A method for preventing and controlling rock burst disasters in large tunnels

Abstract

The present invention provides a method for preventing and controlling rock burst disasters in large tunnels, and relates to the technical field of preventing and controlling rock burst disasters. The method for preventing and controlling rock burst disasters in large tunnels sets buffer zones on the roof between the working face and the large tunnel area, and on the roof of the large tunnel area. The method sets multi-level buffer zones in different regions from the working face to the large tunnel area, based on the layout of the mining space around the large tunnel. This blocks the transmission of rock burst from the working face roof to the large tunnel area roof, and also blocks the transmission of roof pressure changes caused by the advancement of the working face to the roof of the large tunnel area. It can also resist the pressure from the roof portion of the large tunnel area located above the buffer zone. Therefore, the method can block the pressure from the working face roof and the portion of the large tunnel area roof above the buffer zone, greatly weakening rock burst and mining impact, forming a relatively comprehensive protection for the large tunnel, and effectively preventing the occurrence of rock burst disasters in the large tunnel.

Description

Technical Field

[0001] The present invention relates to the technical field of prevention and control of rock burst disasters, and in particular to a method for preventing and control rock burst disasters in a large tunnel. Background Art

[0002] A main tunnel is a passage excavated during underground mining for hoisting, transportation, ventilation, drainage, and power supply. Within the mining area, the roof of the main tunnel is subject to rock bursts and the impact of the advancing working face, posing a potential safety hazard of collapse. However, there is currently no method for preventing and controlling rock bursts specifically in main tunnels, and conventional methods for preventing and controlling rock bursts in roadways are not suitable for this purpose. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for preventing and controlling rock burst disasters in large tunnels, so as to solve the technical problem in the prior art that large tunnels have the potential safety hazard of roof collapse.

[0004] The method for preventing and controlling rock burst disasters in large tunnels provided by the present invention provides buffer zones on the roof between the working face and the large tunnel area and on the roof of the large tunnel area, respectively. The large tunnel area includes the large tunnel and the inter-tunnel protective coal pillars between adjacent large tunnels.

[0005] The method for preventing and controlling rock burst disasters in large tunnels provided by the present invention can produce the following beneficial effects:

[0006] The method for preventing and controlling rock burst disasters in large tunnels provided by the present invention is based on the layout of the mining space around the large tunnel, and multi-level buffer zones are set up in different areas from the working face to the large tunnel area. Among them, a buffer zone is set on the roof between the working face and the large tunnel area to block the transmission of rock burst from the working face roof to the large tunnel area roof, and also blocks the transmission of roof pressure changes caused by the advancement of the working face to the roof of the large tunnel area, greatly weakening the impact of mining; and a buffer zone is set on the roof of the large tunnel area, which can resist the pressure from the roof part of the large tunnel area above the buffer zone, and further block the pressure from the side of the protective coal pillar of the large tunnel. Therefore, the method for preventing and controlling rock burst disasters in large tunnels provided by the present invention can block the pressure from the working face roof and the part of the roof above the buffer zone in the large tunnel area, greatly weakening the rock burst and mining impact, forming a relatively comprehensive protection for the large tunnel, and effectively preventing the occurrence of rock burst disasters in large tunnels.

[0007] Furthermore, the buffer zone is set on the roof between the working face and the main tunnel area, including: setting a first-level buffer zone on the roof of the main tunnel protection coal pillar on the side close to the working face, and / or setting a second-level buffer zone on the roof of the main tunnel protection coal pillar on the side close to the main tunnel area, wherein the main tunnel protection coal pillar is set between the working face and the main tunnel area.

[0008] Under this technical solution, the first-level buffer zone plays a role in blocking the transmission of impact ground pressure from the working face and mining pressure to the main tunnel area, and the second-level buffer zone plays a role in blocking the transmission of pressure from the main tunnel protective coal pillar roof to the main tunnel area, and can further block the transmission of impact ground pressure from the working face and mining pressure to the main tunnel area. The blocking effect is further enhanced, and the preventive effect on impact ground pressure disasters in the main tunnel area is also further enhanced.

