A method for determining the stability time of the roof of a coal mine goaf with rock burst

Abstract

The application discloses a kind of rock burst mine goaf roof stability time determination method, comprising: obtaining different advancing stages of working face trend and tendency support stress influence range and microseismic activity influence range, and taking greater value as the working face different stage trend and tendency mining stress influence range;Based on the working face different stage trend and tendency mining stress influence range, system analysis is carried out to obtain the goaf low roof stability time and the goaf high roof stability time;Comprehensive comparison low roof stability time and high roof stability time, take greater value as goaf roof stability time.The rock burst mine goaf roof stability time determination method involved in the application is more in line with the actual situation of mine, and the accuracy of the obtained roof stability time is higher, which provides more accurate and powerful reference for the management of goaf in later stage of mine and the design of working face connection.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of roof stability evaluation of rock burst goaf, and particularly relates to a method for determining roof stability time of rock burst goaf in a mine. BACKGROUND

[0002] As the main energy in China, coal will maintain a high yield in a period of time under the background of the rapid development of the national economy. With the shift of the focus of coal production to the deep part in China, the coal mine roadway shows the characteristics of high ground stress, low surrounding rock strength and soft and broken, the risk of rock burst disaster is increasing, and it has become one of the main disasters restricting the safe and efficient production of the mine. Rock burst generally releases elastic energy rapidly in a sharp and violent form when the coal and rock mass reaches the limit of failure strength, which causes damage to mine equipment, and even causes casualties to workers and huge economic and property losses to the society.

[0003] After the safe mining of the working face in the rock burst mine, the stability of the roof of the goaf is still an important hidden problem. The formation of a large range of goaf makes the roof suspend in a large area, and the sudden roof breakage can cause a huge energy release, which causes great interference to the surrounding mining and excavation operations, even destroys the surrounding rock stability of the operation area, and causes serious rock burst accidents, equipment damage and casualties. Therefore, it is urgent to solve the problem of accurately evaluating the stability of the roof of the rock burst goaf and obtaining the roof stability time. It is also the premise and guarantee to ensure the safe and efficient production of the rock burst mine working face. SUMMARY

[0004] The purpose of the present application is to provide a method for determining the roof stability time of the rock burst goaf in a mine, which solves the problems existing in the prior art.

[0005] To achieve the above purpose, the present application provides a method for determining the roof stability time of the rock burst goaf in a mine, which comprises:

[0006] obtaining the influence range of the abutment stress in the direction of the working face and the tendency in different advancing stages;

[0007] obtaining the influence range of the microseismic activity in the direction of the working face and the tendency in different advancing stages;

[0008] based on the influence range of the abutment stress and the influence range of the microseismic activity, obtaining the influence range of the mining stress in the direction of the working face and the tendency in different advancing stages;

[0009] based on the influence range of the mining stress, analyzing the attenuation characteristics of the microseismic frequency, total energy and mining time, and obtaining the stability time of the low position roof of the goaf;

[0010] Based on the analysis of the influence range of the mining-induced stress, the decay characteristics of the surface subsidence rate and the mining time are obtained to determine the stabilization time of the high-level roof in the goaf.

[0011] By comprehensively comparing the stabilization time of the low-level roof of the goaf with the stabilization time of the high-level roof of the goaf, the maximum value is taken as the stabilization time of the roof of the goaf.

[0012] Optionally, the process of obtaining the influence range of the support stress includes: obtaining a comprehensive columnar section of the working face and physical and mechanical parameters of the coal and rock mass; constructing a three-dimensional numerical model; excavating the three-dimensional numerical model according to the actual mining speed of the working face; extracting the support stress data in front of and laterally at the working face advancement position; defining the initial support stress influence range of the working face strike and dip as the distance between the advancement position and the support stress reduction to the original stress position of the coal seam; setting the support stress influence range influence coefficient based on the actual geological structure conditions of the working face, special geological conditions, and mining conditions; and obtaining the final support stress influence range based on the initial support stress influence range and the support stress influence range influence coefficient. The support stress influence range influence coefficient is taken as 1.02 to 1.22.

