilizes GNSS technology, laser ranging, and multi-source data fusion algorithms. Based on the theoretical relationship between headframe settlement and the relative displacement between the headframe and the shaft opening, it constructs a shaft compression calculation model based on RTK elevation changes and laser ranging changes using displacement monitoring data from GNSS and laser rangefinders. This model obtains the overall shaft compression and can directly acquire millimeter-level real-time displacement evolution characteristics of vertical shaft compression. Furthermore, it establishes a quantitative early warning threshold for the safety status of the shaft wall, providing a theoretical basis and data support for selecting the timing of shaft reinforcement and designing treatment schemes. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of the layout of the reflective target and monitoring equipment according to an embodiment of the present invention;

[0048] Figure 2 This is a schematic diagram illustrating the principle of calculating the derrick tilt angle according to an embodiment of the present invention;

[0049] Figure 3 This is a schematic diagram of the calculation principle of the present invention. Detailed Implementation

[0050] The present invention will be further described below with reference to the embodiments and accompanying drawings.

[0051] This method for monitoring mine shaft compression based on GNSS and laser ranging specifically includes the following steps:

[0052] Step 1: Install at the wellhead Each reflective target, in the corresponding Each of the reflective targets is positioned directly above a position where... The monitoring equipment includes a laser rangefinder, a dual-axis inclinometer, and a GNSS receiver. When deploying the reflective target and the laser rangefinder, it is necessary to ensure that the target surface and the laser lens are dust-free and dry, and at the same time, it is necessary to ensure that the reflective target is stably anchored and strictly level.

[0053] Step 2, to achieve millimeter-level data accuracy, RTK technology (Real-time kinematic, real-time dynamic differential positioning technology) and data processing methods are used for data acquisition and processing. Details are as follows:

[0054] During the data acquisition phase, positioning is achieved using the carrier phase observation equation. The pseudorange phase observation equation for RTK positioning is expressed as follows:

[0055]

[0056] In the formula: These are pseudorange observations, in meters (m). The distance between the satellite and the ground is the actual distance, in meters. Speed ​​of light, in m / s; Receiver clock bias, in seconds; Satellite clock bias, in seconds; Ionospheric delay, in meters (m). Tropospheric delay, in meters (m); This is the measurement noise term introduced in pseudorange observations, representing the sum of all errors not directly reflected in the pseudorange phase observation equations.

[0057] The carrier phase observation equation for RTK positioning is expressed as follows:

[0058]

[0059] In the formula: Carrier phase observations, in rad; The carrier wavelength is expressed in meters (m). The integer ambiguity is expressed in rad. The measurement noise term introduced in carrier phase observation represents the sum of all errors not directly reflected in the carrier phase observation equation.

[0060] In the case of short baselines (the distance between base stations and mobile stations does not exceed 10km), ionospheric and tropospheric delay errors can be eliminated, and measurement noise can be ignored.

[0061] By using the pseudorange phase observation equation and carrier phase observation equation for RTK positioning, the double-difference observation equation is derived, as follows:

[0062]

[0063]

[0064] In the formula: For true double-difference pseudorange, For true double-difference satellite-to-ground distance, For true double-difference carrier phase, For double-difference integer ambiguity, where the subscript... Indicates a mobile station, subscript The superscript indicates the base station (since the actual coordinates of the base station are known, the actual satellite-to-ground distance is assumed to be known). Indicates satellite superscript Indicates satellite .

[0065] Step 3: First, the floating-point solution of the Kalman filter is obtained using the Kalman filter algorithm. Then, the LAMBDA algorithm is used to search for the most likely combination of integer ambiguities in the integer space based on the floating-point solution to form a fixed solution. Finally, the coordinates of the rover in the WGS-84 coordinate system are calculated. As needed, the coordinate system conversion program in the GPS solution software can be used to convert it to the 2000 National Geodetic Coordinate System and other coordinate systems.

[0066] Step 4: Based on the coordinates of each rover station obtained in Step 3 and the known coordinates of the base station, the monitoring network joint adjustment method is adopted. The entire network is adjusted through baseline calculation to obtain more accurate rover station coordinates, and the real-time accurate coordinates of the GNSS equipment installation location and the accurate distance measured by the laser rangefinder are obtained.

[0067] Step 5: Obtain the rotation angles around the x-axis and y-axis using each biaxial inclinometer, and then obtain the rotation matrix around the x-axis. and rotation matrix about the y-axis , means as follows:

[0068]

[0069]

[0070] In the formula: For the first The tilt angle of rotation about the x-axis, measured by a biaxial inclinometer. For the first The tilt angles about the y-axis measured by a biaxial inclinometer, where =1,2,…, , In this case, the monitoring equipment can be arranged in the order of the four directions: east, south, west, and north.

