Rock burst tendency early warning method for working face with free space

Abstract

The application discloses a rock burst advanced tendency early warning method for an open working face, and is specifically implemented according to the following steps: step 1, determining a warning threshold and selecting a working face sample; step 2, determining a warning threshold sample area, a yellow warning line and a red warning line for the selected working face sample; step 3, determining a dynamic period increment of an advanced area of the working face; step 4, determining a static fixed increment coefficient of the advanced area of the working face; step 5, estimating a microseismic event cumulative energy curve of the advanced area under different mining speeds in the next stage of the working face according to steps 2-4; and step 6, determining whether to take early warning treatment according to the microseismic event cumulative energy curve of step 5. The working face advanced tendency early warning method can be used for targeted analysis of a rock burst risk key area of the working face, estimation of a rock burst risk degree of the working face in the next stage, and has great significance for guiding the working face to take treatment measures in advance and to take a reasonable mining speed, and is favorable for safe and efficient production of the working face.

Description

Technical Field

[0001] This invention belongs to the field of coal mine dynamic disaster monitoring and early warning technology, and relates to a method for early warning of the advanced trend of rockburst in the face of an open working face. Background Technology

[0002] In recent years, with the continuous increase in mining depth, the stress level of the coal and rock mass where mining activities take place has also been increasing, and the geological conditions have become increasingly complex. The original level of exploration can no longer meet the geological requirements of high-intensity mining, and rockbursts have gradually become one of the main hazards restricting the efficient production of medium and deep mines. Studies have shown that rockbursts are highly concealed and random, and many rockburst early warning systems fail to collect abnormal precursor information before rockburst accidents occur. Therefore, the key to rockburst prevention and control lies in timely and effective monitoring and identification of rockburst hazard areas and the development trend of hazard states, targeted artificial intervention in the rockburst incubation process of hazard areas, releasing the energy accumulated in the coal and rock mass in advance, blocking the force source of the impact, and thus preventing the occurrence of rockbursts.

[0003] Currently, rockburst-prone mines have established a combined regional and local rockburst hazard monitoring system. Regional monitoring covers the mining area and uses methods such as microseismic monitoring for dynamic load monitoring, while local monitoring covers the rockburst hazard zone and uses methods such as drill cuttings analysis, stress monitoring, and electromagnetic radiation analysis for static load monitoring. Microseismic monitoring can effectively monitor the fracturing and breaking process of the overburden at the working face, and can determine the time, location, and intensity of microseismic events in real time, providing the possibility for analyzing the spatial structure failure and patterns of the overburden at the working face. During actual mining operations, monitoring and early warning mainly rely on absolute and relative values ​​from microseismic monitoring data. However, the accuracy of these warnings is not high, and the predictions have a significant lag, failing to directly predict the rockburst risk of the next stage of the working face. This invention comprehensively considers geological and mining technology factors, combined with the spatiotemporal effects of microseismic monitoring, and proposes an advanced trend early warning method for rockburst-prone working faces, which is of great significance for guiding the safe and efficient production of rockburst-prone working faces. Summary of the Invention

[0004] The purpose of this invention is to provide a method for early warning of the advance trend of rockburst in the face of an open working face, which solves the problems of low accuracy and untimely prediction information in the existing early warning methods.

[0005] The technical solution adopted in this invention is a method for early warning of the advanced trend of rockburst at the working face, which is implemented according to the following steps:

[0006] Step 1: Determine the early warning threshold and select a working surface sample;

[0007] Step 2: For the selected working face sample, determine the early warning threshold sample area, the yellow early warning line, and the red early warning line;

[0008] Step 3: Determine the dynamic periodic increment of the working face's advanced area;

[0009] Step 4: Determine the static fixed increment coefficient of the advanced area of ​​the working face;

[0010] Step 5: Based on Steps 2-4, estimate the cumulative energy curve of microseismic events in the advance area under different mining speeds in the next stage of the working face;

[0011] Step 6: Determine whether to take early warning measures based on the cumulative energy curve of the microseismic event in Step 5.

[0012] The invention is further characterized by:

[0013] Step 1 specifically involves collecting historical impact events in the mine, determining the early warning threshold, and selecting working face samples. If there are no impact events in this mine, impact events in nearby similar mines can be used as a reference.

