Method for preventing and controlling rock bursts

Abstract

The method for preventing and controlling rock bursts of the present invention comprises the following steps: Step S1, dividing the roof rock stratum with a thickness greater than or equal to a first preset value and a compressive strength greater than or equal to a second preset value above at least one of the roadway to be treated and the working face to be mined into the main rock stratum causing rock bursts; Step S2, drilling holes in the main rock stratum causing rock bursts; Step S3, using the holes to perform hydraulic fracturing on the main rock stratum causing rock bursts so as to form a hydraulic fracture zone with hydraulic fracturing cracks in the main rock stratum causing rock bursts; Step S4, opening a plurality of prevention and control caves communicating with the hydraulic fracturing cracks in the hydraulic fracture zone of the main rock stratum causing rock bursts. The method for preventing and controlling rock bursts of the present invention can reduce the risk of rock bursts occurring in the working face.

Description

Technical Field

[0001] The present invention relates to the technical field of mining, and in particular to a method for preventing and controlling rock bursts. Background Art

[0002] In related technologies, a rock burst refers to a dynamic phenomenon in which the rock mass around a roadway or a working face suddenly and violently fails due to the instantaneous release of elastic deformation energy, often accompanied by phenomena such as the ejection of coal and rock masses, loud noises, and air waves. Rock burst accidents are characterized by a large degree of damage and are the focus of roof disaster prevention and control. Rock bursts mostly occur in the roof, especially in coal seams with thick and hard roofs. In the prevention and control of rock bursts, large-diameter boreholes in the coal seam are often used. By drilling large-diameter boreholes in the coal seam, stress relief holes are formed to reduce and slow down the stress concentration in the coal body. This method can relieve the high-stress state of the coal body to a certain extent and weaken the impact risk. However, the pressure relief by large-diameter boreholes in the coal seam is a local danger-removing measure for rock bursts and is difficult to improve the regional stress environment. Under high-stress conditions, the pressure relief effect is limited. A large number of boreholes may damage the integrity of the surrounding rock of the roadway, have an adverse impact on the stability of the surrounding rock of the roadway. The borehole workload is large, interfering with normal production and having low efficiency. Large-diameter boreholes may also cause accidents such as coal and gas outbursts, increasing the safety risk. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems in the related technologies to some extent. For this purpose, an embodiment of the present invention provides a method for preventing and controlling rock bursts.

[0004] The method for preventing and controlling rock bursts according to the embodiment of the present invention includes the following steps:

[0005] Step S1: Divide the roof rock layer with a thickness greater than or equal to a first preset value and a compressive strength greater than or equal to a second preset value above at least one of the roadway to be treated and the working face to be mined into the main rock layers causing rock bursts;

[0006] Step S2: Drill boreholes in the main rock layers causing rock bursts;

[0007] Step S3: Use the boreholes to hydraulically fracture the main rock layers causing rock bursts so as to form a hydraulic fracture zone with hydraulic fractures in the main rock layers causing rock bursts;

[0008] Step S4: Open a plurality of prevention and control caves communicating with the hydraulic fractures in the hydraulic fracture zone of the main rock layers causing rock bursts.

[0009] In some embodiments, in step S4, cut the rock outward from the boreholes located in the hydraulic fracture zone to open a plurality of the prevention and control caves.

[0010] In some embodiments, the prevention and control cavities include a first prevention and control cavity;

[0011] In step S4, a position in one of the boreholes located in the hydraulic fracture zone is used as the central position of the first prevention and control cavity, and then the rock is cut outward to form the first prevention and control cavity.

[0012] In some embodiments, in step S4, a plurality of the first prevention and control cavities are provided in the hydraulic fracture zone and are distributed along the extension direction of the borehole.

[0013] In some embodiments, in step S4, the distance between two adjacent first prevention and control cavities in the extension direction of the same borehole is greater than or equal to 10 meters.

[0014] In some embodiments, after the borehole is hydraulically fractured, the rock is cut outward from a plurality of positions in the borehole in sequence along the direction away from the bottom of the borehole to form a plurality of the prevention and control cavities.