[0013] Optionally, the process of obtaining the influence range of the microseismic activity includes: acquiring microseismic data during the longwall mining process, processing and analyzing the microseismic data to obtain microseismic location maps at different mining stages, and based on the microseismic location maps, determining a range greater than or equal to 10. 3 J microseismic events or more than 3 events with a magnitude of less than 10 3 The distance from the microseismic event cluster area to the working face advancement position is the initial microseismic activity influence range. Based on the layout of the microseismic stations at the working face and special geological and mining conditions, an influence coefficient for the microseismic activity influence range is set. The final microseismic activity influence range is obtained based on the initial microseismic activity influence range and the influence coefficient. The influence coefficient for the microseismic activity influence range is taken as 1.01 to 1.21.

[0014] Optionally, by comprehensively comparing the influence range of the support stress and the influence range of the microseismic activity, the larger value is taken as the basis, and adjustments are made based on the actual geological structure conditions, special geological conditions and mining conditions of the working face, to obtain the influence range of the stress on the direction and tendency of the working face at different advancement stages.

[0015] Optionally, the process for obtaining the stable time of the low position roof of the goaf comprises: obtaining microseismic activities in the corresponding mining stress influence range after the end of the mining of different stages of the working face, statistically analyzing the microseismic activities, dividing the frequency and total energy of the microseismic activities into different levels respectively, statistically analyzing the time required for the microseismic activities in the corresponding mining stress influence range after the end of the mining of different stages of the working face to reach the corresponding level, considering that the low position roof of the goaf reaches basic stability when the microseismic frequency is reduced to 5 times per day and the total energy is reduced to 3.0 KJ or less, considering that the basic stability accumulates for the initial stable time of the low position roof of the goaf, setting a low position roof activity stable time coefficient based on the working face microseismic station arrangement, special geology and mining conditions, and obtaining the final stable time of the low position roof of the goaf based on the initial stable time of the low position roof of the goaf and the low position roof activity stable time coefficient. The low position roof activity stable time coefficient is 1.1-1.2.

[0016] Optionally, the process for obtaining the stable time of the high position roof of the goaf comprises: obtaining the surface subsidence value in the corresponding mining stress influence range after the end of the mining of different stages of the working face, statistically analyzing the surface subsidence value, dividing the surface subsidence speed into different levels, statistically analyzing the time required for the surface subsidence speed in the corresponding mining stress influence range after the end of the mining of different stages of the working face to reach the corresponding level, considering that the high position roof of the goaf reaches basic stability when the surface subsidence speed is reduced to 1.0 mm per day or less, considering that the basic stability accumulates for the initial stable time of the high position roof of the goaf after the end of the mining of the working face, setting a high position roof activity stable time coefficient based on the working face surface subsidence monitoring station arrangement, special geology and mining conditions, and obtaining the final stable time of the high position roof of the goaf based on the initial stable time of the high position roof of the goaf and the high position roof activity stable time coefficient. The high position roof activity stable time coefficient is 1.05-1.25.

[0017] Optionally, the microseismic data is analyzed in an analysis stage of every 5 days.

[0018] Optionally, the microseismic activities are statistically analyzed in an analysis stage of every 5 days.

[0019] Optionally, the surface subsidence value is statistically analyzed in an analysis stage of every 15-30 days.

[0020] The technical effect of the present application is:

[0021] The method for determining the roof stable time of the goaf of the rock burst mine involved in the present application is more in line with the actual situation of the mine, and the obtained roof stable time has higher accuracy, thereby providing a more accurate and powerful reference basis for the management of the goaf and the design of the connection of the working face in the later stage of the mine. BRIEF DESCRIPTION OF DRAWINGS

[0022] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0023] Figure 1 This is a flowchart illustrating the method for determining the stabilization time of the roof in a goaf of a mine affected by rock bursts, as described in this embodiment of the invention.