[0014] Step 2 is implemented in the following steps:

[0015] Step 2.1: Establish the plane coordinates of microseismic events: Take the intersection of the working face and the cut-off point of the goaf roadway as the origin 0, take the mining direction of the working face as the X-axis direction, and take the direction of the goaf roadway toward the solid coal roadway as the Y-axis direction to establish the plane coordinates of microseismic events.

[0016] Step 2.2: In the working surface sample selected in Step 1, project the historical microseismic events along the X-axis onto the Y-axis, using S... Y The Y-axis was divided into intervals, and the cumulative distribution of microseismic energy within each interval was analyzed to determine the key study area A along the Y-axis direction under the influence of the goaf on the working face. Y [Y1, Y2], where S Y The Y-axis segmentation spacing is an integer such as 5m, 10m, 20m, etc., A Y This is the key research area along the Y-axis.

[0017] Step 2.3: Focus on research area A Y Microseismic events within (Y1, Y2) are projected along the Y-axis onto the X-axis, with S... X The X-axis was divided into intervals to analyze the cumulative distribution of microseismic energy within each interval, forming a key study area A along the X-axis. X The cumulative energy curve of historical microseismic events within (X1, X2) is C0, where S X The interval for division along the X-axis is an integer such as 5m, 10m, 20m, etc. X This is the key research area along the X-axis.

[0018] Step 2.4: Identify the area A where the impact event occurred. XYThis refers to the warning threshold sample area AT, which is located along the X-axis at point A. X (X1, X2], located at A along the Y-axis direction Y [Y1, Y2], where A XY AT represents the area where the impact event is manifested, and AT represents the sample area for the early warning threshold.

[0019] Step 2.5: Analyze the cumulative energy E of microseismic events within the early warning threshold sample area AT. AT E respectively AT1 E AT2 , ..., E ATn , of which E AT Accumulate energy for microseismic events;

[0020] Step 2.6, MIN(E) AT1 E AT2 , ..., E ATn ) is used as a yellow warning line for early trend warning, and AVE(E) is used as a warning line for early trend warning. AT1 E AT2 , ..., E ATn (This serves as a red warning line for early trend forecasting.)

[0021] Step 3 is implemented in the following steps:

[0022] Step 3.1: Using the cumulative energy E of microseismic events within the early warning threshold sample area AT from Step 2.5... AT Based on this, similar impact events are selected as the basis for the periodic increment of the advanced area according to the current conditions of the working face.

[0023] Step 3.2: The area on both sides of the extended impact manifestation event early warning threshold sample area AT is the sensitivity analysis area SA. The current mining speed is denoted as V0. The fixed area method is used to macroscopically analyze the cumulative energy increment ΔE of microseismic events within this fixed area at different periods. DF ;

[0024] Step 3.3: By comparing the cumulative energy increment ΔE of microseismic events DF Analysis of the cumulative energy increment ΔE of microseisms within the AT region of the early warning threshold sample area. DF Compared to the sensitivity of surrounding areas, the optimal early warning period (BWP) was selected.

[0025] Step 3.4: Using the fixed working face method, analyze the microseismic events within the warning threshold sample area AT in the leading region ΔX of the working face. n Cumulative energy increment ΔE of internal microseismic events n , where △X n The working face leading region (△X1, △X2, ..., △X) n ), △E nThe cumulative energy increment of microseismic events (ΔE1, ΔE2, ..., ΔE) n );

[0026] Step 3.5: Statistically analyze the microseismic events at the working face, macroscopically analyze the proportional coefficient λ1 of microseismic increments between different mining speeds, and extrapolate the dynamic periodic increment of the advanced area of ​​the working face under different mining speeds as λ1(ΔE1, ΔE2, ..., ΔE...). n ).

[0027] Step 4 specifically involves: screening influencing factors F based on the geological occurrence and mining technology conditions of the working face. i Analyzing the static impact λ through historical data Fi Identify the advanced area △X of the working face in step 3.4. n Internal static fixed increment coefficient λ2=Πλ Fi , where λ Fi λ is the static influence parameter, and λ2 is the static fixed increment coefficient.

[0028] Step 5 specifically involves: recording the cumulative energy curve C0 of microseismic events since the start of mining operations at the current working face. * The superimposed dynamic periodic increment and static fixed increment coefficient of the advanced area of ​​the working face are ΔE = λ1λ2(ΔE1, ΔE2, ..., ΔE2). n ), predicting the cumulative energy curve of microseismic activity in the advance area under different mining rates in the next stage of the working face C i =C0 * +△E, where i represents the pushing speed, i = 1, 2, ..., n; C i This represents the cumulative energy curve of microseismic events in the leading region, C0. * The curve represents the cumulative energy of a microseismic event, and ΔE represents the cumulative energy increment curve of the microseismic event.