[0009] Furthermore, the step of setting a first-level buffer zone on the roof of the main tunnel protective coal pillar on the side close to the working face includes: constructing a first drilling group on the roof of the excavation retreat channel between the working face and the main tunnel protective coal pillar, which is upward and inclined toward the main tunnel protective coal pillar, and the bottoms of the holes drilled by the first drilling group are all located above the main tunnel protective coal pillar; fracturing is performed in the holes drilled by the first drilling group to form the first-level buffer zone;

[0010] The step of setting a second-level buffer zone on the roof of the main tunnel protection coal pillar on the side close to the main tunnel area includes: constructing a second drilling group on the roof of the main tunnel close to the main tunnel protection coal pillar, which is upward and inclined toward the main tunnel protection coal pillar, and making the bottoms of the drill holes of the second drilling group all located above the main tunnel protection coal pillar; and performing fracturing in the drill holes of the second drilling group to form the second-level buffer zone.

[0011] Under this technical solution, the fissures formed in the drill holes of the first drilling group are located above the protective coal pillars of the main tunnel, which can block the pressure from the working face from being transmitted to the main tunnel area. At the same time, the protective coal pillars of the main tunnel can also support the broken roof on the working face side, thereby improving the overall stability of the roof.

[0012] The cracks formed by fracturing in the drill holes of the second drilling group are also located above the protective coal pillar of the main tunnel, which can block the pressure from one side of the protective coal pillar of the main tunnel from being transmitted to the main tunnel area. At the same time, the protective coal pillar of the main tunnel can also support the broken roof on one side of the main tunnel area, thereby improving the overall stability of the roof.

[0013] Furthermore, when constructing the boreholes of the first drilling group, the boreholes of the first drilling group are evenly arranged along the direction of the excavation retreat channel, and the borehole spacing is such that the cracks formed by fracturing in adjacent boreholes are interconnected;

[0014] When constructing each borehole of the second drilling group, the boreholes of the second drilling group are evenly arranged along the direction of the main tunnel close to the main tunnel protection coal pillar, and the drilling hole spacing can enable the cracks formed by fracturing in adjacent boreholes to penetrate each other.

[0015] Under this technical solution, the cracks in the first-level buffer zone are interconnected, and the cracks in the second-level buffer zone are interconnected, both of which can ensure the blocking effect on the incoming pressure.

[0016] Furthermore, the fracturing method implemented in the boreholes of the first borehole group is blasting fracturing, and / or the fracturing method implemented in the boreholes of the second borehole group is blasting fracturing.

[0017] Under this technical solution, the fracturing intensity of blasting is high, which can easily cause the rock formation to break in the target area, thereby ensuring the pressure blocking effect of the buffer zone.

[0018] Furthermore, the step of setting a buffer zone on the roof of the main tunnel area includes: constructing a third drilling group on the roof of the main tunnel of the mining area track, the drilled holes of the third drilling group all include connected inclined sections and horizontal sections, and each of the horizontal sections is located above the main tunnel area; fracturing is performed in each of the horizontal sections to form a third-level buffer zone.

[0019] Under this technical solution, the third-level buffer zone acts to resist pressure from the overlying rock strata in the main tunnel, further preventing the transmission of pressure from the overlying rock strata above the main tunnel's protective coal pillars to the main tunnel area. Furthermore, compared to drilling holes in the first and second-level buffer zones, drilling holes in both inclined and horizontal sections simplifies the construction process.

[0020] Furthermore, the main tunnel area includes N main tunnels and (N-1) the inter-tunnel protection coal pillars, and the drilling holes of the third drilling group are constructed on the roofs of each of the inter-tunnel protection coal pillars close to both sides of the main tunnel and on the roofs of the (N-2) main tunnels located in the middle, and the horizontal sections above the inter-tunnel protection coal pillars are extended along the direction of the corresponding inter-tunnel protection coal pillars, and the horizontal sections above the main tunnels are extended along the direction of the corresponding main tunnel; wherein N is a natural number greater than or equal to 2.

[0021] Under this technical solution, the drill hole extends along the direction of the inter-tunnel protective coal pillar or along the direction of the corresponding large tunnel, and the extension direction is relatively regular, which is conducive to ensuring the drilling space spacing, and then conducive to implementing uniform fracturing to ensure the fracturing effect.

