Early warning method for impact danger in adjacent gob roadway tunneling period based on trend regression analysis

Abstract

The invention discloses a trend regression analysis-based impact danger early warning method during adjacent gob roadway tunneling, which specifically comprises the following steps of: arranging a stress meter during the stoping period of a working face adjacent to a target roadway to monitor the stress of a coal seam, and drawing a regional basic stress curve; all micro-seismic events of the working face are collected during stoping of the working face adjacent to the target roadway, a target area is delimited, grids are divided in the target area, and a micro-seismic event total energy distribution curve is drawn according to the micro-seismic events in the target area; according to the micro-seismic event total energy distribution curve and the regional basic stress curve, a rock burst risk prediction curve is obtained; according to data of rock burst or large energy events of a mine, comprehensive early warning indexes of dangerous areas of different grades are divided, and advanced treatment is carried out on the dangerous areas; during roadway tunneling, dynamically monitoring and drawing an impact risk prediction curve, and performing on-site zoning pressure relief; according to the method, the early warning accuracy is high, and the safety of the adjacent gob roadway in the tunneling period is greatly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of coal mine dynamic disaster prevention and control, and specifically relates to an impact hazard early warning method during tunneling of adjacent empty tunnels based on trend regression analysis. Background Art The prediction and early warning of rock burst disasters in coal mines is a global problem. Traditional rock burst early warning methods are mainly mechanism-driven, that is, by deeply exploring the precursor information of rock burst, such as microseismic, stress, electromagnetic radiation of coal and rock, and summarizing the mutation law of precursor information based on a large number of rock burst accident cases, the occurrence of rock burst can be predicted in advance. After more than ten years of development and application, the mechanism-driven precursor information early warning method has gradually shown certain limitations. First, the geological conditions and mining methods of different mines are different, and even the rock burst mechanism of different working faces in the same mine is different. The use of the same precursor information early warning method under different working conditions will essentially lead to a decrease in the accuracy of early warning; second, improving the accuracy of early warning often requires sufficient early warning cases to support it. For mines with fewer rock burst accidents, the sample data is small, and it is impossible to accumulate enough precursor warning information. It can only refer to the early warning indicators of surrounding or even other mining areas, which further reduces the accuracy of early warning; third, the traditional precursor information identification and early warning method has a high temporal warning efficiency, but a poor spatial warning efficiency, and it is often difficult to effectively predict the occurrence area of ​​rock burst.

[0002] Tunnels adjacent to empty tunnels are high-incidence areas of rock burst. It is difficult to accurately warn of rock burst during excavation of tunnels adjacent to empty tunnels using traditional rock burst warning methods. Summary of the invention

[0003] The purpose of the present invention is to provide a method for early warning of impact danger during tunneling in adjacent empty tunnels based on trend regression analysis, so as to solve the problem that the existing method has low accuracy in early warning of impact ground pressure during tunneling in adjacent empty tunnels. The technical solution adopted by the present invention is a method for early warning of impact danger during tunneling of adjacent empty tunnels based on trend regression analysis, which is specifically implemented in the following steps: Step 1: During the mining period of the working face adjacent to the target tunnel, stress gauges are deployed to monitor the stress of the coal seam and draw a regional basic stress curve; Step 2, during the mining period of the working face adjacent to the target roadway, all microseismic events of the working face are collected, the target area is delineated, and a grid is divided in the target area, and a total energy distribution curve of the microseismic events is drawn according to the microseismic events in the target area; Step 3, obtaining a rock burst hazard prediction curve based on the total energy distribution curve of microseismic events and the regional foundation stress curve; Step 4: Based on the data of rock burst or high energy events in the mine, the comprehensive early warning indicators of dangerous areas of different levels are divided to carry out advanced treatment of dangerous areas; Step 5: During tunnel excavation, dynamically monitor and draw impact hazard prediction curves, and perform on-site zone pressure relief. The present invention is also characterized in that: The specific process of step 1 is: Step 1.1, determine the target roadway to be warned, before the working face adjacent to the target roadway is affected by mining, take the mining working face as the starting position and set n groups of coal body stress gauges at equal intervals along the working face, and the sensitive components of the n groups of coal body stress gauges penetrate into the stress concentration area of ​​the coal wall; Each group of coal body stress gauges has two, one for shallow stress measurement and one for deep stress measurement. The distance between the two coal body stress gauges in each group is ≤2m. The coal body stress gauges for measuring deep stress are numbered 1, 2, 3, ..., n along the working face direction, and the coal body stress gauges for measuring shallow stress are numbered 1, 2, 3, ..., n. ’ , 2 ’ , 3 ’ ,…,n ’ ; Step 1.2, during the mining period of the working face, continuously collect monitoring data of the media stress gauges, and when the working face is mined close to the first group of coal body stress gauges, remove the first group of coal body stress gauges and install them behind the last group of media stress gauges with the spacing remaining unchanged; Step 1.3, extract the maximum stress values ​​measured by the coal body stress gauge for measuring deep stress and the coal body stress gauge for measuring shallow stress from the initial installation to the removal, and record the maximum deep stress value as , the maximum value of shallow stress is recorded as , read the distance between each coal body stress gauge measuring deep stress and the advance working face , read the distance between each coal body stress gauge measuring shallow stress and the advance working face ; Step 1.4, calculate the average value of the maximum stress and distance average , the expression is as follows: (1) (2); Step 1.5, is the horizontal axis, As the vertical axis, draw the regional foundation stress curve.