[0029] Step 6 is implemented in the following steps:

[0030] Step 6.1, if the cumulative energy curve of the microseismic event is C0 * If the area exceeds the warning line, no advanced trend forecast will be made, and a warning will be issued directly.

[0031] If the cumulative energy curve of the microseismic event is C0 * If the warning line area is not exceeded, then based on the current mining speed i, estimate the cumulative energy curve C of microseismic events in the advanced area under the condition of uniform or accelerated mining speed in the next cycle. i C i+1 C i+2 ...;

[0032] If the cumulative energy curve of the microseismic event is C iIf there are areas exceeding the warning line, then warning measures will be taken based on the mining speed i.

[0033] If the cumulative energy curve of the microseismic event is C i There are no areas exceeding the warning line, but the cumulative energy curve C of the microseismic events... i+1 If there are areas exceeding the warning line, it is recommended that the mining speed of the working face not exceed i (uniform mining speed) and that monitoring intensity be increased.

[0034] If the cumulative energy curve of the microseismic event is C i+1 There are no areas exceeding the warning line, but the cumulative energy curve C of the microseismic events... i+2 If there are areas exceeding the warning line, it is recommended that the mining speed of the working face not exceed i+1 constant speed mining, and the monitoring intensity be strengthened, and so on;

[0035] Step 6.2: If the cumulative energy of microseismic events in the advanced area of ​​the working face exceeds the red warning line, the working face shall be stopped immediately. Professional technicians shall conduct a comprehensive analysis. After all risk points in the advanced area of ​​the working face have been investigated and eliminated, the mining speed shall be reduced by 1 to 2 cuts and the operation shall continue. If the cumulative energy of microseismic events in the advanced area of ​​the working face exceeds the yellow warning line, after all risk points in the advanced area of ​​the working face have been investigated and eliminated, the mining speed shall not exceed the current mining speed and the operation shall continue. At the same time, the monitoring intensity shall be strengthened.

[0036] The beneficial effects of this invention are:

[0037] This invention provides an early warning method for the trend of rockburst in working faces. It can specifically analyze key areas of rockburst risk in working faces, especially key areas of rockburst danger during the mining period of working faces affected by goaf, and predict the degree of rockburst risk in the next stage of working faces. It is of great significance for guiding working faces to take disposal measures in advance and adopt reasonable mining speed, which is conducive to safe and efficient production of working faces. Attached Figure Description

[0038] Figure 1 This is a flowchart of the method for early warning of the advance trend of rockburst at the working face according to the present invention;

[0039] Figure 2 This is a schematic diagram of the geodetic coordinate distribution of microseismic events in the 31103 working face of the present invention;

[0040] Figure 3 This is a schematic diagram of the relative coordinate distribution of microseismic events in the 31103 working face of the present invention;

[0041] Figure 4 This is a schematic diagram of the distribution of historical microseismic events along the Y-axis at the 31103 working face of the present invention;

[0042] Figure 5This is the cumulative energy curve C0 of historical microseismic events at the 31103 working face of the present invention;

[0043] Figure 6 The cumulative energy increment and early warning E of microseismic activity at the 31104 working face of this invention. 黄 Ratio diagram;

[0044] Figure 7 This is the advanced trend warning curve for the 31104 working face of this invention on September 22nd;

[0045] Figure 8 This is a schematic diagram showing the regression of the actual cumulative energy and the estimated cumulative energy of the 31104 working face of the present invention. Detailed Implementation

[0046] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0047] Example 1

[0048] This invention provides an early warning method for the advanced trend of rockburst at the working face, such as... Figure 1 As shown, please follow these steps:

[0049] Step 1: Determine the early warning threshold and select a working surface sample;

[0050] Step 2: For the selected working face sample, determine the early warning threshold sample area, the yellow early warning line, and the red early warning line;

[0051] Step 3: Determine the dynamic periodic increment of the working face's advanced area;

[0052] Step 4: Determine the static fixed increment coefficient of the advanced area of ​​the working face;

[0053] Step 5: Based on Steps 2-4, estimate the cumulative energy curve of microseismic events in the advance area under different mining speeds in the next stage of the working face;

[0054] Step 6: Determine whether to take early warning measures based on the cumulative energy curve of the microseismic event in Step 5.