[0071] Then the total rotation matrix It is expressed as follows:

[0072]

[0073] In the formula: For the first A rotation matrix of a biaxial inclinometer about the x-axis. For the first A rotation matrix of a biaxial inclinometer about the y-axis, wherein... =1,2,…, , In this case, they can be arranged in order according to the four directions: east, south, west, and north.

[0074] Finally, based on the total rotation matrix Obtain the normal vector of the top plane of the tilted derrick. ,in Therefore, the total tilt angle can be obtained using the formula for the angle between spatial vectors, thus obtaining the derrick deflection angle. The formula for the total tilt angle is expressed as follows:

[0075]

[0076] In the formula: For the current number of The total spatial tilt angle of the derrick is calculated from the tilt angle data monitored by each monitoring device.

[0077] Step 6: First, correct the laser projection distance according to the correction formula to obtain the actual vertical displacement. The correction formula is expressed as follows:

[0078]

[0079] In the formula: For the first A laser rangefinder measured the change in vertical straight-line distance from the first monitoring to the current moment; For the first The straight-line distance between the laser rangefinder and the reflective target (wellhead) at the current moment, monitored by each device; For the first The vertical straight-line distance at the first monitoring of each device; The initial total spatial tilt angle of the derrick is theoretically... .

[0080] Then, the wellhead reflective target is set as the origin, and the displacement monitored by the GNSS receiver at that monitoring point is obtained. The calculation formula is as follows:

[0081]

[0082] In the formula: For the first Displacement monitored by a GNSS receiver; For the first The ordinate measured by the GNSS receiver at the current moment, as monitored by each monitoring device; For the first The initial moment monitored by each monitoring device is the ordinate measured by the GNSS receiver.

[0083] The final formula for calculating the wellbore compression is as follows:

[0084]

[0085] In the formula: For the current moment The amount of wellbore compression monitored by each monitoring device.

[0086] , , All of these can be replaced with the vertical straight-line distance, derrick tilt angle, and vertical coordinate of the previous moment to calculate the displacement, angle, and ordinate within a certain time period.

[0087] Step 7, for The overall wellbore compression value obtained from each monitoring device is averaged to obtain the overall wellbore compression value, as shown below:

[0088]

[0089] In the formula: This refers to the overall compression of the wellbore.

[0090] Example:

[0091] Due to the influence of surface conditions, there are few locations available for laser rangefinder reflective targets at the wellhead. Figures 1 to 3 As shown, in this embodiment, reflective targets are positioned at the four cardinal directions (north, south, east, and west) along the outer edge of the wellhead. Correspondingly, to ensure the laser path of the laser rangefinder is vertical and unobstructed, a monitoring device is installed at each of the four cardinal directions on the top of the derrick. Each monitoring device includes a dual-axis inclinometer, a GNSS receiver, and a laser rangefinder. The dual-axis inclinometer used in this embodiment is an RS485 industrial dual-axis inclinometer. The laser rangefinder in this embodiment uses a TLS-80C high-precision laser ranging displacement sensor with a range of up to 80 meters. The GNSS receiver used in this embodiment is a Trimble R12 GNSS receiver. The GNSS reference station is located at a national secondary reference control point near the industrial site.

[0092] The monitoring equipment located in the eastern position measured , , , , , .

[0093] The monitoring equipment located in the south measured , , , , , .

[0094] The monitoring equipment located in the west measured , , , , , .

[0095] The monitoring equipment located in the north measured , , , , , .

[0096] The total spatial skew angle of the derrick is then calculated as follows:

[0097]

[0098] The change in vertical straight-line distance measured by the laser rangefinder is:

[0099]

[0100] The displacement measured by the GNSS receiver is:

[0101]

[0102] The wellbore compression measured by the monitoring equipment is:

[0103]

[0104] The overall wellbore compression calculated using the four-position monitoring equipment is then obtained as follows:

[0105]

[0106] This method for monitoring mine shaft compression based on GNSS and laser ranging can directly obtain the millimeter-level real-time displacement evolution characteristics of vertical shaft compression, thereby establishing a quantitative early warning threshold for the safety status of the shaft wall. This can provide a theoretical basis and data support for selecting the timing of shaft reinforcement and designing treatment schemes.

