Rock burst prevention method for multi-roadway driving and pressure relief in coal seam with rock burst

Abstract

The application discloses a kind of rock burst coal seam multi-lane driving pressure relief anti-burst methods, comprising: determining the target horizon and position of pressure relief measure lane;According to the design of pressure relief measure lane blasting path and parameter;Driving pressure relief measure lane;The area where pressure relief measure lane is located is implemented intensive deep hole presplitting blasting;Drive the coal seam roadway in the presplitting blasting coverage range of pressure relief measure lane.The rock burst coal seam multi-lane driving pressure relief anti-burst method disclosed in the application, after the basic roof blasting presplitting above the first coal lane and the second coal lane of the rock burst coal seam, the coal seam roadway is driven in the blasting presplitting coverage range, the coal seam roadway driving and using period are all in low stress area, in protected state, reduce the dynamic and static load source of inducing impact start, improve the impact threshold of rock burst, the danger degree of rock burst is significantly reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of coal mining, in particular to a multi-roadway driving pressure-relief and rock burst prevention method for a rock burst coal seam. BACKGROUND

[0002] With the deep mining of coal mines in China, the in-situ stress is at a high level, and the structures such as folds and faults are distributed in the minefield, so the in-situ stress and the structure stress form a high concentrated stress foundation, and the supporting pressure is superimposed during the roadway driving process, thereby inducing rock burst.

[0003] The pressure relief of the driving roadway is usually carried out by local pressure relief measures such as coal seam blasting and large-diameter drilling. On the one hand, the driving working face region is concentratedly arranged with large-scale machinery, construction tools and supporting materials, and the pressure relief space is limited, so the conventional pressure relief measures are lagging behind, causing the existence of a pressure relief blind area in the driving working face and the side part within a certain distance behind the driving working face. On the other hand, the conventional local pressure relief measures have a limited pressure relief range, and multiple rounds of pressure relief are often required during the roadway driving process, resulting in low pressure relief efficiency. Before the roadway driving, a pressure relief measure roadway can be pre-driven in the basic roof of the coal seam in the region to be driven, and intensive deep-hole blasting pre-splitting is carried out in the pressure relief measure roadway to reduce the in-situ stress and structure stress level of the region to be driven, so that the region to be driven is in a pressure relief protection zone, thereby effectively reducing the possibility of rock burst during the driving of the rock burst coal seam roadway. SUMMARY

[0004] The present application aims to provide a multi-roadway driving pressure-relief and rock burst prevention method for a rock burst coal seam, so as to solve the problems of the conventional pressure relief measures during the driving of the rock burst coal seam roadway, such as the existence of a pressure relief blind area, discontinuous pressure relief and heavy pressure relief tasks.

[0005] The present application provides a multi-roadway driving pressure-relief and rock burst prevention method for a rock burst coal seam, comprising:

[0006] determining the target horizon and position of the pressure relief measure roadway;

[0007] designing the blasting path and parameters of the pressure relief measure roadway;

[0008] driving the pressure relief measure roadway;

[0009] carrying out intensive deep-hole pre-splitting blasting on the region where the pressure relief measure roadway is located;

[0010] driving the coal seam roadway within the pre-splitting blasting coverage range of the pressure relief measure roadway.

[0011] Preferably, the determination of the target horizon and position of the pressure relief measure roadway specifically comprises the following steps:

[0012] selecting the basic roof as the target horizon according to the drilling columnar chart;

[0013] The first coal roadway and the second coal roadway are arranged in the coal seam, and the first coal roadway and the second coal roadway are parallel to each other, wherein the first coal roadway comprises a first excavated roadway and a first to-be-excavated roadway, the first excavated roadway has been excavated, the first to-be-excavated roadway is waiting to be excavated, and the first to-be-excavated roadway is located on an extension line of the first excavated roadway; the second coal roadway comprises a second excavated roadway and a second to-be-excavated roadway, the second excavated roadway has been excavated, the second to-be-excavated roadway is waiting to be excavated, and the second to-be-excavated roadway is located on an extension line of the second excavated roadway;

[0014] The basic roof at a middle position above the first coal roadway and the second coal roadway is determined as the excavation position of the pressure relief measure roadway.