[0024] Figure 2 Figure (a) shows the micro-seismic positioning plan of the 6301 working face in the embodiments of the present invention, Figure (b) shows the micro-seismic positioning plan of the working face after 20m of mining, Figure (c) shows the micro-seismic positioning plan of the working face after 100m of mining, Figure (d) shows the micro-seismic positioning plan of the working face after 140m of mining, Figure (e) shows the micro-seismic positioning plan of the working face after 180m of mining, and Figure (f) shows the micro-seismic positioning plan of the working face after 220m of mining. Detailed Implementation

[0025] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0026] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0027] Example 1

[0028] like Figure 1 As shown in the figure, this embodiment provides a method for determining the stabilization time of the roof in the goaf of a rockburst mine, including:

[0029] Obtain the direction and influence range of the bearing stress at different stages of the working face's advancement;

[0030] Obtain the trajectory and potential range of microseismic activity at different stages of the working face's advancement;

[0031] Based on the influence range of support stress and the influence range of microseismic activity, the influence range of mining stress at different stages of the working face is obtained;

[0032] Based on the analysis of the influence range of mining-induced stress, the attenuation characteristics of microseismic frequency, total energy and mining time are obtained to determine the stabilization time of the low-level roof in the goaf.

[0033] Based on the analysis of the influence range of mining-induced stress, the decay characteristics of surface subsidence velocity and mining time are obtained to determine the stabilization time of the high-level roof in the goaf.

[0034] By comprehensively comparing the stabilization time of the low-level roof and the high-level roof in the goaf, the maximum value is taken as the stabilization time of the roof in the goaf.

[0035] As one implementation method, the process of obtaining the influence range of bearing stress includes: acquiring the comprehensive columnar section of the working face and the physical and mechanical parameters of the coal and rock mass; constructing a three-dimensional numerical model; excavating the three-dimensional numerical model according to the actual mining speed of the working face; extracting the bearing stress data in front of and laterally at the working face advancement position; defining the initial bearing stress influence range of the working face strike and dip as the distance between the advancement position and the bearing stress reduction to the original stress position of the coal seam; setting the bearing stress influence range influence coefficient based on the actual geological structure conditions of the working face, special geological conditions, and mining conditions; and obtaining the final bearing stress influence range based on the initial bearing stress influence range and the bearing stress influence range influence coefficient. The bearing stress influence range influence coefficient is taken as 1.02 to 1.22.

[0036] As one implementation method, the process of obtaining the influence range of microseismic activity includes: acquiring microseismic data during the longwall mining process, processing and analyzing the microseismic data to obtain microseismic location maps at different mining stages, and based on the microseismic location maps, determining the influence range of microseismic activity greater than or equal to 10. 3 J microseismic events or more than 3 events with a magnitude of less than 10 3 The distance from the microseismic event cluster area to the working face advancement position is the initial microseismic activity influence range. Based on the layout of the microseismic stations at the working face and special geological and mining conditions, an influence coefficient for the microseismic activity influence range is set. The final microseismic activity influence range is obtained based on the initial microseismic activity influence range and the influence coefficient. The influence coefficient for the microseismic activity influence range is taken as 1.01 to 1.21.

[0037] As one implementation method, the influence range of support stress and the influence range of microseismic activity are comprehensively compared, and the larger value is taken as the basis. Adjustments are made based on the actual geological structure conditions, special geological conditions and mining conditions of the working face to obtain the influence range of mining stress in different stages of the working face.

[0038] As an implementation form, the process of obtaining the stable time of the low position roof of the goaf includes: obtaining microseismic activities in the corresponding stress influence range of the working face after different stages of mining, statistically analyzing the microseismic activities, dividing the frequency and total energy of the microseismic activities into different levels respectively, statistically analyzing the time required for the microseismic activities in the corresponding stress influence range of the working face after different stages of mining to reach the corresponding level, considering that the low position roof of the goaf is basically stable when the microseismic frequency is reduced to 5 times per day and the total energy is reduced to 3.0 KJ or less, considering that the initial stable time of the low position roof of the goaf is the total number of days accumulated in the basic stability, setting a stable time coefficient of the low position roof activity based on the arrangement of the microseismic station of the working face, special geology and mining conditions, and obtaining the final stable time of the low position roof of the goaf based on the initial stable time of the low position roof of the goaf and the stable time coefficient of the low position roof activity. The stable time coefficient of the low position roof activity is 1.1-1.2.