[0004] In step 1.1, the depth of shallow stress measurement is ≥1.5h, and the depth of shallow stress measurement is ≥3h, where h is the mining height of the coal seam. The distance between two adjacent groups of coal stress gauges is ≤30m, and the number of groups of coal stress gauges is ≥10.

[0005] The specific process of step 2 is: Step 2.1, during the mining period of the working face adjacent to the target roadway, all microseismic events of the working face are collected and saved in the format of time, coordinates, and event energy; Step 2.2, taking the distance between the cut hole and the stop mining line of the working face adjacent to the target roadway as the length L, taking the range of the left and right sides S of the wall of the mining roadway close to the adjacent working face as the width, enveloping and drawing a rectangular target area, the mining roadway is located between the target roadway and the working face adjacent to the target roadway; Step 2.3: Taking the cut eye of the working face as the starting point, divide the grids along the working face with a spacing of D, and count the total energy of microseismic events falling in each grid interval. ; The number of grids N and the spacing D satisfy: (3); Step 2.4, is the horizontal axis, The vertical coordinate is used to draw the total energy distribution curve of microseismic events along the direction of the working face.

[0006] The specific process of step 3 is: Step 3.1: Count the total energy of all microseismic events within the rectangular target area. , and the mathematical expectation of the total energy of microseismic events in each grid interval is calculated according to formula (4): ; (4) Step 3.2: Align the regional basic stress curve drawn in step 1 with the horizontal axis of the total energy distribution curve of the microseismic event drawn in step 2, and read the stress value corresponding to each statistical point in the total energy distribution curve of the microseismic event respectively. ; Step 3.3: Calculate the warning stress value at each statistical point in the total energy distribution curve of the microseismic event , the expression is: (5) Step 3.4, is the horizontal axis, With 20° as the vertical coordinate, a comprehensive prediction curve A for rock burst danger in different areas during tunneling in adjacent empty tunnels is drawn.

[0007] The specific process of step 4 is: Step 4.1, collect all data of the working face where rock burst or high energy event occurs in the mine where the target tunnel is located; Step 4.2: Select a characteristic case event and read the maximum stress value of the event area within one day before and after the characteristic case event. Taking the area where the event occurred as the center point, count the microseismic events within the range of S distances to the left and back of the working face and D / 2 distances before and after the working face, and calculate the total energy of the microseismic events ; Step 4.3: Calculate the warning stress value according to formula (6): ; (6) Step 4.4, It is an early warning indicator for the weak impact danger area. It is an early warning indicator for medium impact risk areas. It is an early warning indicator for strong impact risk areas; Step 4.5: For areas predicted to be without impact hazard, excavation shall proceed normally; for areas predicted to be with weak impact hazard or above, decompression and hazard relief measures shall be taken in advance according to the degree of impact hazard.

[0008] In step 4.2, when there is no rock burst accident or a large-energy event that causes obvious damage in the mine, the microseismic event with the highest energy monitored in the mine is taken as the characteristic case event; when there is only one rock burst accident or a large-energy event that causes obvious damage in the mine, this event is taken as the characteristic case event; when there are multiple rock burst accidents or large-energy events that cause obvious damage in the mine, each event is taken as a characteristic case event, and the minimum value of all the warning stress values ​​obtained is used to divide the warning indicators.

[0009] The specific process of step 5 is: Step 5.1, (1) During the excavation of the target tunnel, if the microseismic and stress monitoring system has not yet been deployed, the prediction is based on the comprehensive prediction curve A of rock burst danger in different areas during the excavation of the adjacent empty tunnel obtained in step 3.4; (2) During the excavation of the target tunnel, if only a microseismic monitoring system is deployed, all microseismic events in the target tunnel are collected and saved in the format of time, XYZ coordinates, and event energy; the distance between the target tunnel opening and the stop line is taken as the length L, and the range S on the left and right sides of the wall of the target tunnel close to the adjacent working face is taken as the width. The rectangular target area is enveloping, and the target tunnel opening is taken as the starting point. The grid is divided with a spacing D along the working face direction, and the total energy of the microseismic events falling in each grid interval is counted. , substituted into formula (5), the warning stress value at each statistical point in the total energy distribution curve of the microseismic event is obtained ,by is the horizontal axis, As the vertical coordinate, draw the comprehensive prediction curve B of rock burst danger in different areas during the excavation of adjacent empty tunnels, and make predictions based on the prediction curve B; (3) During the excavation of the target tunnel, if the microseismic monitoring system and coal stress gauges have been arranged according to the process of steps 1.1 to 1.2, repeat steps 1.3 to 1.5 and obtain the basic stress values ​​of each area in the current excavation tunnel. And according to (2), the total energy of microseismic events falling in each grid interval is obtained Substituting into formula (5), we can obtain the warning stress value at each statistical point in the total energy distribution curve of the microseismic event: ,by is the horizontal axis, As the vertical coordinate, the comprehensive prediction curve C of rock burst danger in different areas during the excavation of adjacent empty tunnels is drawn, and the prediction is carried out based on the prediction curve C; Step 5.2, repeat steps 4.1 to 4.4 to obtain early warning indicators for weak, medium and strong impact danger areas. For areas predicted by the prediction curve to be at or above weak impact danger, the drilling cuttings method is used for supplementary monitoring at the side of the roadway; If the amount of diamond powder does not exceed the standard, , the comprehensive prediction curve of impact risk will not be adjusted; If the amount of drilling cuttings exceeds the standard, , the maximum excess multiple, the average excess value, and the difficulty of drilling are used to measure the severity of the drill dust excess. According to each indicator, a stress adjustment coefficient is selected, and three stress adjustment coefficients are obtained. The three stress adjustment coefficients are added together to obtain the adjustment coefficient of the warning stress value at the corresponding measuring point. The stress adjustment coefficient corresponding to each indicator is shown in Table 1: Table 1