[0015] Preferably, the step of designing a blasting path and parameters according to the pressure relief measure roadway comprises the following steps:

[0016] Step B1: selecting a section of the pressure relief measure roadway as a starting section according to the target layer thickness, and setting a drilling field on the starting section, and implementing a first blasting hole and a second blasting hole on both sides of the drilling field, and the first blasting hole and the second blasting hole are arranged at both ends of the drilling field of the pressure relief measure roadway to form a fan shape;

[0017] Step B2: charging the first blasting hole and the second blasting hole to form a charging section, and the longitudinal projection of the charging section of the first blasting hole and the second blasting hole falls in the projection area of the cross section of the to-be-excavated area where the first to-be-excavated roadway and the second to-be-excavated roadway are located, so that the to-be-excavated area is within the blasting pre-cracking coverage range of the basic roof;

[0018] Step B3: taking the starting section as a starting point, and setting a plurality of drilling fields with an adjacent interval of 8 m, and implementing a first blasting hole and a second blasting hole on both sides of the drilling field, and the first blasting hole and the second blasting hole are arranged at both ends of the drilling field of the pressure relief measure roadway to form a fan shape;

[0019] Step B4: repeating step B2, and charging a first blasting hole and a second blasting hole on both sides of each drilling field to form a charging section.

[0020] Preferably, the step of implementing intensive deep hole pre-cracking blasting on the area where the pressure relief measure roadway is located comprises the following steps:

[0021] Step D1: implementing intensive blasting pre-cracking on the thick and hard sandstone of the basic roof on the coal seam on both sides of the pressure relief measure roadway, and ensuring that the basic roof pre-cracking range covers the to-be-excavated area where the first to-be-excavated roadway of the first coal roadway and the second to-be-excavated roadway of the second coal roadway are located in the rock burst coal seam;

[0022] Step D2: after the blasting at the previous position is completed, the blasting at the next position is carried out, and the overlying basic roof pre-cracking work on the entire to-be-excavated area is completed;

[0023] Step D3: repeat the step D2 until the overall weakening of the basic roof is achieved, wherein cracks are formed on the charging section of the first blast hole, the cracks including radial cracks and hoop cracks, so that adjacent first blast holes are connected with each other; cracks are formed on the charging section of the second blast hole, the cracks including radial cracks and hoop cracks, so that adjacent second blast holes are connected with each other to avoid causing a blasting pre-splitting blind area.

[0024] Preferably, the tunneling of the coal seam roadway within the pre-splitting blasting coverage of the pressure relief measure roadway specifically comprises the following steps:

[0025] Tunneling is performed in the low stress area within the blasting pre-splitting coverage of the basic roof, and the coal seam roadway is tunneled, so that the tunneling working face is in the low stress area as much as possible to avoid stress concentration to cause an increase in impact risk.

[0026] Compared with the prior art, the present application has the following beneficial effects:

[0027] The present application discloses a method for pressure relief and impact prevention in multi-lane tunneling in a coal seam with rock burst, which comprises the following steps: before tunneling in a coal seam, a pressure relief measure lane is pre-tunneled in the basic roof above the coal seam to be tunneled, and intensive deep hole blasting pre-splitting is performed on the basic roof, which is beneficial to relieve the heavy pressure relief and impact prevention work pressure during tunneling, regionally reduce the original rock stress and tectonic stress level of the tunneling area, and realize smooth tunneling in a low stress area, thereby significantly reducing the stress concentration degree and impact risk during tunneling. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 A multi-lane tunneling planar layout for a coal seam with rock burst is provided for the embodiment 1 of the present application.

[0029] Figure 2 A deep hole blasting pre-splitting profile of a thick hard rock layer above a to-be-tunneled lane without development is provided for the embodiment 1 of the present application.

[0030] Figure 3 A deep hole blasting pre-splitting profile of a thick hard rock layer above a to-be-tunneled lane with development is provided for the embodiment 1 of the present application.

[0031] Explanation of reference signs: 11-first excavated roadway, 12-second excavated roadway, 21-first to-be-excavated roadway, 22-second to-be-excavated roadway; 3-pressure relief measure roadway; 41-first blasting hole, 42-second blasting hole; 5-radial crack, 6-circumferential crack, 100-coal seam, 200-direct roof, 300-basic roof; σ c -critical impact load, σ1-lateral support pressure curve of roadway without carrying out basic roof blasting pre-splitting, σ2-lateral support pressure curve of roadway with carrying out basic roof blasting pre-splitting. DETAILED DESCRIPTION

[0032] The following examples are used to illustrate the present application, but are not used to limit the scope of the present application.

[0033] The present application discloses a kind of impact ground pressure coal seam multi-lane excavation pressure relief anti-burst method, in the basic roof 300 in the middle position of first coal lane and second coal lane above coal seam 100 multi-lane excavation, pre-excavation pressure relief measure roadway 3 in basic roof 300 on coal seam 100 carries out dense deep hole blasting pre-splitting in pressure relief measure roadway 3, ahead reduces the stress level of rock stress and structure stress in the area to be excavated of roadway, so as to realize the smooth excavation of roadway in low stress area, so as to greatly reduce stress concentration degree and impact risk during roadway excavation.