[0039] As an implementation form, the process of obtaining the stable time of the high position roof of the goaf includes: obtaining the surface subsidence value in the corresponding stress influence range of the working face after different stages of mining, statistically analyzing the surface subsidence value, dividing the surface subsidence speed into different levels, statistically analyzing the time required for the surface subsidence speed in the corresponding stress influence range of the working face after different stages of mining to reach the corresponding level, considering that the high position roof of the goaf is basically stable when the surface subsidence speed is reduced to 1.0 mm per day or less, considering that the initial stable time of the high position roof of the goaf after the mining of the working face is the total number of days accumulated in the basic stability, setting a stable time coefficient of the high position roof activity based on the arrangement of the surface subsidence monitoring station of the working face, special geology and mining conditions, and obtaining the final stable time of the high position roof of the goaf based on the initial stable time of the high position roof of the goaf and the stable time coefficient of the high position roof activity. The stable time coefficient of the high position roof activity is 1.05-1.25.

[0040] As an implementation form, the microseismic data is analyzed every 5 days as an analysis stage.

[0041] As an implementation form, the microseismic activities are statistically analyzed every 5 days as an analysis stage.

[0042] As an implementation form, the surface subsidence value is statistically analyzed every 15-30 days as an analysis stage.

[0043] Example two

[0044] As shown in Figure 1 The embodiment provides a method for determining the stable time of the roof of the goaf of a rock burst mine, which includes:

[0045] obtaining the stress influence range of the working face in different advancing stages

[0046] Obtaining the microseismic activity influence range of the working face in different advancing stages in the strike and inclination directions;

[0047] Based on the support stress influence range and the microseismic activity influence range, obtaining the mining stress influence range of the working face in different advancing stages in the strike and inclination directions;

[0048] Based on the mining stress influence range, analyzing the attenuation characteristics of the microseismic frequency, total energy and recovery time, and obtaining the stable time of the low-position roof of the goaf;

[0049] Based on the mining stress influence range, analyzing the attenuation characteristics of the surface subsidence speed and recovery time, and obtaining the stable time of the high-position roof of the goaf;

[0050] Comprehensively comparing the stable time of the low-position roof of the goaf and the stable time of the high-position roof of the goaf, taking the maximum value as the stable time of the roof of the goaf.

[0051] In this embodiment, the evaluation of the support stress influence range of the working face in different advancing stages in the strike and inclination directions includes:

[0052] The comprehensive columnar diagram of the 6301 working face and the physical and mechanical parameters of the coal and rock mass are collected, and the mechanical property parameters of the coal seam are shown in Table 1. In order to comprehensively and systematically reflect the mining stress distribution characteristics of the 6301 working face in different advancing stages, a FLAC3D three-dimensional geological model is established for numerical simulation based on the geological and mining technical conditions of the 630 working face. The model is 1400m long along the strike, 1200m wide along the inclination, and 272m high.

[0053] Table 1

[0054]

[0055] According to the actual mining and excavation connection situation of the 630 mining area, the model is excavated to fully simulate the stress environment conditions before the mining of the 6301 working face. According to the actual recovery speed of about 2m / day of the 6301 working face, the 6301 working face is excavated, and the support stress influence range of the working face in different stages is shown in Table 2.

[0056] Table 2

[0057]

[0058] Considering that numerical simulation cannot fully restore the actual geological structure conditions (to some extent, it will cause the influence distance of the strike and inclination support stress not to be accurate enough in the numerical simulation process, thereby affecting data analysis), the influence range safety factor of the strike and inclination support stress can be set. According to the actual geological structure conditions of the working face, special geology, mining conditions and the like, the safety factor can be taken as 1.25. In summary, it can be considered that the maximum influence distances of the strike and inclination support stress during the recovery process of the 6301 working face are 225 m and 100 m, respectively.

