High-precision prediction method for height of two zones of coal mine roof

Abstract

The invention discloses a coal mine roof two-zone height high-precision prediction method which comprises the following steps: s1, before coal mining, obtaining a simulation result of roof two-zone height through software simulation; s2, presetting drilling parameters based on the simulation result in the step s1 and on-site conditions, and arranging a plurality of measuring drilling holes around the segmented water injection observation hole based on the drilling parameters; s3, arranging multiple stages of measuring point positions in the measuring drill hole, and installing a group of polarizability and resistivity measuring electrodes at each stage of measuring point position; s4, performing segmented water injection observation on the top plate by using a double-end plugging leak hunting device in three stages of the working face before mining, during mining and after mining, and collecting polarizability and resistivity data of each measurement point in the measurement drill hole in the process; and s5, comparing the data during or after the collection with the data before the collection of each measurement point, and determining the development height of the two zones of the roof. According to the method, the measured data is accurate and reliable, detailed information of roof change is obtained, interference of human factors is reduced, and the measurement accuracy is improved.

Description

Technical Field

[0001] The invention relates to the technical field of coal mining, and in particular to a method for high-precision prediction of two-zone heights of a coal mine roof. Background Art

[0002] In the process of coal mining, the stability and safety of the roof are crucial. The height of the two zones of the roof is directly related to the safe production of the mine. In the existing technology, geophysical exploration, drilling and other methods are usually used to measure the two zones of the roof, but these methods often have problems such as low accuracy, high cost and complex operation. Therefore, how to efficiently and accurately measure the height of the two zones of the coal mine roof has become a technical problem that needs to be solved urgently. Summary of the invention

[0003] The purpose of the present invention is to provide a high-precision prediction method for the height of two zones of coal mine roof, aiming to solve at least one of the technical problems existing in the above-mentioned prior art. To achieve the above-mentioned purpose, the technical solution adopted is as follows:

[0004] A high-precision prediction method for two-zone height of coal mine roof, the method comprising the following steps:

[0005] s1. Before coal seam mining, the deformation and destruction process of the overlying rock mass of the coal seam during mining is simulated by software to obtain the simulation results of the height of the two zones of the roof;

[0006] s2. Preset drilling parameters based on the simulation results in step s1 and the on-site conditions, and arrange multiple measurement boreholes at intervals along the circumference around the segmented water injection observation hole based on the drilling parameters;

[0007] s3. Multiple measuring points are arranged in the depth direction of the measuring borehole, and a set of polarizability and resistivity measuring electrodes are installed at each measuring point;

[0008] s4. Use a double-ended plugging leak detection device to conduct segmented water injection observation on the roof before, during and after mining. During this process, collect and measure the polarization rate and resistivity data of each measuring point in the borehole;

[0009] s5. Compare the data during or after mining at each measuring point with the data before mining to determine the development height of the two zones of the roof.

[0010] Preferably, in step s2, the distance between the measuring borehole and the segmented water injection observation hole is 1-5m.

[0011] Preferably, there are three measuring boreholes in step s2, which are used for pre-mining measurement, during-mining measurement and post-mining measurement respectively.

[0012] Preferably, in step s3, the interval between two adjacent measurement points is 1-3 m.

[0013] Preferably, the specific method for determining the development height of the two zones of the roof in step s5 is: when the data of a certain measuring point during or after mining is compared with the data before mining, the polarizability is reduced, the resistivity is increased, and there is no obvious change in the data after this measuring point, indicating that the two zones of the roof have developed to the height of this measuring point.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] (1) High precision: Through the comprehensive analysis of the two parameters of polarizability and resistivity, combined with the on-site underground segmented water injection observation results, the height of the two zones of the coal mine roof can be measured with high precision. The measurement data is accurate and reliable, and detailed information on the roof changes can be obtained, which reduces the interference of human factors and improves the accuracy of the measurement.

[0016] (2) Easy operation: The layout of measuring boreholes and measuring electrodes is relatively simple and easy to operate, which is suitable for application in the complex environment of coal mines.

[0017] (3) Data traceability: Through long-term data storage and analysis, the long-term change trends of the two zones of the roof can be predicted, providing a scientific basis for the safety management of coal mines and having practical application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the implementation mode will be briefly introduced below. Obviously, the drawings described below are only some implementation modes of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a schematic flow chart of the method of the present invention.

[0020] Figure 2 This is a numerical simulation diagram of the height of the two zones on the working face roof.

[0021] Figure 3 This is a schematic diagram of the drilling layout for working face measurement.

[0022] Figure 4 This is the polarization rate and resistivity data diagram of each measurement point before mining.

[0023] Figure 5 This is a graph of polarization rate and resistivity data at each measuring point during sampling.

[0024] Figure 6 This is the polarization rate and resistivity data diagram of each measuring point after mining. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0026] like Figure 1 As shown, a preferred embodiment of the present invention provides a method for high-precision prediction of the height of two zones of a coal mine roof, the method comprising the following steps:

[0027] s1. Numerical simulation prediction.

[0028] Before coal seam mining, the deformation and destruction process of the overlying rock mass of the coal seam during mining was simulated by 3DEC software to obtain the simulation results of the two zones of roof height.