[0034] Example 1

[0035] Example 1 provides a kind of impact ground pressure coal seam multi-lane excavation pressure relief anti-burst method, applied to coal mine, the coal mine includes coal seam 100, there is direct roof 200 above coal seam 100, and there is basic roof 300 above direct roof 200, wherein, basic roof 300 is composed of thick hard sandstone, can be used as thick hard roof, including the following steps:

[0036] Step A: determine the target horizon and position of pressure relief measure roadway 3;

[0037] Step A1: according to the drilling columnar chart, select basic roof 300 as target horizon, as shown in Figure 2 and Figure 3 ;

[0038] Specifically, the thickness of coal seam 100 is 8.0m, the thickness of direct roof 200 is 5.7m, and the thickness of basic roof 300 is 15.2m.

[0039] Step A2: A first coal roadway and a second coal roadway are set up within the coal seam 100. The first coal roadway and the second coal roadway are parallel to each other. The first coal roadway includes a first excavated roadway 11 and a first roadway 21 to be excavated. The first excavated roadway 11 has been completed, and the first roadway 21 to be excavated is waiting to be excavated. The first roadway 21 to be excavated is located on the extension line of the first excavated roadway 11. The second coal roadway includes a second excavated roadway 12 and a second roadway 22 to be excavated. The second excavated roadway 12 has been completed, and the second roadway 22 to be excavated is waiting to be excavated. The second roadway 22 to be excavated is located on the extension line of the second excavated roadway 12.

[0040] Specifically, the distance between the first and second coal roadways is 40m.

[0041] Step A3: Determine the basic top 300, located at the midpoint above the first and second coal roadways, as the excavation position for the pressure relief roadway 3.

[0042] Specifically, the excavation location of the pressure relief tunnel 3 is above the first and second coal tunnels, and is 10m above the coal seam 100.

[0043] Step B: Design the blasting path and parameters based on the pressure relief measures in tunnel 3;

[0044] Step B1: Select a section of the pressure relief tunnel 3 as the starting section according to the target layer thickness, and set up a drilling site on the starting section. First blasting hole 41 and second blasting hole 42 are respectively implemented on both sides of the drilling site. The first blasting hole 41 and second blasting hole 42 are respectively set at both ends of the drilling site of the pressure relief tunnel 3 to form a fan shape.

[0045] Step B2: The first blasting hole 41 and the second blasting hole 42 are charged to form a charging section. The longitudinal projection of the charging section of the first blasting hole 41 and the second blasting hole 42 along the pressure relief tunnel 3 falls on the projection area of ​​the cross section of the tunnel to be excavated where the first tunnel to be excavated 21 and the second tunnel to be excavated 22 are located, so that the tunnel to be excavated is within the basic top blasting pre-splitting coverage area.

[0046] Specifically, the first blasting hole 41 and the second blasting hole 42 are 32m deep, with a charge length of 21m, an inclination angle of 7°, and a charge weight of 63kg, ensuring that the charge sections of the first blasting hole 41 and the second blasting hole 42 cover the peak support pressure area formed by the coal seam roadway excavation. Specifically, the drilling site spacing is set at 8m, i.e., one drilling site every 8m.

[0047] Step B3: Starting from the initial cross section, multiple drilling sites are set up with an adjacent spacing of 8m. First blasting holes 41 and second blasting holes 42 are respectively implemented on both sides of the drilling site. The first blasting holes 41 and second blasting holes 42 are respectively set at both ends of the drilling site in the pressure relief tunnel 3 to form a fan shape.

[0048] Step B4: Repeat step B2 to load explosives into one blasting hole 41 and the second blasting hole 42 on both sides of each drilling site to form a charging section;

[0049] Step C: Excavation of decompression relief measures in tunnel 3;

[0050] Step D: Conduct intensive deep-hole pre-splitting blasting in the area where the pressure relief tunnel 3 is located;

[0051] Step D1: On both sides of the pressure relief roadway 3, carry out intensive blasting pre-splitting on the thick hard sandstone of the basic roof 300 on the coal seam 100 to ensure that the pre-splitting range of the basic roof 300 covers the area to be excavated where the first roadway 21 of the first coal roadway and the second roadway 22 of the second coal roadway in the rockburst coal seam 100 are located.

[0052] Step D2: After completing the blasting at the previous location, proceed with the blasting at the next location until the pre-splitting work of the overlying roof of the entire area to be excavated is completed;

[0053] Step D3: Repeat step D2 until the overall weakening of the basic top 300 is achieved. During this process, a crack is formed in the charging section of the first blast hole 41, the crack including radial cracks 5 and circumferential cracks 6, allowing adjacent first blast holes 41 to communicate with each other; a crack is also formed in the charging section of the second blast hole 42, the crack including radial cracks 5 and circumferential cracks 6, allowing adjacent second blast holes 42 to communicate with each other, thus avoiding the creation of a pre-fracture blind zone. Figure 1 and Figure 3 As shown.