[0015] In some embodiments, the borehole is divided into a plurality of sub-boreholes along the extension direction of the borehole, and hydraulic fracturing is performed on the plurality of sub-boreholes in sequence along the direction away from the bottom of the borehole. After hydraulic fracturing is completed for one of the two adjacent sub-boreholes adjacent to the bottom of the borehole, the rock is cut outward from the one of the two adjacent sub-boreholes adjacent to the bottom of the borehole to form the prevention and control cavity, and then hydraulic fracturing is performed on the one of the two adjacent sub-boreholes away from the bottom of the borehole.

[0016] In some embodiments, the diameter of the prevention and control cavity is greater than or equal to 1 meter;

[0017] In step S2, there are a plurality of the boreholes, and the plurality of boreholes are arranged at intervals;

[0018] In step S4, a hydraulic jet is sent to the borehole located in the hydraulic fracture zone by a drilling rig, and the hydraulic jet jets jet water with a pressure greater than or equal to a third preset value on the rock in the hydraulic fracture zone to cut the rock.

[0019] In some embodiments, in step S1, the roof rock formation with a thickness greater than or equal to a first preset value and a compressive strength greater than or equal to a second preset value above at least one of the roadway to be treated and the working face to be mined is divided into multiple main strata causing rock burst disasters;

[0020] In the step S2, the boreholes are drilled upward from the formed roadway. The extending direction of the boreholes in the horizontal direction and the extending direction of the roadway to be treated are both the first direction, and a plurality of the boreholes are arranged at intervals in the second direction. Any two of the first direction, the second direction, and the vertical direction are perpendicular to each other;

[0021] In the step S4, the top of the anti-collapse cave is located at the top of the main control rock stratum causing rock burst where it is located, and the bottom of the anti-collapse cave is located at the bottom of the main control rock stratum causing rock burst where it is located;

[0022] In the step S4, the pressure of the jet water is greater than or equal to 50 MPa.

[0023] The method for preventing and controlling rock burst according to the embodiment of the present invention further includes a step S5. In the step S5, after a plurality of the anti-collapse caves are opened, the working face to be mined is mined. Based on the microseismic monitoring during the mining process, the prevention and control effect of rock burst is evaluated. The prevention and control effect of rock burst can be improved by at least one of increasing the number of the boreholes, increasing the number of the anti-collapse caves, shortening the distance between two adjacent anti-collapse caves, and increasing the hydraulic fracturing displacement.

[0024] The beneficial effects of the present invention are as follows: The method for preventing and controlling rock burst according to the embodiment of the present invention drills boreholes in the main control rock stratum causing rock burst and performs hydraulic fracturing so as to fully fracture the deep rock mass in the main control rock stratum causing rock burst, destroy its integrity and strength, and promote the main control rock stratum causing rock burst to fracture along the cracks and collapse in time during the coal mining period. And after the hydraulic fracturing, by opening anti-collapse caves in the main control rock stratum causing rock burst, large-sized cavity holes can be formed in the main control rock stratum causing rock burst, so that the stress is redistributed, the high-stress pressure relief effect is exerted, the rock mass is caused to have a dislocation displacement, and the accumulated energy of the rock mass is effectively released. By using the combined action of the hydraulic fracturing cracks and the anti-collapse caves, the hard and complete main control rock stratum causing rock burst is transformed into a relatively fractured roof containing a large number of cavity holes. The transformed main control rock stratum causing rock burst is not likely to generate large-energy breaking events and is difficult to induce strong dynamic load disturbances, and can be used as a buffer cushion to absorb the impact energy generated by other rock strata, thereby reducing the risk of rock burst occurrence in the working face. Description of the Drawings

[0025] Figure 1 is a schematic diagram of opening an anti-collapse cave by the method for preventing and controlling rock burst according to the embodiment of the present invention.

[0026] Figure 2 is a schematic diagram of a jet tool string according to the embodiment of the present invention.

[0027] Reference numerals: 1, main control rock stratum causing rock burst; 2, borehole; 3, hydraulic fracturing crack; 4, first prevention cave; 5, safety handrail; 6, hydraulic jet; 7, centralizer; 8, ball seat; 9, push rod. Detailed implementation manners

[0028] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention, and should not be construed as a limitation to the present invention.