[0010] in, The maximum amount of diamond powder measured. is the standard value of diamond powder content, is the maximum drilling depth, The standard hole depth for drilling is It is the sum of the stress adjustment coefficients corresponding to the three indicators item by item; Step 5.3: Adjustment coefficient of the warning stress value at the corresponding measuring point obtained in step 5.2 The warning stress value is adjusted to obtain the adjusted warning stress value, and the comprehensive prediction curve of rock burst danger in different areas during the excavation of adjacent empty tunnels is redrawn according to the adjusted warning stress value as the final prediction curve; Step 5.4: Based on the prediction results, the on-site area is depressurized and treated.

[0011] In step 5.3, the adjusted warning stress value = (1+ ) .

[0012] The beneficial effects of the present invention are: (1) The method for early warning of rock burst danger during tunnel excavation adjacent to empty tunnels based on trend regression analysis is highly applicable and can be applied to mines with different geological conditions, mining methods and rock burst types. It is not highly dependent on early warning cases and can be applied to mines that have experienced one, multiple or no rock burst accidents. (2) The impact hazard warning method during tunneling in adjacent empty tunnels based on trend regression analysis of the present invention can provide advance warning before tunneling and dynamic warning during tunneling for impact risk points in adjacent empty tunnels. The warning accuracy is high, which greatly improves the safety during tunneling in adjacent empty tunnels. (3) The impact hazard warning method during tunneling of adjacent empty tunnels based on trend regression analysis of the present invention can not only warn when there is an impact hazard, but also warn where the impact hazard will occur, which has a stronger guiding significance for the site. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a flow chart of the method of the present invention; Figure 2 is a layout diagram of coal body stress gauges during mining of adjacent working faces in Example 3 of the present invention; Figure 3 is a basic stress curve diagram in Example 3 of the present invention; Figure 4 is a diagram of a method for screening microseismic events during mining of adjacent working faces in Example 3 of the present invention; Figure 5 is a total energy distribution curve diagram of microseismic events in Example 3 of the present invention; Figure 6 is a comprehensive prediction curve diagram of rock burst danger in the target tunnel in Example 3 of the present invention; Figure 7 This is a diagram of a statistical method for total energy of microseismic events at characteristic case events in Example 3 of the present invention; Figure 8 is a comprehensive prediction curve diagram of rock burst danger before excavation in Example 3 of the present invention; Fig. 9 is a diagram of a method for screening microseismic events in a target tunnel in Example 3 of the present invention; Fig.10 It is a comprehensive prediction curve diagram of rock burst danger at 200 m of excavation in Example 3 of the present invention; Fig.11 is a comprehensive prediction curve of rock burst danger at 400 m of excavation in Example 3 of the present invention; Fig.12 It is a comprehensive prediction curve of rock burst danger at 600 m of excavation in Example 3 of the present invention. DETAILED DESCRIPTION

[0013] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0014] Example 1 The impact hazard early warning method during tunneling of adjacent empty tunnels based on trend regression analysis of the present invention is specifically implemented according to the following steps: Step 1: During the mining period of the working face adjacent to the target tunnel, stress gauges are deployed to monitor the stress of the coal seam and draw a regional basic stress curve; Step 2, during the mining period of the working face adjacent to the target roadway, all microseismic events of the working face are collected, the target area is delineated, and a grid is divided in the target area, and a total energy distribution curve of the microseismic events is drawn according to the microseismic events in the target area; Step 3, obtaining a rock burst hazard prediction curve based on the total energy distribution curve of microseismic events and the regional foundation stress curve; Step 4: Based on the data of rock burst or high energy events in the mine, the comprehensive early warning indicators of dangerous areas of different levels are divided to carry out advanced treatment of dangerous areas; Step 5: During tunnel excavation, dynamically monitor and draw impact hazard prediction curves, and perform on-site zone pressure relief.