[0055] Example 2

[0056] This invention provides an early warning method for the advanced trend of rockburst at the working face, such as... Figure 1 As shown, please follow these steps:

[0057] Step 1: Determine the early warning threshold and select a working surface sample;

[0058] Step 1 specifically involves collecting historical impact events in the mine, determining the early warning threshold, and selecting working face samples. If there are no impact events in this mine, impact events in nearby similar mines can be used as a reference.

[0059] Step 2: For the selected working face sample, determine the early warning threshold sample area, the yellow early warning line, and the red early warning line;

[0060] Step 2 is implemented in the following steps:

[0061] Step 2.1: Establish the plane coordinates of microseismic events: Take the intersection of the working face and the cut-off point of the goaf roadway as the origin 0, take the mining direction of the working face as the X-axis direction, and take the direction of the goaf roadway toward the solid coal roadway as the Y-axis direction to establish the plane coordinates of microseismic events.

[0062] Step 2.2: In the working surface sample selected in Step 1, project the historical microseismic events along the X-axis onto the Y-axis, using S... Y The Y-axis was divided into intervals, and the cumulative distribution of microseismic energy within each interval was analyzed to determine the key study area A along the Y-axis direction under the influence of the goaf on the working face. Y [Y1, Y2], where S Y The Y-axis segmentation spacing is an integer such as 5m, 10m, 20m, etc., A Y This is the key research area along the Y-axis.

[0063] Step 2.3: Focus on research area A Y Microseismic events within (Y1, Y2) are projected along the Y-axis onto the X-axis, with S... X The X-axis was divided into intervals to analyze the cumulative distribution of microseismic energy within each interval, forming a key study area A along the X-axis. X The cumulative energy curve of historical microseismic events within (X1, X2) is C0, where S X The interval for division along the X-axis is an integer such as 5m, 10m, 20m, etc. X This is the key research area along the X-axis.

[0064] Step 2.4: Identify the area A where the impact event occurred. XY This refers to the warning threshold sample area AT, which is located along the X-axis at point A. X (X1, X2], located at A along the Y-axis direction Y [Y1, Y2], where A XY AT represents the area where the impact event is manifested, and AT represents the sample area for the early warning threshold.

[0065] Step 2.5: Analyze the cumulative energy E of microseismic events within the early warning threshold sample area AT. AT E respectively AT1 E AT2 , ..., E ATn , of which E AT Accumulate energy for microseismic events;

[0066] Step 2.6, MIN(E) AT1 E AT2 , ..., E ATn ) is used as a yellow warning line for early trend warning, and AVE(E) is used as a warning line for early trend warning. AT1 E AT2 , ..., E ATn (This serves as a red warning line for early trend forecasting;)

[0067] Step 3: Determine the dynamic periodic increment of the working face's advanced area;

[0068] Step 3 is implemented in the following steps:

[0069] Step 3.1: Using the cumulative energy E of microseismic events within the early warning threshold sample area AT from Step 2.5... AT Based on this, similar impact events are selected as the basis for the periodic increment of the advanced area according to the current conditions of the working face.

[0070] Step 3.2: The area on both sides of the extended impact manifestation event early warning threshold sample area AT is the sensitivity analysis area SA. The current mining speed is denoted as V0. The fixed area method is used to macroscopically analyze the cumulative energy increment ΔE of microseismic events within this fixed area at different periods. DF ;

[0071] Step 3.3: By comparing the cumulative energy increment ΔE of microseismic events DF Analysis of the cumulative energy increment ΔE of microseisms within the AT region of the early warning threshold sample area. DF Compared to the sensitivity of surrounding areas, the optimal early warning period (BWP) was selected.

[0072] Step 3.4: Using the fixed working face method, analyze the microseismic events within the AT area of ​​the early warning threshold sample region as they precede the working face by ΔX. n Cumulative energy increment of microseisms in the region ΔE n , where △X n The working face leading region (△X1, △X2, ..., △X) n ), △E n The cumulative energy increment of microseismic events (ΔE1, ΔE2, ..., ΔE) n );

[0073] Step 3.5: Statistically analyze the microseismic events at the working face, macroscopically analyze the proportional coefficient λ1 of microseismic increments between different mining speeds, and extrapolate the dynamic periodic increment λ1 (ΔE1, ΔE2, ..., ΔE) of the advanced area of ​​the working face under different mining speeds. n );

[0074] Step 4: Determine the static fixed increment coefficient of the advanced area of ​​the working face;

[0075] Step 4 specifically involves: screening influencing factors F based on the geological occurrence and mining technology conditions of the working face. i Analyzing the static impact λ through historical data Fi In step 3.4, the working surface is ahead (△X1, △X2, ..., △X). n The static fixed increment coefficient λ2 = Πλ within the region Fi , where λ Fi λ is the static influence parameter, and λ2 is the static fixed increment coefficient.