[0022] Furthermore, the fracturing method implemented in each of the horizontal sections is hydraulic fracturing.

[0023] Under this technical solution, hydraulic fracturing can achieve segmented fracturing, thereby enabling fracturing to be carried out at multiple fracturing points in the horizontal section.

[0024] Furthermore, the buffer zones are all provided on the key layers of the top plate, and the cracking points are all located above the middle of the key layers.

[0025] Under this technical solution, the rock layer below the buffer zone is of moderate thickness and the surrounding rock is highly stable, which ensures that the buffer zone can effectively block pressure transmission.

[0026] Furthermore, the key layer is the basic top of the top plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0028] Figure 1 A schematic top view of the construction of a method for preventing and controlling rock burst disasters in a large tunnel according to an embodiment of the present invention;

[0029] Figure 2 A side view construction diagram of a method for preventing and controlling rock burst disasters in a large tunnel provided by an embodiment of the present invention.

[0030] Description of reference numerals:

[0031] 110-return air tunnel in mining area; 120-track tunnel in mining area; 130-transport tunnel in mining area;

[0032] 200-main tunnel protection coal pillar;

[0033] 310- transport chute; 320- return air chute;

[0034] 400-excavation retreat channel;

[0035] 500-working surface;

[0036] 600- goaf;

[0037] 710-first level buffer zone; 720-second level buffer zone; 730-third level buffer zone;

[0038] 810 - first drilling group; 820 - second drilling group; 830 - third drilling group; 840 - fissure;

[0039] 910-direct top; 920-basic top. DETAILED DESCRIPTION

[0040] In order to make the above-mentioned objects, features and advantages of the present invention more clearly understood, the following detailed description of the specific embodiments of the present invention is given in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0041] This embodiment provides a method for preventing and controlling rock burst disasters in a large tunnel. Figure 1 and Figure 2 As shown in the construction diagram of the method, buffer zones are set on the roof between the working face 500 and the main tunnel area and on the roof of the main tunnel area, wherein the main tunnel area includes the main tunnel and the inter-tunnel protection coal pillars between adjacent main tunnels.

[0042] The method for preventing and controlling rock burst disasters in large tunnels provided in this embodiment is based on the layout of the mining space around the large tunnel. From the working face 500 to the large tunnel area, multi-level buffer zones are set up in different areas to block and relieve pressure. Among them, a buffer zone is set on the roof between the working face 500 and the large tunnel area to block the transmission of rock burst from the roof of the working face 500 to the roof of the large tunnel area. At the same time, it also blocks the transmission of roof pressure changes caused by the advancement of the working face 500 to the roof of the large tunnel area, greatly weakening the impact of mining; and a buffer zone is set on the roof of the large tunnel area, which can resist the pressure from the roof part of the large tunnel area above the buffer zone, and further block the pressure from the side of the large tunnel protective coal pillar 200. Therefore, the method for preventing and controlling rock burst disasters in large tunnels provided in this embodiment can block the pressure from the roof of the working face 500 and the part above the buffer zone of the roof of the large tunnel area, greatly weakening the rock burst and mining impact, forming a relatively comprehensive protection for the large tunnel, and effectively preventing the occurrence of rock burst disasters in large tunnels.

[0043] Specifically, in this embodiment, the main tunnel area includes the mining area return air main tunnel 110, the mining area rail main tunnel 120, the mining area transport main tunnel 130, and two inter-tunnel protective coal pillars, and the mining area rail main tunnel 120 is located between the mining area return air main tunnel 110 and the mining area transport main tunnel 130. The mining area return air main tunnel 110 is far away from the working face 500, and the mining area transport main tunnel 130 is close to the working face 500. Of course, in other embodiments of the present application, the number of main tunnels is not limited to the above three, and the arrangement of the main tunnels is not limited to the above arrangement, but none of these affects the implementation of the method provided in this application.