[0054] Step E: Excavate the coal seam roadway within the pre-splitting blasting coverage area of ​​the pressure relief measure roadway 3:

[0055] Excavation is carried out in the low-stress zone within the blasting pre-splitting coverage area of ​​the basic top 300, and the coal seam roadway is excavated so that the working face is located in the low-stress zone as much as possible to avoid stress concentration and increased impact risk.

[0056] During the tunneling and use of the coal seam roadway, it is within the coverage area of ​​the overlying basic roof blasting and pre-splitting.

[0057] During the excavation of coal seam roadways, the peak value of lateral support pressure decreases and the peak value shifts to deeper areas, indicating that the coal seam roadway is in a low-stress zone.

[0058] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A method for depressurization and anti-rockburst prevention in multi-roadway tunneling of coal seams prone to rockburst, characterized in that, include: Step A: Determine the target stratum and location of the decompression measures tunnel (3), including the following specific steps: Step A1: Based on the borehole columnar section, select the basic top (300) as the target layer; Step A2: A first coal roadway and a second coal roadway are set up in the coal seam (100). The first coal roadway and the second coal roadway are parallel to each other. The first coal roadway includes a first excavated roadway (11) and a first roadway to be excavated (21). The first excavated roadway (11) has been completed and the first roadway to be excavated (21) is waiting to be excavated. The first roadway to be excavated (21) is located on the extension line of the first excavated roadway (11). The second coal roadway includes a second excavated roadway (12) and a second roadway to be excavated (22). The second excavated roadway (12) has been completed and the second roadway to be excavated (22) is waiting to be excavated. The second roadway to be excavated (22) is located on the extension line of the second excavated roadway (12). Step A3: Determine the basic top (300) at the middle position above the first and second coal roadways as the excavation position of the pressure relief roadway (3); Step B: Design the blasting path and parameters based on the pressure relief tunnel (3), including the following specific steps: Step B1: Select a section of the pressure relief tunnel (3) as the starting section according to the thickness of the target layer, and set up a drilling site on the starting section. First blasting hole (41) and second blasting hole (42) are respectively implemented on both sides of the drilling site. The first blasting hole (41) and the second blasting hole (42) are respectively set at both ends of the drilling site of the pressure relief tunnel (3) to form a fan shape. Step B2: The first blasting hole (41) and the second blasting hole (42) are charged to form a charging section. The longitudinal projection of the charging section of the first blasting hole (41) and the second blasting hole (42) along the pressure relief tunnel (3) falls on the projection area of ​​the cross section of the tunnel to be excavated where the first tunnel to be excavated (21) and the second tunnel to be excavated (22) are located, so that the tunnel to be excavated is within the basic top blasting pre-splitting coverage area. Step B3: Starting from the initial section, multiple drilling sites are set up with an adjacent spacing of 8m. First blasting hole (41) and second blasting hole (42) are respectively implemented on both sides of the drilling site. The first blasting hole (41) and second blasting hole (42) are respectively set at both ends of the drilling site in the pressure relief tunnel (3) to form a fan shape. Step B4: Repeat step B2 to load explosives into one blast hole (41) and the second blast hole (42) on both sides of each drilling site to form a charging section; Step C: Excavate the decompression relief tunnel (3); Step D: Conduct intensive deep-hole pre-splitting blasting in the area where the pressure relief tunnel (3) is located, including the following specific steps: Step D1: On both sides of the pressure relief roadway (3), intensive blasting pre-splitting is carried out on the thick hard sandstone of the basic roof (300) on the coal seam (100) to ensure that the pre-splitting range of the basic roof (300) covers the area to be excavated where the first roadway (21) of the first coal roadway and the second roadway (22) of the second coal roadway are located in the rockburst coal seam (100); Step D2: After completing the blasting at the previous location, proceed with the blasting at the next location until the pre-splitting work of the overlying roof of the entire area to be excavated is completed; Step D3: Repeat step D2 until the overall weakening of the basic top (300) is achieved, wherein a crack is formed on the charging section of the first blast hole (41), the crack including radial crack (5) and circumferential crack (6) so that adjacent first blast holes (41) are interconnected; a crack is formed on the charging section of the second blast hole (42), the crack including radial crack (5) and circumferential crack (6) so that adjacent second blast holes (42) are interconnected to avoid creating a blasting pre-splitting blind zone; Step E: Excavate the coal seam roadway within the pre-splitting blasting coverage area of ​​the pressure relief measures roadway (3), including the following specific steps: Excavate in the low stress zone within the pre-splitting coverage area of ​​the basic roof (300), excavate the coal seam roadway, and make the excavation face as low stress zone as possible to avoid stress concentration causing an increase in impact risk; During the tunneling and use of the coal seam roadway, it is within the coverage area of ​​the overlying basic roof blasting and pre-splitting.

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