[0076] Step 5: Based on Steps 2-4, estimate the cumulative energy curve of microseismic events in the advance area under different mining speeds in the next stage of the working face;

[0077] Step 5 specifically involves: recording the cumulative energy curve C0 of microseismic events since the start of mining operations at the current working face. * The superimposed dynamic periodic increment and static fixed increment coefficient of the advanced area of ​​the working face are ΔE = λ1λ2(ΔE1, ΔE2, ..., ΔE2). n ), predicting the cumulative energy curve of microseismic activity in the advance area under different mining rates in the next stage of the working face C i =C0 * +△E, where i represents the pushing speed, i = 1, 2, ..., n; C i This represents the cumulative energy curve of microseismic events in the leading region, C0. * The curve represents the cumulative energy of a microseismic event, and ΔE represents the cumulative energy increment curve of the microseismic event.

[0078] Step 6: Determine whether to take early warning measures based on the cumulative energy curve of the microseismic events in Step 5;

[0079] Step 6 is implemented in the following steps:

[0080] Step 6.1, if the cumulative energy curve of the microseismic event is C0 * If the area exceeds the warning line, no advanced trend forecast will be made, and a warning will be issued directly.

[0081] If the cumulative energy curve of the microseismic event is C0 * If the warning line area is not exceeded, then based on the current mining speed i, estimate the cumulative energy curve C of microseismic events in the advanced area under the condition of uniform or accelerated mining speed in the next cycle. i C i+1 C i+2 ...;

[0082] If the cumulative energy curve of the microseismic event is C i If there are areas exceeding the warning line, then warning measures will be taken based on the mining speed i.

[0083] If the cumulative energy curve of the microseismic event is C i There are no areas exceeding the warning line, but the cumulative energy curve C of the microseismic events... i+1 If there are areas exceeding the warning line, it is recommended that the mining speed of the working face not exceed i (uniform mining speed) and that monitoring intensity be increased.

[0084] If the cumulative energy curve of the microseismic event is C i+1 There are no areas exceeding the warning line, but the cumulative energy curve C of the microseismic events... i+2 If there are areas exceeding the warning line, it is recommended that the mining speed of the working face not exceed i+1 constant speed mining, and the monitoring intensity be strengthened, and so on;

[0085] Step 6.2: If the cumulative energy of microseismic events in the advanced area of ​​the working face exceeds the red warning line, the working face shall be stopped immediately. Professional technicians shall conduct a comprehensive analysis. After all risk points in the advanced area of ​​the working face have been investigated and eliminated, the mining speed shall be reduced by 1 to 2 cuts and the operation shall continue. If the cumulative energy of microseismic events in the advanced area of ​​the working face exceeds the yellow warning line, after all risk points in the advanced area of ​​the working face have been investigated and eliminated, the mining speed shall not exceed the current mining speed and the operation shall continue. At the same time, the monitoring intensity shall be strengthened.

[0086] Example 3

[0087] This invention provides an early warning method for the advanced trend of rockburst at the working face, such as... Figure 1 As shown, please follow these steps:

[0088] Step 1: Collect historical impact events in mine 31103. The impact events in this working face are particularly prominent and can be used as a sample working face for early warning threshold selection.

[0089] Step 2: For the selected working face sample, determine the early warning threshold sample area, the yellow early warning line, and the red early warning line;

[0090] Step 2 is implemented in the following steps:

[0091] Step 2.1: Since the 31103 working face is arranged in a northwest-southeast direction, the polar coordinate method is used to convert the plane coordinates of microseismic events within the working face from geodetic coordinates, as shown in Figure 2.1. Figure 2 Adjust to relative coordinates of the working surface, such as Figure 3 ;

[0092] Step 2.2: Project the historical microseismic events of the sample working surface along the X-axis onto the Y-axis, as shown below. Figure 4 As shown, the Y-axis is divided at 5m intervals. The cumulative distribution of microseismic energy in each interval is analyzed to determine the key study area A along the Y-axis under the influence of the goaf on the working face. Y (-60, 60];