[0044] Specifically, in this embodiment, Figure 1 and Figure 2As shown, a buffer zone is provided in the roof between the working face 500 and the main tunnel area, including: a first-level buffer zone 710 provided in the roof on the side of the main tunnel protection coal pillar 200 near the working face 500, and a second-level buffer zone 720 provided in the roof on the side of the main tunnel protection coal pillar 200 near the main tunnel area. The main tunnel protection coal pillar 200 is provided between the working face 500 and the main tunnel area. With this arrangement, the first-level buffer zone 710 serves to block the transmission of rock burst pressure and mining pressure from the working face 500 to the main tunnel area, while the second-level buffer zone 720 serves to block the transmission of pressure from the roof of the main tunnel protection coal pillar 200 to the main tunnel area. This can further block the transmission of rock burst pressure and mining pressure from the working face 500 to the main tunnel area, further enhancing the blocking effect and the prevention of rock burst disasters in the main tunnel area.

[0045] It should be noted that in other embodiments of the present application, when the safety hazard of rock burst disaster in the main tunnel is relatively small, only the first-level buffer zone 710 or only the second-level buffer zone 720 can be set, as long as it can block the pressure from one side of the working face 500.

[0046] More specifically, in this embodiment, Figure 2 As shown, the steps of setting a first-level buffer zone 710 on the roof of the main tunnel protective coal pillar 200 near the working face 500 include: constructing a first drilling group 810 in the roof of the excavation retreat channel 400 between the working face 500 and the main tunnel protective coal pillar 200, which is upward and inclined toward the main tunnel protective coal pillar 200, so that the bottoms of the holes drilled in the first drilling group 810 are all located above the main tunnel protective coal pillar 200; and fracturing the holes drilled in the first drilling group 810 to form the first-level buffer zone 710. With this arrangement, the fissures 840 formed by the fracturing in the holes drilled in the first drilling group 810 are located above the main tunnel protective coal pillar 200, which can block the pressure from the working face 500 from being transmitted to the main tunnel area. At the same time, the main tunnel protective coal pillar 200 can also support the fractured roof on the working face 500 side, thereby improving the overall stability of the roof.

[0047] Specifically, in this embodiment, along the direction of the transport chute 310 or the return air chute 320, the tunneling and withdrawal passage 400 and the working face 500 are located on either side of the coal to be mined, with the goaf 600 located behind the working face 500. Before setting up the first-level buffer zone 710, the size of the main tunnel protective coal pillar 200 must be determined based on a comprehensive assessment of the coal seam occurrence conditions, the stress conditions in the main tunnel, and the risk of rock burst. The location of the tunneling and withdrawal passage 400 is determined based on the size of the main tunnel protective coal pillar 200, and the tunneling and withdrawal passage 400 is deployed in advance when the working face 500 is a safe distance away from the tunneling and withdrawal passage 400.

[0048] More specifically, in this embodiment, Figure 2 As shown, the steps of setting a second-level buffer zone 720 in the roof of the main tunnel protection coal pillar 200 near the main tunnel area include: constructing a second set of drill holes 820 in the roof of the main tunnel near the main tunnel protection coal pillar 200, which is upward and inclined toward the main tunnel protection coal pillar 200, so that the bottoms of the holes in the second set of drill holes 820 are all located above the main tunnel protection coal pillar 200; and fracturing the holes in the second set of drill holes 820 to form the second-level buffer zone 720. With this arrangement, the fissures 840 formed by the fracturing in the holes of the second set of drill holes 820 are also located above the main tunnel protection coal pillar 200, which can block the pressure from the main tunnel protection coal pillar 200 from being transmitted to the main tunnel area. At the same time, the main tunnel protection coal pillar 200 can also support the fractured roof on the main tunnel area side, thereby improving the overall stability of the roof.

[0049] More specifically, in this embodiment, the main tunnel close to the main tunnel protection coal pillar 200 is the mining area transportation main tunnel 130, so in this embodiment, the second drilling group 820 is constructed in the mining area transportation main tunnel 130.