[0015] Example 2 The present invention provides a method for early warning of impact danger during tunneling in adjacent empty tunnels based on trend regression analysis. Figure 1 As shown, the specific implementation steps are as follows: Step 1: During the mining period of the working face adjacent to the target tunnel, stress gauges are deployed to monitor the stress of the coal seam and draw a regional basic stress curve; The specific process is: Step 1.1, determine the target roadway to be warned, before the working face adjacent to the target roadway is affected by mining, take the mining working face as the starting position and set n groups of coal body stress gauges at equal intervals along the working face, and the sensitive components of the n groups of coal body stress gauges penetrate into the stress concentration area of ​​the coal wall; Each group of coal body stress gauges has two, one for shallow stress measurement and one for deep stress measurement. The distance between the two coal body stress gauges in each group is ≤2m. The coal body stress gauges for measuring deep stress are numbered 1, 2, 3, ..., n along the working face direction, and the coal body stress gauges for measuring shallow stress are numbered 1, 2, 3, ..., n. ’ , 2 ’ , 3 ’ ,…,n ’ ; The depth of shallow stress measurement is ≥1.5h, the depth of shallow stress measurement is ≥3h, where h is the mining height of the coal seam, the distance between two adjacent groups of coal stress gauges is ≤30m, and the number of groups of coal stress gauges is ≥10; Step 1.2, during the mining period of the working face, continuously collect monitoring data of the media stress gauges, and when the working face is mined close to the first group of coal body stress gauges, remove the first group of coal body stress gauges and install them behind the last group of media stress gauges with the spacing remaining unchanged; Step 1.3, extract the maximum stress values ​​measured by the coal body stress gauge for measuring deep stress and the coal body stress gauge for measuring shallow stress from the initial installation to the removal, and record the maximum deep stress value as , the maximum value of shallow stress is recorded as , read the distance between each coal body stress gauge measuring deep stress and the advance working face , read the distance between each coal body stress gauge measuring shallow stress and the advance working face ; Step 1.4, calculate the average value of the maximum stress and distance average , the expression is as follows: (1) (2); Step 1.5, is the horizontal axis, As the ordinate, draw the regional foundation stress curve; Step 2, during the mining period of the working face adjacent to the target roadway, all microseismic events of the working face are collected, the target area is delineated, and a grid is divided in the target area, and a total energy distribution curve of the microseismic events is drawn according to the microseismic events in the target area; The specific process is: Step 2.1, during the mining period of the working face adjacent to the target roadway, all microseismic events of the working face are collected and saved in the format of time, coordinates, and event energy; Step 2.2, taking the distance between the cut hole and the stop mining line of the working face adjacent to the target roadway as the length L, taking the range of the left and right sides S of the wall of the mining roadway close to the adjacent working face as the width, enveloping and drawing a rectangular target area, the mining roadway is located between the target roadway and the working face adjacent to the target roadway; Step 2.3: Taking the cut eye of the working face as the starting point, divide the grids along the working face with a spacing of D, and count the total energy of microseismic events falling in each grid interval. ; The number of grids N and the spacing D satisfy: (3); Step 2.4, is the horizontal axis, As the ordinate, the total energy distribution curve of microseismic events is drawn along the strike of the working face; Step 3, obtaining a rock burst hazard prediction curve based on the total energy distribution curve of microseismic events and the regional foundation stress curve; The specific process is: Step 3.1: Count the total energy of all microseismic events within the rectangular target area. , and the mathematical expectation of the total energy of microseismic events in each grid interval is calculated according to formula (4): ; (4) Step 3.2: Align the regional basic stress curve drawn in step 1 with the horizontal axis of the total energy distribution curve of the microseismic event drawn in step 2, and read the stress value corresponding to each statistical point in the total energy distribution curve of the microseismic event respectively. ; Step 3.3: Calculate the warning stress value at each statistical point in the total energy distribution curve of the microseismic event , the expression is: (5) Step 3.4, is the horizontal axis, As the vertical coordinate, the comprehensive prediction curve A of rock burst danger in different areas during the excavation of adjacent empty tunnels is drawn; Step 4: Based on the data of rock burst or high energy events in the mine, the comprehensive early warning indicators of dangerous areas of different levels are divided to carry out advanced treatment of dangerous areas; The specific process is: Step 4.1, collect all data of the working face where rock burst or high energy event occurs in the mine where the target tunnel is located; Step 4.2: Select a characteristic case event and read the maximum stress value of the event area within one day before and after the characteristic case event. Taking the area where the event occurred as the center point, count the microseismic events within the range of S distances to the left and back of the working face and D / 2 distances before and after the working face, and calculate the total energy of the microseismic events ; When there is no rock burst accident or a large-energy event that causes obvious damage in the mine, the microseismic event with the highest energy monitored in the mine is taken as the characteristic case event; when there is only one rock burst accident or a large-energy event that causes obvious damage in the mine, this event is taken as the characteristic case event; when there are multiple rock burst accidents or large-energy events that cause obvious damage in the mine, each event needs to be taken as a characteristic case event, and the minimum value of all the warning stress values ​​obtained is used to divide the warning indicators; Step 4.3: Calculate the warning stress value according to formula (6): ; (6) Step 4.4, It is an early warning indicator for the weak impact danger area. It is an early warning indicator for medium impact risk areas. It is an early warning indicator for strong impact risk areas; Step 4.5: For areas predicted to be free of impact danger, normal excavation shall be carried out; for areas predicted to be in weak impact danger or above, decompression and danger relief measures shall be taken in advance according to the impact danger degree; Step 5: During tunnel excavation, dynamically monitor and draw impact hazard prediction curves, and perform on-site zoned pressure relief; The specific process is: Step 5.1, (1) During the excavation of the target tunnel, if the microseismic and stress monitoring system has not yet been deployed, the prediction is based on the comprehensive prediction curve A of rock burst danger in different areas during the excavation of the adjacent empty tunnel obtained in step 3.4; (2) During the excavation of the target tunnel, if only a microseismic monitoring system is deployed, all microseismic events in the target tunnel are collected and saved in the format of time, XYZ coordinates, and event energy; the distance between the target tunnel opening and the stop line is taken as the length L, and the range S on the left and right sides of the wall of the target tunnel close to the adjacent working face is taken as the width. The rectangular target area is enveloping, and the target tunnel opening is taken as the starting point. The grid is divided with a spacing D along the working face direction, and the total energy of the microseismic events falling in each grid interval is counted. ,Will Substituting into formula (5), we can obtain the warning stress value at each statistical point in the total energy distribution curve of the microseismic event: ,by is the horizontal axis, As the vertical coordinate, draw the comprehensive prediction curve B of rock burst danger in different areas during the excavation of adjacent empty tunnels, and make predictions based on the prediction curve B; (3) During the excavation of the target tunnel, if the microseismic monitoring system and coal stress gauges have been arranged according to the process of steps 1.1 to 1.2, repeat steps 1.3 to 1.5 and obtain the basic stress values ​​of each area in the current excavation tunnel. And according to (2), the total energy of microseismic events falling in each grid interval is obtained Substituting into formula (5), we can obtain the warning stress value at each statistical point in the total energy distribution curve of the microseismic event: ,by is the horizontal axis, As the vertical coordinate, the comprehensive prediction curve C of rock burst danger in different areas during the excavation of adjacent empty tunnels is drawn, and the prediction is carried out based on the prediction curve C; Step 5.2, repeat steps 4.1 to 4.4 to obtain early warning indicators for weak, medium and strong impact danger areas. For areas predicted by the prediction curve to be at or above weak impact danger, the drilling cuttings method is used for supplementary monitoring at the side of the roadway; If the amount of diamond powder does not exceed the standard, , the comprehensive prediction curve of impact risk will not be adjusted; If the amount of drilling cuttings exceeds the standard, , the maximum excess multiple, the average excess value, and the difficulty of drilling are used to measure the severity of the excess of drill dust. According to each indicator, a stress adjustment coefficient is selected, and three stress adjustment coefficients are obtained. The three stress adjustment coefficients are added together to obtain the adjustment coefficient of the warning stress value at the corresponding measuring point. , the stress adjustment coefficient corresponding to each indicator is shown in Table 1: Table 1