[0029] In this example, the length of the coal mine working face is 200m. According to the relevant geological conditions of the working face, the numerical simulation results are shown in the attached figure. Figure 2 As shown, it is predicted that the final development height of the two zones of the roof will be about 68m.

[0030] s2. Lay out measuring holes.

[0031] First, a segmented water injection observation hole is arranged, specifically at a distance of about 30-33m from the cutting eye, i.e., the location of the first pressure step of mining. Segmented water injection observation of the roof is carried out through this hole, which is a commonly used two-zone height observation method.

[0032] Based on the simulation results in step s1 and the actual situation on site, the drilling parameters are preset. For example, the measured drilling depth is not less than 68m. Based on the drilling parameters, around the segmented water injection observation hole, specifically, with the segmented water injection observation hole as the center and a distance of 1-5m as the radius, in this embodiment, the radius is preferably 3 meters, and multiple measuring boreholes are arranged at equal intervals along the circumference. In this embodiment, there are preferably three measuring boreholes, which are:

[0033] Hole #1 is used for pre-mining survey, with a drilling depth of 91.5m;

[0034] Hole #2 is used for mid-mining measurement, with a drilling depth of 85.5m;

[0035] Hole #3 is used for post-mining measurement, with a drilling depth of 81.0m.

[0036] In addition, in order to ensure the accuracy of the measurement results, the elevation angles of the three measuring boreholes are consistent with the elevation angle of the segmented water injection observation hole.

[0037] s3. Install the measuring electrodes.

[0038] Multiple levels of measuring points are arranged in the three measuring boreholes #1-#3 along the depth direction. Specifically, the interval between two adjacent levels of measuring points is 1-3m, preferably 1.5m in this embodiment, and a set of polarization and resistivity measuring electrodes are installed at each level of measuring points.

[0039] s4. Collect measurement data.

[0040] The double-end plugging and leak detection device was used to conduct segmented water injection observation on the roof in the three stages before, during and after mining. During this process, the polarization rate and resistivity data of each measuring point in the borehole were collected and measured, such as Figure 3-Figure 6 shown.

[0041] s5. Determine the height of development.

[0042] Compare the data during or after mining at each measuring point with the data before mining. Specifically, when the data of a measuring point during or after mining are compared with the data before mining, the polarizability decreases and the resistivity increases, and there is no obvious change in the data after this measuring point, indicating that the two zones of the roof have developed to the height of this measuring point.

[0043] In this embodiment: after comparing with the pre-mining measurement data and analyzing the measurement data during mining, it is found that the polarization rate before the hole depth of 39m at the measuring point is reduced and the resistivity is increased. Combined with the on-site underground segmented water injection observation results, it is judged that the development height of the two zones of the roof at this time is about 31.95m. After comparing with the pre-mining measurement data and analyzing the post-mining measurement data, it is found that the polarization rate before the hole depth of 76.5m at the measuring point is reduced and the resistivity is increased. Combined with the on-site underground segmented water injection observation results, it is judged that the final development height of the two zones of the roof is 66.25m.

[0044] It should be noted that the above-mentioned two zones developed during mining at a height of 31.95m and the two zones developed after mining at a height of 66.25m are both vertical heights.

[0045] All measurement data and analysis results are entered into the database for long-term storage, and data change trends are analyzed regularly to provide a basis for mine safety management.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-precision prediction method for the height of two zones of coal mine roof, characterized in that: The method comprises the following steps: s1. Before coal seam mining, the deformation and destruction process of the overlying rock mass of the coal seam during mining is simulated by software to obtain the simulation results of the height of the two zones of the roof; s2. Preset drilling parameters based on the simulation results in step s1 and the on-site conditions, and arrange multiple measurement boreholes at intervals along the circumference around the segmented water injection observation hole based on the drilling parameters; s3. Multiple measuring points are arranged in the depth direction of the measuring borehole, and a set of polarizability and resistivity measuring electrodes are installed at each measuring point; s4. Use a double-ended plugging leak detection device to conduct segmented water injection observation on the roof before, during and after mining. During this process, collect and measure the polarization rate and resistivity data of each measuring point in the borehole; s5. Compare the data during or after mining at each measuring point with the data before mining to determine the development height of the two zones of the roof.

2. A high-precision prediction method for the height of two zones of a coal mine roof according to claim 1, characterized in that: In step s2, the distance between the measured borehole and the segmented water injection observation hole is 1-5m.

3. A high-precision prediction method for the height of two zones of coal mine roof according to claim 1, characterized in that: In step s2, there are three measurement boreholes, which are used for pre-mining measurement, mid-mining measurement and post-mining measurement respectively.

4. A high-precision prediction method for the height of two zones of a coal mine roof according to claim 1, characterized in that: In step s3, the interval between two adjacent measurement points is 1-3m.

5. A high-precision prediction method for the height of two zones of a coal mine roof according to claim 1, characterized in that: The specific method for determining the development height of the two zones of the roof in step s5 is: when the data of a certain measuring point during or after mining is compared with the data before mining, the polarizability is reduced, the resistivity is increased, and there is no obvious change in the data after this measuring point, it means that the two zones of the roof have developed to the height of this measuring point.

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