[0059] In this embodiment, the influence range of the microseismic activity of the working face in different stages includes:

[0060] The microseismic events of the 6301 working face from August 2019 to January 2020 are analyzed for positioning, and the microseismic positioning diagram of some stages of the working face is shown in FIG. 2. Figure 2 According to the microseismic positioning results, the distance from the aggregation area of the microseismic events greater than or equal to J or more than 3 microseismic events less than J to the working face advancing position is the microseismic activity range of the working face in the stage, and the statistical situation of the microseismic activity range of the 6301 working face is shown in Table 3.

[0061] Table 3

[0062]

[0063] Meanwhile, considering the influence of other factors such as the improper arrangement of the working face microseismic station (to some extent, it will cause the microseismic positioning error, thereby affecting data analysis), the safety factor of the microseismic activity range can be set. According to the arrangement of the working face microseismic station, special geology, mining conditions and the like, the safety factor can be taken as 1.15 (the coefficient is formulated by referring to the practical experience of related mines). In summary, it can be considered that the maximum influence distances of the strike and inclination microseismic activity during the recovery process of the 6301 working face are 274 m and 110 m, respectively.

[0064] In this embodiment, the influence range of the mining-induced stress of the working face in different stages includes:

[0065] The influence distances of the strike and inclination support stress and microseismic in different stages of the working face are compared and analyzed, and the influence range of the mining-induced stress of the working face in different stages is determined comprehensively. The influence range of the mining-induced stress of the 6301 working face in different stages is shown in Table 4.

[0066] Table 4

[0067]

[0068] In this embodiment, based on the influence range of mining stress in different stages of the working face, the attenuation characteristics of microseismic frequency, total energy and mining time in the region are analyzed to obtain the stable time of the low roof in the goaf, which includes:

[0069] The microseismic activities in the corresponding roof influence range after the end of mining in different stages of the working face are statistically analyzed every five days. The frequency and total energy occurring in this period are divided into four levels of 75 times / day, 50 times / day, 25 times / day, 5 times / day and 30KJ, 21KJ, 12KJ, 3KJ respectively. With five days as a mining stage, it is considered that the low roof in the goaf is basically stable when the microseismic frequency is reduced to 5 times and the total energy is reduced to 3.0KJ after the end of mining in different stages of the working face. The total number of days accumulated is the stable time of the low roof in the goaf after the end of mining in the working face. The stable time of the low roof in different stages of 6301 working face is shown in Table 5.

[0070] Table 5

[0071]

[0072] Meanwhile, considering the influence of other factors such as improper arrangement of microseismic station in the working face (which will cause positioning error of microseismic to some extent, thereby affecting data analysis), the stable time coefficient of overburden activity can be set. According to the arrangement of microseismic station in the working face, special geology and mining conditions, etc., the time coefficient can be taken as 1.25. In summary, it can be considered that the low roof in 6301 working face needs at least 188 days to reach a stable state after the end of mining.

[0073] In this embodiment, based on the influence range of mining stress in different stages of the working face, the attenuation characteristics of surface subsidence speed and mining time in the region are analyzed to obtain the stable time of the high roof in the goaf, which includes:

[0074] The surface subsidence value in the corresponding roof influence range after the end of mining in different stages of the working face is statistically analyzed every fifteen days. The surface subsidence speed in this period is divided into five levels of 5mm / day, 4mm / day, 3mm / day, 2mm / day, 1mm / day. With fifteen days as a mining stage, it is considered that the high roof in the goaf is basically stable when the surface subsidence speed is reduced to 1.0mm / day or less after the end of mining in different stages of the working face. The total number of days accumulated is the stable time of the high roof in the goaf after the end of mining in the working face. The stable time of the high roof in different stages of 6301 working face is shown in Table 6.

[0075] Table 6

[0076]

[0077] Meanwhile, considering other factors such as improper arrangement of the working face surface subsidence monitoring station (which will cause statistical error of subsidence value to some extent, thereby affecting data analysis), a time coefficient of overburden activity stability can be set, and according to the arrangement of the working face surface subsidence monitoring station, special geology and mining conditions, etc., the time coefficient can be 1.05. In summary, it can be considered that the low roof of the 6301 working face needs at least 221 days to basically reach a stable state after the end of the mining.