Claims

1. A method for monitoring mine shaft compression based on GNSS and laser ranging, characterized in that, Specifically, the following steps are included: Step 1: Install at the wellhead Each reflective target, in the corresponding Each of the reflective targets is positioned directly above a position where... The monitoring equipment includes a laser rangefinder, a dual-axis inclinometer, and a GNSS receiver; the GNSS reference station is located at a nearby national secondary reference control point; Step 2: Data acquisition and processing are performed using RTK technology and data processing methods. Step 3: First, the floating-point solution of the Kalman filter is obtained using the Kalman filter algorithm. Then, the LAMBDA algorithm is used to search for a set of integer ambiguity combinations in the integer space based on the floating-point solution to form a fixed solution. Finally, the coordinates of the rover station are calculated. Step 4: Based on the coordinates of each rover station obtained in Step 3 and the known coordinates of the base station, the monitoring network joint adjustment method is used to adjust the entire network to obtain more accurate rover station coordinates, and to obtain the real-time accurate coordinates of the GNSS equipment installation location and the accurate distance measured by the laser rangefinder. Step 5: Obtain the rotation angles around the x-axis and y-axis using each biaxial inclinometer, and then obtain the rotation matrix around the x-axis. and rotation matrix about the y-axis , means as follows: In the formula: For the first The tilt angle of rotation about the x-axis, measured by a biaxial inclinometer. For the first The tilt angles of rotation about the y-axis measured by a biaxial inclinometer, among which =1,2,…, ; Then the total rotation matrix It is expressed as follows: In the formula: For the first A rotation matrix of a biaxial inclinometer about the x-axis. For the first A rotation matrix of a biaxial inclinometer about the y-axis, wherein... =1,2,…, ; Finally, based on the total rotation matrix Obtain the normal vector of the top plane of the tilted derrick. ,in The total spatial skew angle of the derrick is calculated from this, and the calculation formula is as follows: In the formula: For the current number of The total spatial tilt angle of the derrick is calculated from the tilt angle data monitored by each monitoring device. Step 6: First, correct the laser projection distance according to the correction formula to obtain the actual vertical displacement. The correction formula is expressed as follows: In the formula: For the first A laser rangefinder measured the change in vertical straight-line distance from the first monitoring to the current moment; For the first The straight-line distance between the laser rangefinder and the reflective target at the current moment, monitored by each device; For the first The vertical straight-line distance at the first monitoring of each device; The initial total spatial tilt angle of the derrick. ; Then, the wellhead reflective target is set as the origin, and the displacement monitored by the GNSS receiver at the monitoring point is obtained. The calculation formula is as follows: In the formula: For the first Displacement monitored by a GNSS receiver; For the first The ordinate measured by the GNSS receiver at the current moment, as monitored by each monitoring device; For the first The ordinate measured by the GNSS receiver at the initial moment monitored by each monitoring device; The final formula for calculating the wellbore compression is as follows: In the formula: For the current moment The amount of wellbore compression monitored by each monitoring device; Step 7, for The overall wellbore compression value obtained from each monitoring device is averaged to obtain the overall wellbore compression value, as shown below: In the formula: This refers to the overall compression of the wellbore.

2. The method for monitoring mine shaft compression based on GNSS and laser ranging according to claim 1, characterized in that, Step 2 is as follows: The pseudorange phase observation equation for RTK positioning is expressed as follows: In the formula: These are pseudorange observations, in meters (m). The distance between the satellite and the ground is the actual distance, in meters. Speed ​​of light, in m / s; Receiver clock bias, in seconds; Satellite clock bias, in seconds; Ionospheric delay, in meters (m). Tropospheric delay, in meters (m); The measurement noise term introduced in pseudorange observation represents the sum of all errors not directly reflected in the pseudorange phase observation equation; The carrier phase observation equation for RTK positioning is expressed as follows: In the formula: Carrier phase observations, in rad; The carrier wavelength is expressed in meters (m). The ambiguity is expressed in integers, in rad. The measurement noise term introduced in carrier phase observation represents the sum of all errors not directly reflected in the carrier phase observation equation; By using the pseudorange phase observation equation and carrier phase observation equation for RTK positioning, the double-difference observation equation is derived, as follows: In the formula: For true double-difference pseudorange, For true double-difference satellite-to-ground distance, For true double-difference carrier phase, For double-difference integer ambiguity, where the subscript... Indicates a mobile station, subscript Indicates base station, superscript Indicates satellite superscript Indicates satellite .

3. The method for monitoring mine shaft compression based on GNSS and laser ranging according to claim 1 or 2, characterized in that, After obtaining the rover coordinates in Step 3, convert them to the geodetic coordinate system using the coordinate system conversion program in the GPS calculation software.

4. The method for monitoring mine shaft compression based on GNSS and laser ranging according to claim 1 or 2, characterized in that, In Step 1, And they are arranged in order of the four directions: east, south, west, and north.

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