[0029] The method for preventing and controlling rock burst according to the embodiment of the present invention will be described below with reference to the accompanying drawings. As Figure 1 and Figure 2 shown, the method for preventing and controlling rock burst according to the embodiment of the present invention includes the following steps:

[0030] Step S1: Divide the roof rock stratum with a thickness greater than or equal to a first preset value and a compressive strength greater than or equal to a second preset value above at least one of the roadway to be treated and the working face to be mined into the main control rock stratum 1 causing rock burst. Specifically, analyze the occurrence parameters of the hard roof rock stratum according to the roof rock stratum histogram. Take cores from the roof rock stratum and conduct rock physical and mechanical experiments to evaluate its rock burst tendency. Microseismic monitoring is a technology used to detect and analyze minute seismic activities caused by rock fractures or stress changes. Through microseismic monitoring, the changes in the underground structure can be understood in real time, the stability of the rock stratum can be evaluated, and potential geological disasters can be predicted. Use microseismic monitoring technology to monitor the seismic wave characteristics after the roof rock mass fractures, analyze the distribution positions and sizes of microseismic events, and combine the occurrence parameters of the roof rock stratum, the rock burst tendency of the rock stratum, and the distribution of microseismic events to comprehensively judge whether the roof rock stratum is the main control rock stratum 1 causing rock burst, and prevent and control rock burst for the main control rock stratum 1 causing rock burst. For example, divide the roof rock stratum with a thickness greater than or equal to a first preset value and a compressive strength greater than or equal to a second preset value above the roadway to be treated and the working face to be mined into the main control rock stratum 1 causing rock burst.

[0031] Step S2: Open boreholes 2 in the main control rock stratum 1 causing rock burst. Specifically, in step S2, there are multiple boreholes 2, and the multiple boreholes 2 are arranged at intervals, so as to facilitate hydraulic fracturing of multiple positions of the main control rock stratum 1 causing rock burst in the horizontal direction, so as to increase the range of hydraulic fracturing cracks 3.

[0032] In some embodiments, in step S2, boreholes 2 are opened upward from the formed roadway. The extension direction of the boreholes 2 in the horizontal direction and the extension direction of the roadway to be treated are both the first direction, and the multiple boreholes 2 are arranged at intervals in the second direction. Any two of the first direction, the second direction, and the up-down direction are perpendicular to each other. For example, the first direction is consistent with the coal seam strike, and the extension direction of the boreholes 2 in the horizontal direction and the extension direction of the roadway to be treated are both the coal seam strike.

[0033] For example, a drilling site is arranged in the formed tunnel, and a thousand-meter directional drilling is used in the coal mine to open a borehole 2 in the main rock layer 1 that causes rock burst disasters. After the borehole 2 climbs to the main rock layer 1 that causes rock burst disasters, it turns to the horizontal plane. That is, the borehole 2 includes a climbing section and a horizontal section. The top of the climbing section is connected to the horizontal section, and the extension direction of the horizontal section is consistent with the extension direction of the tunnel to be treated. The size of the horizontal section in the first direction is greater than or equal to 300 meters and less than or equal to 1000 meters.

[0034] In some embodiments, the distance between two adjacent boreholes 2 in the second direction is greater than or equal to 30 meters and less than or equal to 50 meters, so that after hydraulic fracturing, the hydraulic fracturing cracks 3 can be distributed in the second direction in the area between two adjacent boreholes 2 in the rock formation 1 that controls rock burst disasters. For example, the distance between two adjacent boreholes 2 in the second direction is 40 meters.