[0078] The application provides a method for determining the stability time of the roof of a goaf in a rock burst mine, which evaluates the influence range of the strike and dip support stress and the influence range of the microseismic activity at different advancing stages of the working face, takes the larger value as the influence range of the mining stress in the strike and dip direction at different stages of the working face, analyzes the attenuation characteristics of the microseismic frequency, total energy and mining time in the region based on the influence range of the mining stress in the strike and dip direction at different stages of the working face, to obtain the stability time of the low roof of the goaf, analyzes the attenuation characteristics of the surface subsidence speed and mining time in the region based on the influence range of the mining stress in the strike and dip direction at different stages of the working face, to obtain the stability time of the high roof of the goaf, and compares the stability time of the low roof of the goaf and the stability time of the low roof of the goaf, and takes the larger value as the stability time of the roof of the goaf. The method for determining the stability time of the roof of the goaf in the rock burst mine is more in line with the actual situation of the mine, and the obtained stability time of the roof is more accurate, which provides a more accurate and powerful reference for the management of the goaf and the design of the connection of the working face in the later stage of the mine.

[0079] The above is only the preferred specific implementation of the present application, but the protection scope of the present application is not limited to this, any person skilled in the art can easily think of changes or replacements within the technical range disclosed in the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for determining the stabilization time of the roof in a goaf area of ​​a rockburst mine, characterized in that, Includes the following steps: Obtain the direction and influence range of the bearing stress at different stages of the working face's advancement; Obtain the trajectory and potential range of microseismic activity at different stages of the working face's advancement; Based on the influence range of the support stress and the influence range of the microseismic activity, the influence range of the stress on the direction and tendency of mining at different stages of the working face is obtained. By comprehensively comparing the influence range of the support stress and the influence range of the microseismic activity, the larger value is taken as the basis, and adjustments are made based on the actual geological structure conditions, special geological conditions and mining conditions of the working face to obtain the influence range of the stress on the direction and dip of the working face at different advancement stages. Based on the analysis of the attenuation characteristics of micro-vibration frequency, total energy and mining time within the range of influence of mining-induced stress, the stabilization time of the low-level roof in the goaf is obtained. The process of obtaining the stabilization time of the low-level roof in the goaf includes: obtaining microseismic activity within the corresponding mining-induced stress influence range after the completion of mining at different stages of the working face; statistically analyzing the microseismic activity and classifying the frequency and total energy of the microseismic activity into different attenuation levels; calculating the time required for the microseismic activity within the corresponding mining-induced stress influence range to attenuate to a predetermined stability level after the completion of mining at different stages of the working face, and using the cumulative number of days that meet the stability level conditions as the initial stabilization time of the low-level roof in the goaf; determining the low-level roof activity stabilization time coefficient based on the working face microseismic monitoring conditions and geological mining conditions; and obtaining the final stabilization time of the low-level roof in the goaf based on the initial stabilization time of the low-level roof in the goaf and the low-level roof activity stabilization time coefficient. Based on the analysis of the influence range of the mining-induced stress, the decay characteristics of the surface subsidence rate and the mining time are obtained to determine the stabilization time of the high-level roof in the goaf. The process of obtaining the stabilization time of the high-level roof in the goaf includes: obtaining the surface subsidence values ​​within the corresponding mining-induced stress influence range after the completion of mining at different stages of the working face; statistically analyzing the surface subsidence values ​​and classifying the surface subsidence rate into different attenuation levels; calculating the time required for the surface subsidence rate within the corresponding mining-induced stress influence range to decay to a predetermined stability level after the completion of mining at different stages of the working face, and using the cumulative number of days that meet the stability level conditions as the initial stabilization time of the high-level roof in the goaf; determining the high-level roof activity stabilization time coefficient based on the surface subsidence monitoring conditions and geological mining conditions of the working face; and obtaining the final stabilization time of the high-level roof in the goaf based on the initial stabilization time of the high-level roof in the goaf and the high-level roof activity stabilization time coefficient. By comprehensively comparing the stabilization time of the low-level roof of the goaf with the stabilization time of the high-level roof of the goaf, the maximum value is taken as the stabilization time of the roof of the goaf.