[0016] in, The maximum amount of diamond powder measured. is the standard value of diamond powder content, is the maximum drilling depth, The standard hole depth for drilling is It is the sum of the stress adjustment coefficients corresponding to the three indicators item by item; Step 5.3: Adjustment coefficient of the warning stress value at the corresponding measuring point obtained in step 5.2 Adjust the warning stress value to obtain the adjusted warning stress value (adjusted warning stress value = (1+ ) ), according to the adjusted warning stress value, the comprehensive prediction curve of rock burst danger in different areas during the excavation of adjacent empty tunnels is redrawn as the final prediction curve; Step 5.4: Based on the prediction results, the on-site area is depressurized and treated.

[0017] Step 5 can provide dynamic early warning during the excavation of the target tunnel, greatly improving the safety during the excavation of the target tunnel.

[0018] Example 3 The impact hazard early warning method during tunneling of adjacent empty tunnels based on trend regression analysis of the present invention is specifically implemented according to the following steps: Step 1: During the mining period of the working face adjacent to the target tunnel, stress gauges are deployed to monitor the stress of the coal seam and draw a regional basic stress curve; The specific process is: Step 1.1, such as Figure 2As shown, the target tunnel to be warned is determined to be the adjacent tunnel A. Before the working face B adjacent to the adjacent tunnel A is affected by mining, n groups of coal body stress gauges are set at equal intervals on the mining side along the working face with the mining working face as the starting position. The coal body stress gauges are arranged in the mining tunnel B2, and the sensitive components of the n groups of coal body stress gauges penetrate into the stress concentration area of ​​the coal wall. Each group of coal body stress gauges has two, one for shallow stress measurement and one for deep stress measurement. The distance between the two coal body stress gauges in each group is 2m. Along the working face direction, the coal body stress gauges for measuring deep stress are numbered 1, 2, 3, ..., n, and the coal body stress gauges for measuring shallow stress are numbered 1, 2, 3, ..., n. ’ , 2 ’ , 3 ’ ,…,n ’ ; The depth of shallow stress measurement is 9m, the depth of shallow stress measurement is 15m (coal seam mining height is 5m), the spacing between two adjacent groups of coal body stress gauges is 30m, and they are arranged in the whole tunnel; Step 1.2, during the mining of the working face, continuously collect the monitoring data of the media stress gauges. When the distance between the mining of the working face and the first group of coal body stress gauges is ≤15m, remove the first group of coal body stress gauges and install them behind the last group of media stress gauges with the spacing unchanged, so as to always maintain an advanced monitoring range of at least 300m in front of the working face; Step 1.3, extract the maximum stress values ​​measured by the coal body stress gauge for measuring deep stress and the coal body stress gauge for measuring shallow stress from the initial installation to the removal, and record the maximum deep stress value as , the maximum value of shallow stress is recorded as , read the distance between each coal body stress gauge measuring deep stress and the advance working face , read the distance between each coal body stress gauge measuring shallow stress and the advance working face ; Step 1.4, calculate the average value of the maximum stress and distance average , the expression is as follows: (1) (2); Step 1.5, is the horizontal axis, is the vertical axis, such as Figure 3 As shown, the regional foundation stress curve is drawn; Step 2, during the mining period of the working face adjacent to the target roadway, all microseismic events of the working face are collected, the target area is delineated, and a grid is divided in the target area, and a total energy distribution curve of the microseismic events is drawn according to the microseismic events in the target area; The specific process is: Step 2.1, during the mining period of the working face adjacent to the target roadway, all microseismic events of the working face are collected and saved in the format of time, XYZ coordinates, and event energy; Step 2.2, the distance between the cut hole and the stop line of the working face adjacent to the target tunnel is taken as the length, which is 1000m, and the range of 80m on both sides of the wall of the mining tunnel close to the adjacent working face is taken as the width, which is 160m. Figure 4 As shown, the target area of ​​the envelope drawing rectangle, the mining roadway is located between the target roadway and the working face adjacent to the target roadway; Step 2.3: Taking the cut hole of the working face as the starting point, divide the grids along the working face with a spacing of 20m, a total of 50 grids, and count the total energy of microseismic events falling in each grid interval. ; Step 2.4, is the horizontal axis, is the vertical axis, such as Figure 5 As shown, the total energy distribution curve of microseismic events is drawn along the strike of the working face; Step 3, obtaining a rock burst hazard prediction curve based on the total energy distribution curve of microseismic events and the regional foundation stress curve; The specific process is: Step 3.1: Calculate the mathematical expectation of the total energy of microseismic events in each grid interval according to formula (4): =316.37J; Step 3.2, align the abscissa axis of the regional basic stress curve drawn in step 1 with the total energy distribution curve of microseismic events drawn in step 2, the strike grid spacing of the basic stress curve is 30m, and the strike grid spacing of the microseismic total energy relationship curve is 20m, and the basic stress curve with a statistical interval of 20m is obtained through interpolation calculation; Step 3.3: Calculate the warning stress value at each statistical point in the total energy distribution curve of the microseismic event according to formula (5): ; Step 