[0050] Specifically, in this embodiment, when constructing the boreholes of the first drilling group 810, the boreholes of the first drilling group 810 are evenly arranged along the direction of the excavation retreat channel 400, and the borehole spacing is such that the fissures 840 formed by fracturing in adjacent boreholes are interconnected. When constructing the boreholes of the second drilling group 820, the boreholes of the second drilling group 820 are evenly arranged along the direction of the main tunnel near the main tunnel protection coal pillar 200, and the borehole spacing is such that the fissures 840 formed by fracturing in adjacent boreholes are interconnected. Under this arrangement, the fissures 840 in the first-level buffer zone 710 are interconnected, and the fissures 840 in the second-level buffer zone 720 are interconnected, both of which can ensure the blocking effect of incoming pressure.

[0051] Specifically, in this embodiment, explosive fracturing is used in the boreholes of the first drilling group 810, and explosive fracturing is used in the boreholes of the second drilling group 820. Explosive fracturing has a high fracturing intensity and easily fractures the rock formation in the target area, thereby ensuring the pressure-blocking effect of the buffer zone.

[0052] It should be noted that in other embodiments of the present application, the fracturing method is not limited to explosive fracturing, and other high-intensity fracturing methods can also be used, as long as the target rock formation can achieve the desired degree of fracture in the target area. Of course, the fracturing methods used to form the first-level buffer zone 710 and the second-level buffer zone 720 can also be different.

[0053] Specifically, in this embodiment, the steps for establishing a buffer zone in the main tunnel area's roof include: constructing a third drilling group 830 in the roof of the mining area's track main tunnel 120. Each drilled hole in this third drilling group 830 includes a connected inclined section and a horizontal section, with each horizontal section positioned above the main tunnel area; and fracturing each horizontal section to form a third-level buffer zone 730. With this arrangement, the third-level buffer zone 730 acts to resist pressure from the overlying strata of the main tunnel, while further blocking the transmission of pressure from the overlying strata of the main tunnel's protective coal pillar 200 to the main tunnel area. Furthermore, compared to drilling the first-level buffer zone 710 and the second-level buffer zone 720, drilling holes that include both inclined and horizontal sections simplifies the construction process.

[0054] It should be noted here that in other embodiments of the present application, the drilling implementation methods of the first-level buffer zone 710 and the second-level buffer zone 720 may also be referred to, as long as fracturing can be implemented above the protective coal pillars between the tunnels and above the large tunnels located in the middle position.

[0055] More specifically, in this embodiment, the spacing of the horizontal segments allows adjacent fissures 840 to be interconnected. This arrangement allows for uniform fracturing of the overburden strata, resulting in a better effect in blocking incoming pressure.

[0056] Specifically, in this embodiment, the third drilling group 830 is drilled in the roofs of the two sides of each inter-lane protective coal pillar near the main lane, as well as in the roofs of the (N-2) main lanes located in the middle. The horizontal sections above the inter-lane protective coal pillars extend along the direction of the corresponding inter-lane protective coal pillars, and the horizontal sections above the main lanes extend along the direction of the corresponding main lanes. N is a natural number greater than or equal to 2. With this arrangement, the drill holes extend along the direction of the inter-lane protective coal pillars or the direction of the corresponding main lanes, and the extension direction is relatively regular, which helps ensure the drilling spacing and, in turn, facilitates uniform fracturing to ensure a good fracturing effect.

[0057] It should be noted that, in this embodiment, N is 3, but in other embodiments of the present application, N may also be 4, etc.

[0058] Specifically, in this embodiment, the fracturing method implemented in each horizontal segment is hydraulic fracturing. Hydraulic fracturing can achieve staged fracturing, thereby enabling fracturing to be implemented at multiple fracturing points in the horizontal segment.

[0059] Specifically, in this embodiment, the buffer zones are all located in the critical layer of the roof, and the fracture points are all located above the middle of the critical layer. This arrangement ensures that the rock layer below the buffer zone is of moderate thickness, the surrounding rock is highly stable, and the buffer zone can effectively block pressure transmission.

[0060] Specifically, in this embodiment, the key layer is the basic top 920 of the top plate, which is located above the direct top 910 .

[0061] Finally, it should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include," "comprise," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0062] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to the embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is to be construed in the widest manner consistent with the principles and novel features disclosed herein.