[0093] Step 2.3: Focus on research area A Y Microseismic events within the (-60, 60) interval are projected onto the X-axis along the Y-axis. The X-axis is divided at 20m intervals to analyze the cumulative distribution of microseismic energy within each interval. A key study area A is formed along the X-axis. Y The cumulative energy curve C0 of historical microseismic events within (-60, 60] is shown below. Figure 5 As shown;

[0094] Step 2.4: Identify the area A where the impact event occurred. XY Taking the impact manifestation on September 3, 2019 as an example, the working face was pushed to 740.05m, and the manifestation location was 67m ahead of schedule. The early warning threshold sample area AT was located at A along the X-axis. X (800, 820], located at A along the Y-axis direction Y (-60, 60];

[0095] Step 2.5: Analyze the cumulative energy E of microseismic events within the early warning threshold sample area AT. AT E respectively AT1 E AT2 , ..., E ATn ;

[0096] Step 2.6, MIN(E) AT1 E AT2 , ..., E ATn ) is used as a yellow warning line for early trend warning, and AVE(E) is used as a warning line for early trend warning. AT1 E AT2 , ..., E ATn As a red warning line for advanced trend early warning, taking the 31103 working face as an example, historical impact events were statistically analyzed, and 1.6E6J was designated as the yellow warning line E. 黄 ;

[0097] Step 3: Determine the dynamic periodic increment of the working face's advanced area;

[0098] Step 3 is implemented in the following steps:

[0099] Step 3.1: Accumulate the energy E of microseismic events within the sample area AT of the early warning threshold. AT Based on this, the 31104 working face will continue to use the impact event of August 8th as the basis for the incremental increase of the advanced regional cycle on September 22nd;

[0100] Step 3.2: Extend the impact manifestation event early warning threshold sample area AT. The 100m range on both sides is the sensitivity analysis area SA. The current mining speed is recorded as 6 cuts / day. The fixed area method is used to macroscopically analyze the cumulative energy increment ΔE of microseismic events within the fixed area around this range. DF ;

[0101] Step 3.3: By comparing the cumulative energy increment ΔE of microseismic events DF Analysis of the cumulative energy increment ΔE of microseisms within the AT region of the early warning threshold sample area. DF Compared to the sensitivity of surrounding areas, the optimal early warning period (BWP) is selected as 1 week;

[0102] Step 3.4: Using the fixed working face method, analyze the microseismic events leading the working face (ΔX1, ΔX2, ..., ΔX) within the AT area of ​​the early warning threshold sample region. n The cumulative energy increment of microseisms within the range (ΔE1, ΔE2, ..., ΔE) n ),like Figure 6 Accumulated energy increment and early warning E for microseismic events 黄 ratio;

[0103] Step 3.5: Statistically analyze the micro-seismic events at the working face, and macroscopically analyze the micro-seismic increment ratio coefficient λ1 between different mining speeds. At a mining speed of 7 cuts / day, the micro-seismic increment is approximately twice that at a mining speed of 6 cuts / day. When the mining speed is 6 cuts / day, the dynamic periodic increment of the advanced area is (ΔE1, ΔE2, ..., ΔE...). n When the working face advance rate is 7 cuts / day, the dynamic cycle increment of the advance area is 2(△E1, △E2, ..., △E). n );

[0104] Step 4: Determine the static fixed increment coefficient of the advanced area of ​​the working face;

[0105] Step 4 specifically involves: combining the geological occurrence and mining technology conditions of the working face advance area on September 22, mainly affected by the connecting roadway, with a static impact area of ​​30m on both sides of the connecting roadway. Based on historical data analysis, the static impact level is 1.25, and the static fixed increment coefficient within the working face advance range of 40-100m is determined to be 1.25.

[0106] Step 5: Based on Steps 2-4, estimate the cumulative energy curve of microseismic events in the advance area under different mining speeds in the next stage of the working face;

[0107] Step 5 specifically involves: Figure 7 As shown, the blue line on September 22nd represents the cumulative energy curve C0 of microseismic events recorded in real-time at the working face since the start of mining. * The dynamic periodic increment and static fixed increment of the advanced area of ​​the superimposed working face are ΔE = λ1λ2(ΔE1, ΔE2, ..., ΔE). n The gray line is C6, and the yellow line is C7;

[0108] Step 6: Based on the cumulative energy curve of microseismic events in the advanced area of ​​the working face, determine the following: If 6 cutters are used for the advanced advance of the access roadway in the coming week, the maximum daily increase of 100m will be 16%, and it is expected to reach 50% of the warning indicator within the coming week, with a low risk of dynamic manifestation; If 7 cutters are used, the maximum daily increase of 100m will be 32%, and after adding the influence of the No. 8 and No. 9 connecting roadways, it is not expected to reach the warning line, and it is expected to reach 75% of the warning indicator within the coming week. It is expected that the on-site mine pressure manifestation will be slightly lower than the level of the No. 9 connecting roadway, and the risk of dynamic manifestation will increase, but it is relatively controllable.