3.4, is the horizontal axis, is the vertical axis, such as Figure 6 As shown, a comprehensive prediction curve A of rock burst danger in different areas during tunneling adjacent to empty tunnels is drawn; Step 4: Based on the data of rock burst or high energy events in the mine, the comprehensive early warning indicators of dangerous areas of different levels are divided to carry out advanced treatment of dangerous areas; The specific process is: Step 4.1, collect all data of the working face where rock burst or high energy event occurs in the mine adjacent to the empty tunnel A; Step 4.2: No rock burst accident or high-energy event with obvious damage occurred in this mine. The microseismic event with the highest energy detected in the mine is taken as the characteristic case event. The maximum stress value of the area within 1 day before and after the event is read. is 14.63MPa, with the area where the incident occurred as the center point. Figure 7 As shown in the figure, the microseismic events within the range of 80 degrees to the left and back of the working face and 10 degrees to the front and back of the working face are counted, and the total energy of the microseismic events is calculated. is 9866.43J; Step 4.3: Calculate the warning stress value according to formula (6): 23.37MPa; Step 4.4, such as Figure 8 As shown, =11.69MPa is the early warning indicator of the weak impact danger zone. =17.53MPa is the early warning indicator for the medium impact danger zone. =23.37MPa is the early warning indicator for the strong impact danger zone; Step 4.5: For those predicted to be in the area without impact danger, normal excavation is carried out; for the two weak impact danger areas of 400m and 520m in the adjacent empty tunnel, advance warning is carried out and pressure relief measures need to be taken in advance before excavation; The above steps are used to carry out advance warning before excavation; Step 5: During tunnel excavation, dynamically monitor and draw impact hazard prediction curves, and perform on-site zoned pressure relief; The specific process is: Step 5.1, (1) The adjacent empty tunnel A has been excavated for 0 m, and the microseismic and stress monitoring systems have not yet been deployed. The prediction is based on the comprehensive prediction curve A of rock burst danger in different areas during the adjacent empty tunnel excavation obtained in step 3.4; (2) After tunneling 200 m, only the microseismic monitoring system is deployed to collect all microseismic events in tunnel A and save them in the format of time, XYZ coordinates, and event energy. The distance between the cut hole and the stop line of tunnel A is taken as the length, which is 1000 m. The width is 80 m on each side of the wall of tunnel A close to the adjacent working face, which is 160 m. Fig. 9 As shown in the figure, the target area of ​​the envelope is a rectangle. The cut eye of the adjacent empty roadway A is taken as the starting point, and the grid is divided into 50 grids with a spacing of 20m along the working face. The total energy of the microseismic events falling in each grid interval is counted. ,Will Substituting into formula (5), we can obtain the warning stress value at each statistical point in the total energy distribution curve of the microseismic event: ,by is the horizontal axis, As the vertical coordinate, the comprehensive prediction curve of rock burst danger in different areas during the excavation of adjacent empty tunnels is drawn, such as Fig.10 As shown, for the microseismic events in the 0-200m section, the calculation results of the newly monitored microseismic curve shall prevail, and for the 200-1000m section that has not been excavated, the prediction curve of prediction curve A shall still be used; (3) After 400 m of excavation of adjacent tunnel A, the microseismic monitoring system and coal stress gauges have been arranged according to the process of steps 1.1 to 1.2. Then, steps 1.3 to 1.5 are repeated to obtain the basic stress values ​​of each area of ​​the current excavation tunnel. And according to (2), the total energy of microseismic events falling in each grid interval is obtained Substituting into formula (5), we can obtain the warning stress value at each statistical point in the total energy distribution curve of the microseismic event: ,by is the horizontal axis, As the vertical coordinate, the comprehensive prediction curve of rock burst danger in different areas during the excavation of adjacent empty tunnels is drawn, such as Fig.11 As shown, for the microseismic events in the 0-400m section, the calculation results of the newly monitored microseismic curve shall prevail, and for the 400-1000m section that has not been excavated, the prediction curve of prediction curve A shall still be used; (4) The adjacent empty tunnel is excavated for 600 m. The process is the same as (3). For the microseismic events in the excavation section 0-600 m, the calculation results of the newly monitored microseismic curve shall prevail, such as Fig.12 As shown, the prediction curve of prediction curve A is still used for the unexcavated 600-1000m section; Step 5.2: There are two areas with weak impact danger or above at 400m and 540-560m of the advance working face. It is necessary to use the drill cuttings method to conduct supplementary monitoring of these two areas. The drilling spacing is 5m. Drilling measurements are carried out in the warning area and the range 5m before and after it. A total of 7 groups of drill cuttings holes were constructed at 540-560m. The drill dust did not exceed the standard, and the maximum drill dust volume was Therefore, the impact hazard comprehensive prediction curve is not adjusted; 3 groups of drill cuttings holes are constructed at 400m, and the drill cuttings of the 3 groups are 20.8kg, 24.7kg and 18.9kg respectively. , the maximum excess multiple is 4.94, the corresponding stress adjustment coefficient of this indicator is 0.4, the average excess value is 16.46kg, the corresponding stress adjustment coefficient of this indicator is 0.4, the drilling depth of the borehole is 15m, which can reach the standard hole depth, and the stress adjustment coefficient is 0, so the stress adjustment coefficient at the 400m measuring point is .