2. The method for determining the stabilization time of the roof in the goaf of a rockburst mine according to claim 1, characterized in that, The process of obtaining the influence range of the support stress includes: obtaining the comprehensive columnar section of the working face and the physical and mechanical parameters of the coal and rock mass; constructing a three-dimensional numerical model; excavating the three-dimensional numerical model according to the actual mining speed of the working face; extracting the support stress data in front of and laterally at the advancing position of the working face; the distance between the advancing position and the position where the support stress decreases to the original stress position of the coal seam is the initial influence range of the support stress of the working face strike and dip; setting the influence coefficient of the support stress influence range based on the actual geological structure conditions of the working face, special geological conditions and mining conditions; and obtaining the final influence range of the support stress based on the initial influence range of the support stress and the influence coefficient of the support stress influence range.

3. The method for determining the stabilization time of the roof in the goaf of a rockburst mine according to claim 1, characterized in that, The process of obtaining the influence range of the microseismic activity includes: acquiring microseismic data during the longwall mining process, processing and analyzing the microseismic data to obtain microseismic location maps for different mining stages, and based on the microseismic location maps, determining a range greater than or equal to 10. 3 J microseismic events or more than 3 events with a magnitude of less than 10 3 The distance from the microseismic event cluster area to the working face advance position is the initial microseismic activity influence range. Based on the layout of microseismic stations at the working face, and special geological and mining conditions, the influence coefficient of the microseismic activity influence range is set. The final microseismic activity influence range is obtained based on the initial microseismic activity influence range and the influence coefficient of the microseismic activity influence range.

4. The method for determining the stabilization time of the roof in the goaf of a rockburst mine according to claim 1, characterized in that, The process of obtaining the stabilization time of the low-level roof in the goaf includes: obtaining microseismic activity within the corresponding mining stress influence range after the completion of mining at different stages of the working face; statistically analyzing the microseismic activity; classifying the frequency and total energy of the microseismic activity into different levels; statistically analyzing the time required for the microseismic activity within the corresponding mining stress influence range to reach the corresponding level after the completion of mining at different stages of the working face; considering the low-level roof in the goaf to be basically stable when the microseismic frequency decreases to 5 times / day and the total energy decreases to below 3.0KJ; the total number of days of basic stability is the initial stabilization time of the low-level roof in the goaf; setting a low-level roof activity stabilization time coefficient based on the layout of the microseismic stations in the working face, special geological conditions, and mining conditions; and obtaining the final stabilization time of the low-level roof in the goaf based on the initial stabilization time of the low-level roof in the goaf and the low-level roof activity stabilization time coefficient.

5. The method for determining the stabilization time of the roof in the goaf of a rockburst mine according to claim 1, characterized in that, The process of obtaining the stabilization time of the high-level roof in the goaf includes: obtaining the surface subsidence value within the corresponding mining stress influence range after the completion of mining at different stages of the working face; statistically analyzing the surface subsidence value; classifying the surface subsidence rate into different levels; statistically analyzing the time required for the surface subsidence rate within the corresponding mining stress influence range to reach the corresponding level after the completion of mining at different stages of the working face; considering that the high-level roof in the goaf has reached basic stability when the surface subsidence rate decreases to below 1.0 mm / day; the total number of days accumulated for basic stability is the initial stabilization time of the high-level roof in the goaf after the completion of mining at the working face; setting a high-level roof activity stabilization time coefficient based on the layout of surface subsidence monitoring stations at the working face and special geological and mining conditions; and obtaining the final stabilization time of the high-level roof in the goaf based on the initial stabilization time of the high-level roof in the goaf and the high-level roof activity stabilization time coefficient.

6. The method for determining the stabilization time of the roof in the goaf of a rockburst mine according to claim 3, characterized in that, The analysis of microseismic data is conducted in five-day intervals.

7. The method for determining the stabilization time of the roof in the goaf of a rockburst mine according to claim 4, characterized in that, The statistical analysis of microseismic activity is conducted in 5-day intervals.

8. The method for determining the stabilization time of the roof in the goaf of a rockburst mine according to claim 5, characterized in that, The surface subsidence values ​​were statistically analyzed in 15-30 day intervals.

Images