[0109] Statistics show that from September 22nd to October 9th, the 31104 working face adopted a uniform mining rate of 6 cuts per day. A comparison was made between C6 on September 22nd and C0 on October 9th. * Overlapping areas, such as Figure 8 As shown, the actual cumulative energy and the estimated cumulative energy have good consistency.

[0110] In summary, this invention provides an early warning method for the trend of rockburst in a working face. The embodiments illustrate the early warning effect of this method, which has certain guiding significance for the prevention and control of rockburst in mines.

Claims

1. A method for early warning of the advanced trend of rockburst at the working face, characterized in that, The specific steps are as follows: Step 1: Determine the early warning threshold and select a working surface sample; Step 2: For the selected working face sample, determine the early warning threshold sample area, the yellow early warning line, and the red early warning line; specifically, implement this according to the following steps: Step 2.1: Establish the plane coordinates of microseismic events: Take the intersection of the working face and the cut-off point of the goaf roadway as the origin 0, take the mining direction of the working face as the X-axis direction, and take the direction of the goaf roadway toward the solid coal roadway as the Y-axis direction to establish the plane coordinates of microseismic events. Step 2.2: In the working surface sample selected in Step 1, project the historical microseismic events along the X-axis onto the Y-axis, using S... Y The Y-axis was divided into intervals, and the cumulative distribution of microseismic energy within each interval was analyzed to determine the key study area A along the Y-axis direction under the influence of the goaf on the working face. Y [Y1, Y2], where S Y A represents the segmentation spacing along the Y-axis. Y Indicates the key research area along the Y-axis; Step 2.3: Focus on research area A Y Microseismic events within (Y1, Y2) are projected along the Y-axis onto the X-axis, with S... X The X-axis was divided into intervals to analyze the cumulative distribution of microseismic energy within each interval, forming a key study area A along the X-axis. X The cumulative energy curve of historical microseismic events within (X1, X2] is C0, where S X A represents the segmentation spacing along the X-axis. X Indicates the key research area along the X-axis; Step 2.4: Identify the area A where the impact event occurred. XY This refers to the warning threshold sample area AT, which is located along the X-axis at point A. X (X1, X2], located at A along the Y-axis direction Y [Y1, Y2], where A XY This indicates the area where the impact event is manifested, and AT indicates the sample area for the warning threshold. Step 2.5: Analyze the cumulative energy E of microseismic events within the early warning threshold sample area AT. AT E respectively AT1 E AT2 , ..., E ATn , of which E AT This represents the cumulative energy of a microseismic event; Step 2.6, MIN(E) AT1 E AT2 , ..., E ATn ) is used as a yellow warning line for early trend warning, and AVE(E) is used as a warning line for early trend warning. AT1 E AT2 , ..., E ATn () serves as a red warning line for advanced trend forecasting; Step 3: Determine the dynamic periodic increment of the working face's advanced area; Step 4: Determine the static fixed increment coefficient of the advanced area of ​​the working face; Step 5: Based on Steps 2-4, estimate the cumulative energy curve of microseismic events in the advance area under different mining speeds in the next stage of the working face; Step 6: Determine whether to take early warning measures based on the cumulative energy curve of the microseismic event in Step 5.

2. The method for early warning of the advance trend of rockburst at the working face according to claim 1, characterized in that, Step 1 specifically involves collecting historical impact events in the mine, determining the early warning threshold, and selecting working face samples. If there are no impact events in this mine, impact events in nearby similar mines can be referenced.