[0019] Step 5.3, predicted stress value of the point where the cuttings exceed the standard at 400m , dynamically adjust the impact risk prediction curve; Step 5.4, according to the prediction results, the site is zoned for decompression and treatment, with the point at 400m where the drill cuttings exceed the standard being the focus of treatment.

Claims

1. A method for early warning of impact danger during tunneling adjacent to empty tunnels based on trend regression analysis, characterized in that: Follow the steps below to implement it: Step 1: During the mining period of the working face adjacent to the target tunnel, stress gauges are deployed to monitor the stress of the coal seam and draw a regional basic stress curve; Step 2, during the mining period of the working face adjacent to the target roadway, all microseismic events of the working face are collected, the target area is delineated, and a grid is divided in the target area, and a total energy distribution curve of the microseismic events is drawn according to the microseismic events in the target area; Step 3, obtaining a rock burst hazard prediction curve based on the total energy distribution curve of microseismic events and the regional foundation stress curve; Step 4: Based on the data of rock burst or high energy events in the mine, the comprehensive early warning indicators of dangerous areas of different levels are divided to carry out advanced treatment of dangerous areas; Step 5: During tunnel excavation, dynamically monitor and draw impact hazard prediction curves, and perform on-site zone pressure relief.

2. The method for early warning of impact danger during tunnel excavation adjacent to empty tunnels based on trend regression analysis according to claim 1 is characterized in that: The specific process of step 1 is: Step 1.1, determine the target roadway to be warned, before the working face adjacent to the target roadway is affected by mining, take the mining working face as the starting position and set n groups of coal body stress gauges at equal intervals along the working face, and the sensitive components of the n groups of coal body stress gauges penetrate into the stress concentration area of ​​the coal wall; Each group of coal body stress gauges has two, one for shallow stress measurement and one for deep stress measurement. The distance between the two coal body stress gauges in each group is ≤2m. The coal body stress gauges for measuring deep stress are numbered 1, 2, 3, ..., n along the working face direction, and the coal body stress gauges for measuring shallow stress are numbered 1, 2, 3, ..., n. ’ , 2 ’ , 3 ’ ,…,n ’ ; Step 1.2, during the mining period of the working face, continuously collect monitoring data of the media stress gauges, and when the working face is mined close to the first group of coal body stress gauges, remove the first group of coal body stress gauges and install them behind the last group of media stress gauges with the spacing remaining unchanged; Step 1.3, extract the maximum stress values ​​measured by the coal body stress gauge for measuring deep stress and the coal body stress gauge for measuring shallow stress from the initial installation to the removal, and record the maximum deep stress value as , the maximum value of shallow stress is recorded as , read the distance between each coal body stress gauge measuring deep stress and the advance working face , read the distance between each coal body stress gauge measuring shallow stress and the advance working face ; Step 1.4, calculate the average value of the maximum stress and distance average , the expression is as follows: （1） （2）； Step 1.5, is the horizontal axis, As the vertical axis, draw the regional foundation stress curve.

3. The method for early warning of impact danger during tunnel excavation adjacent to empty tunnels based on trend regression analysis according to claim 2 is characterized in that: In step 1.1, the depth of shallow stress measurement is ≥1.5h, and the depth of shallow stress measurement is ≥3h, where h is the mining height of the coal seam. The distance between two adjacent groups of coal stress gauges is ≤30m, and the number of groups of coal stress gauges is ≥10.

4. The method for early warning of impact danger during tunnel excavation adjacent to empty tunnels based on trend regression analysis according to claim 1 is characterized in that: The specific process of step 2 is: Step 2.1, during the mining period of the working face adjacent to the target roadway, all microseismic events of the working face are collected and saved in the format of time, coordinates, and event energy; Step 2.2, taking the distance between the cut hole and the stop mining line of the working face adjacent to the target roadway as the length L, taking the range of the left and right sides S of the wall of the mining roadway close to the adjacent working face as the width, enveloping and drawing a rectangular target area, the mining roadway is located between the target roadway and the working face adjacent to the target roadway; Step 2.3: Taking the cut eye of the working face as the starting point, divide the grids along the working face with a spacing of D, and count the total energy of microseismic events falling in each grid interval. ; The number of grids N and the spacing D satisfy: (3); Step 2.4, is the horizontal axis, The vertical coordinate is used to draw the total energy distribution curve of microseismic events along the direction of the working face.

5. The method for early warning of impact danger during tunnel excavation adjacent to empty tunnels based on trend regression analysis according to claim 4 is characterized in that: The specific process of step 3 is: Step 3.1: Count the total energy of all microseismic events within the rectangular target area. , and the mathematical expectation of the total energy of microseismic events in each grid interval is calculated according to formula (4): ; （4） Step 3.2: Align the regional basic stress curve drawn in step 1 with the horizontal axis of the total energy distribution curve of the microseismic event drawn in step 2, and read the stress value corresponding to each statistical point in the total energy distribution curve of the microseismic event respectively. ; Step 3.3: Calculate the warning stress value at each statistical point in the total energy distribution curve of the microseismic event , the expression is: （5） Step 3.4, is the horizontal axis, With 20° as the vertical coordinate, a comprehensive prediction curve A for rock burst danger in different areas during tunneling in adjacent empty tunnels is drawn.