Claims

1. A method for preventing and controlling rock burst disasters in a large tunnel, characterized in that: Buffer zones are respectively provided on the roof between the working face (500) and the main tunnel area, and on the roof of the main tunnel area, wherein the main tunnel area includes the main tunnel and the inter-tunnel protective coal pillars between adjacent main tunnels; The buffer zone is provided on the roof between the working face (500) and the main tunnel area, comprising: A first-level buffer zone (710) is provided on the roof of a large tunnel protection coal pillar (200) on a side close to the working face (500), and / or a second-level buffer zone (720) is provided on the roof of a large tunnel protection coal pillar (200) on a side close to the large tunnel area, wherein the large tunnel protection coal pillar (200) is provided between the working face (500) and the large tunnel area; The step of providing a first-level buffer zone (710) on the roof of the main tunnel protective coal pillar (200) on the side close to the working face (500) comprises: constructing a first drilling group (810) on the roof of the excavation retreat channel (400) between the working face (500) and the main tunnel protective coal pillar (200) and tilting it upward and toward the main tunnel protective coal pillar (200), and making the bottoms of the holes drilled in the first drilling group (810) all located above the main tunnel protective coal pillar (200); and performing fracturing in the holes drilled in the first drilling group (810) to form the first-level buffer zone (710); The step of setting a second-level buffer zone (720) on the roof of the main tunnel protection coal pillar (200) on one side close to the main tunnel area includes: constructing a second drilling group (820) on the roof of the main tunnel close to the main tunnel protection coal pillar (200) and tilting upward and toward the main tunnel protection coal pillar (200), and making the bottoms of the holes of the second drilling group (820) all located above the main tunnel protection coal pillar (200); and performing fracturing in the holes of the second drilling group (820) to form the second-level buffer zone (720).

2. The method for preventing and controlling rock burst disasters in large tunnels according to claim 1, characterized in that: When constructing the boreholes of the first drilling group (810), the boreholes of the first drilling group (810) are evenly arranged along the direction of the excavation retreat channel (400), and the borehole spacing is such that the fissures (840) formed by the fracturing in adjacent boreholes can be interconnected; When constructing each borehole of the second borehole group (820), each borehole of the second borehole group (820) is evenly arranged along the direction of the main tunnel close to the main tunnel protection coal pillar (200), and the borehole spacing is such that the cracks (840) formed by fracturing in adjacent boreholes can be interconnected.

3. The method for preventing and controlling rock burst disasters in a large tunnel according to claim 1, characterized in that: The fracturing method implemented in the boreholes of the first borehole group (810) is blasting fracturing, and / or the fracturing method implemented in the boreholes of the second borehole group (820) is blasting fracturing.

4. The method for preventing and controlling rock burst disasters in large tunnels according to claim 1, characterized in that: The steps for setting a buffer zone on the roof of the main tunnel area include: A third drilling group (830) is constructed on the roof of the main track tunnel (120) in the mining area, wherein the drilled holes of the third drilling group (830) each include a connected inclined section and a horizontal section, and each of the horizontal sections is located above the main track area; Fracturing is performed on each of the horizontal segments to form a third-level buffer zone (730).

5. The method for preventing and controlling rock burst disasters in large tunnels according to claim 4, characterized in that: The large tunnel area includes N large tunnels and (N-1) said inter-tunnel protection coal pillars, and the drilling holes of the third drilling group (830) are constructed on the roofs of each of the inter-tunnel protection coal pillars close to both sides of the large tunnel and on the roofs of the (N-2) large tunnels located in the middle, and the horizontal sections above the inter-tunnel protection coal pillars are extended along the direction of the corresponding inter-tunnel protection coal pillars, and the horizontal sections above the large tunnels are extended along the direction of the corresponding large tunnel; wherein N is a natural number greater than or equal to 2.

6. The method for preventing and controlling rock burst disasters in large tunnels according to claim 4, characterized in that: The fracturing method implemented in each horizontal section is hydraulic fracturing.

7. The method for preventing and controlling rock burst disasters in large tunnels according to claim 4, characterized in that: The buffer zones are all arranged on the key layers of the top plate, and the cracking points are all located in the area above the middle of the key layers.

8. The method for preventing and controlling rock burst disasters in large tunnels according to claim 7, characterized in that: The key layer is the basic top (920) of the top plate.

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