3. The method for early warning of the advance trend of rockburst at an open working face according to claim 1, characterized in that, Step 3 is implemented in the following steps: Step 3.1: Using the cumulative energy E of microseismic events within the early warning threshold sample area AT from Step 2.5... AT Based on this, similar impact events are selected as the basis for the periodic increment of the advanced area according to the current conditions of the working face. Step 3.2: The area on both sides of the extended impact manifestation event early warning threshold sample area AT is the sensitivity analysis area SA. The current mining speed is denoted as V0. The fixed area method is used to macroscopically analyze the cumulative energy increment ΔE of microseismic events within this fixed area at different periods. DF ; Step 3.3: By comparing the cumulative energy increment ΔE of microseismic events DF Analysis of the cumulative energy increment ΔE of microseisms within the AT region of the early warning threshold sample area. DF The optimal warning period (BWP) was selected based on the sensitivity of the surrounding area. Step 3.4: Using the fixed working face method, analyze the microseismic events within the warning threshold sample area AT in the leading region ΔX of the working face. n Cumulative energy increment of internal microseismic events ΔE n , where △X n Indicates the advanced region of the working face (△X1, △X2, ..., △X). n ), △E n This represents the cumulative energy increment of microseismic events (ΔE1, ΔE2, ..., ΔE). n ); Step 3.5: Statistically analyze the microseismic events at the working face, macroscopically analyze the microseismic increment ratio coefficient λ1 between different mining speeds, and extrapolate the dynamic periodic increment of the working face's advanced area under different mining speeds as λ1 (ΔE1, ΔE2, ..., ΔE...). n ).

4. The method for early warning of the advance trend of rockburst at the working face according to claim 3, characterized in that, Step 4 specifically involves: screening influencing factors F based on the geological occurrence and mining technology conditions of the working face. i Analyzing the static impact λ through historical data Fi Identify the advanced area △X of the working face in step 3.

4. n Internal static fixed increment coefficient λ2=Πλ Fi , where λ Fi λ represents the static influence parameter, and λ2 represents the static fixed increment coefficient.

5. The method for early warning of the advance trend of rockburst at the working face according to claim 4, characterized in that, Step 5 specifically involves: based on the real-time recording of the cumulative energy curve C0 of microseismic events since the start of mining at the current working face. The dynamic periodic increment and static fixed increment coefficient of the advanced area of ​​the superimposed working face are ΔE=λ1λ2 (ΔE1, ΔE2, ..., ΔE2). n ), predicting the cumulative energy curve of microseismic activity in the advance area under different mining rates in the next stage of the working face C i =C0 +△E, where i represents the pushing speed, i=1, 2, ..., n; C i This represents the cumulative energy curve of microseismic events in the leading region, C0. The curve represents the cumulative energy of a microseismic event, and ΔE represents the cumulative energy increment curve of the microseismic event.

6. The method for early warning of the advance trend of rockburst at an open working face according to claim 5, characterized in that, Step 6 is implemented in the following steps: Step 6.1, if the cumulative energy curve of the microseismic event is C0 If the area exceeds the warning line, no advanced trend forecast will be made, and a warning will be issued directly. If the cumulative energy curve of the microseismic event is C0 If the warning line area is not exceeded, then based on the current mining speed i, estimate the cumulative energy curve C of microseismic events in the advanced area under the condition of uniform or accelerated mining speed in the next cycle. i C i+1 C i+2 ...; If the cumulative energy curve of the microseismic event is C i If there are areas exceeding the warning line, then warning measures will be taken based on the mining speed i. If the cumulative energy curve of the microseismic event is C i There are no areas exceeding the warning line, but the cumulative energy curve C of the microseismic events... i+1 If there are areas exceeding the warning line, it is recommended that the mining speed of the working face not exceed i (uniform mining speed) and that monitoring intensity be increased. If the cumulative energy curve of the microseismic event is C i+1 There are no areas exceeding the warning line, but the cumulative energy curve C of the microseismic events... i+2 If there are areas exceeding the warning line, it is recommended that the mining speed of the working face not exceed i+1 constant speed mining, and the monitoring intensity be strengthened, and so on; Step 6.2: If the cumulative energy of microseismic events in the advanced area of ​​the working face exceeds the red warning line, the working face shall be stopped immediately. Professional technicians shall conduct a comprehensive analysis. After all risk points in the advanced area of ​​the working face have been investigated and eliminated, the mining speed shall be reduced by 1-2 cuts and the operation shall continue. If the cumulative energy of microseismic events in the advanced area of ​​the working face exceeds the yellow warning line, after all risk points in the advanced area of ​​the working face have been investigated and eliminated, the mining speed shall not exceed the current mining speed and the operation shall continue. At the same time, the monitoring intensity shall be strengthened.

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