6. The method for early warning of impact danger during tunnel excavation adjacent to empty tunnels based on trend regression analysis according to claim 5 is characterized in that: The specific process of step 4 is: Step 4.1, collect all data of the working face where rock burst or high energy event occurs in the mine where the target tunnel is located; Step 4.2: Select a characteristic case event and read the maximum stress value of the event area within one day before and after the characteristic case event. Taking the area where the event occurred as the center point, count the microseismic events within the range of S distances to the left and back of the working face and D / 2 distances before and after the working face, and calculate the total energy of the microseismic events ; Step 4.3: Calculate the warning stress value according to formula (6): ; （6） Step 4.4, It is an early warning indicator for the weak impact danger area. It is an early warning indicator for medium impact risk areas. It is an early warning indicator for strong impact risk areas; Step 4.5: For areas predicted to be without impact hazard, excavation shall proceed normally; for areas predicted to be with weak impact hazard or above, decompression and hazard relief measures shall be taken in advance according to the degree of impact hazard.

7. The method for early warning of impact danger during tunnel excavation adjacent to empty tunnels based on trend regression analysis according to claim 6 is characterized in that: In step 4.2, when there is no rock burst accident or high-energy event that causes obvious damage in the mine, the microseismic event with the highest energy monitored in the mine is taken as the characteristic case event; When only one rock burst accident or a high-energy event with obvious damage occurs in a mine, this event is regarded as a characteristic case event; When a mine has multiple rock burst accidents or high-energy events with obvious damage, each event needs to be treated as a characteristic case event, and the minimum value of all warning stress values ​​obtained is used to divide the warning indicators.

8. The method for early warning of impact danger during tunneling adjacent to empty tunnels based on trend regression analysis according to claim 6 is characterized in that: The specific process of step 5 is: Step 5.1, (1) During the excavation of the target tunnel, if the microseismic and stress monitoring system has not yet been deployed, the prediction is based on the comprehensive prediction curve A of rock burst danger in different areas during the excavation of the adjacent empty tunnel obtained in step 3.4; (2) During the excavation of the target tunnel, if only a microseismic monitoring system is deployed, all microseismic events in the target tunnel are collected and saved in the format of time, XYZ coordinates, and event energy; The distance between the target tunnel opening and the stop mining line is taken as the length L, and the range of the left and right sides of the wall of the target tunnel close to the adjacent working face is taken as the width. The rectangular target area is enveloping. The target tunnel opening is taken as the starting point, and the grid is divided with a spacing D along the working face. The total energy of the microseismic events falling in each grid interval is counted. , substituted into formula (5), the warning stress value at each statistical point in the total energy distribution curve of the microseismic event is obtained ,by is the horizontal axis, As the vertical coordinate, draw the comprehensive prediction curve B of rock burst danger in different areas during the excavation of adjacent empty tunnels, and make predictions based on the prediction curve B; (3) During the excavation of the target tunnel, if the microseismic monitoring system and coal stress gauges have been arranged according to the process of steps 1.1 to 1.2, repeat steps 1.3 to 1.5 and obtain the basic stress values ​​of each area in the current excavation tunnel. And according to (2), the total energy of microseismic events falling in each grid interval is obtained Substituting into formula (5), we can obtain the warning stress value at each statistical point in the total energy distribution curve of the microseismic event: ,by is the horizontal axis, As the vertical coordinate, the comprehensive prediction curve C of rock burst danger in different areas during the excavation of adjacent empty tunnels is drawn, and the prediction is carried out based on the prediction curve C; Step 5.2, repeat steps 4.1 to 4.4 to obtain early warning indicators for weak, medium and strong impact danger areas. For areas predicted by the prediction curve to be at or above weak impact danger, the drilling cuttings method is used for supplementary monitoring at the side of the roadway; If the amount of diamond powder does not exceed the standard, , the comprehensive prediction curve of impact risk will not be adjusted; If the amount of drilling cuttings exceeds the standard, , the maximum excess multiple, the average excess value, and the difficulty of drilling are used to measure the severity of the drill dust excess. According to each indicator, a stress adjustment coefficient is selected, and three stress adjustment coefficients are obtained. The three stress adjustment coefficients are added together to obtain the adjustment coefficient of the warning stress value at the corresponding measuring point. The stress adjustment coefficient corresponding to each indicator is shown in Table 1: Table 1 in, The maximum amount of diamond powder measured. is the standard value of diamond powder content, is the maximum drilling depth, The standard hole depth for drilling is It is the sum of the stress adjustment coefficients corresponding to the three indicators item by item; Step 5.3: Adjustment coefficient of the warning stress value at the corresponding measuring point obtained in step 5.2 The warning stress value is adjusted to obtain the adjusted warning stress value, and the comprehensive prediction curve of rock burst danger in different areas during the excavation of adjacent empty tunnels is redrawn according to the adjusted warning stress value as the final prediction curve; Step 5.4: Based on the prediction results, the on-site area is depressurized and treated.

9. The method for early warning of impact danger during tunneling adjacent to empty tunnels based on trend regression analysis according to claim 8 is characterized in that: In step 5.3, the adjusted warning stress value = (1+ ) .

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