[0035] Step S3, hydraulically fracturing the main rock formation 1 causing rock burst disaster by using the borehole 2, so as to form a hydraulic fracture zone with hydraulic fracture cracks 3 in the main rock formation 1 causing rock burst disaster. Specifically, hydraulically fracturing the main rock formation 1 causing rock burst disaster is performed, so that the main rock formation 1 causing rock burst disaster is cut off by the hydraulic fracture cracks 3, so as to fully fracture the main rock formation 1 causing rock burst disaster, destroy its integrity and strength, and thus relieve the pressure. For example, a directional drilling rig is used to send an expandable open hole packer into a specified position of the borehole 2, and a double-seal single-card staged fracturing process is adopted. Start the downhole hydraulic fracturing pump group to inject water into the isolation section for fracturing, and form large-area fractures in the main rock formation 1 causing rock burst disaster. After the fracturing is completed, the expandable open hole packer is depressurized and unsealed, and then the next staged fracturing operation is carried out.

[0036] Step S4, multiple prevention and control caves connected to the hydraulic fracture cracks 3 are opened in the hydraulic fracture area of ​​the main rock formation 1 causing rock burst disaster. That is to say, after the hydraulic fracture of the main rock formation 1 causing rock burst disaster is relieved, multiple holes are opened in the area (hydraulic fracture area) with hydraulic fracture cracks 3 in the main rock formation 1 causing rock burst disaster, so as to serve as prevention and control caves. Specifically, the diameter of the prevention and control cave is greater than or equal to 1 meter. For example, the diameter of the prevention and control cave is 2 meters, 3 meters, 5 meters, 8 meters or 10 meters.

[0037] According to the method for preventing and controlling rock bursts in embodiments of the present invention, boreholes 2 are drilled in the main rock stratum 1 causing rock bursts and hydraulic fracturing is carried out to fully fracture the deep rock mass in the main rock stratum 1 causing rock bursts, destroy its integrity and strength, and prompt the main rock stratum 1 causing rock bursts to fracture along the cracks and collapse in time during mining. And after hydraulic fracturing, by opening prevention and control cavities in the main rock stratum 1 causing rock bursts, large-sized cavity-forming voids (free spaces) can be formed in the main rock stratum 1 causing rock bursts, enabling stress redistribution, playing a role in high-stress pressure relief, prompting the rock mass to undergo dislocation displacement, and effectively releasing the accumulated energy of the rock mass. By utilizing the combined action of the hydraulic fracturing cracks 3 and the prevention and control cavities, the hard and intact main rock stratum 1 causing rock bursts is transformed into a relatively fragmented roof containing a large number of voids. The transformed main rock stratum 1 causing rock bursts is not prone to large-energy fracture events and is difficult to induce strong dynamic load disturbances, and can absorb the impact energy generated by other rock strata as a buffer cushion layer, thereby reducing the risk of rock bursts occurring in the working face.

[0038] Therefore, the method for preventing and controlling rock bursts according to the embodiments of the present invention can reduce the risk of rock bursts occurring in the working face.

[0039] As Figure 1 and Figure 2 shown, in some embodiments, in step S4, rock is cut outward from the borehole 2 located in the hydraulic fracture zone to open a plurality of prevention and control cavities. Specifically, in step S4, a hydraulic jet 6 is sent to the borehole 2 located in the hydraulic fracture zone by a drill rig. The hydraulic jet 6 jets water flow with a pressure greater than or equal to a third preset value on the rock in the hydraulic fracture zone to cut the rock, thereby forming prevention and control cavities. Specifically, starting from the previously opened borehole 2, prevention and control cavities are opened in the hydraulic fracture zone, which can reduce the construction difficulty. The drill rig sends the hydraulic jet 6 to a designated position in the previously opened borehole 2 to cut the rock and form prevention and control cavities. For example, the drill rig includes a ball seat 8, a push rod 9, a centralizer 7, and a safety handrail 5 connected in sequence. The hydraulic jet 6 is connected to the push rod 9 to form a jet tool string, so that the drill rig drives the hydraulic jet 6 to move in the borehole 2.

[0040] In some embodiments, in step S4, the pressure of the water flow is greater than or equal to 50 MPa. For example, the pressure of the water flow is 80 MPa, 100 MPa, or 120 MPa.

[0041] As Figure 1As shown, in some embodiments, the prevention and control cavity includes a first prevention and control cavity 4. In step S4, a position (predetermined position) in one of the boreholes 2 located in the hydraulic fracture zone is used as the central position of the first prevention and control cavity 4, and then the rock is cut outward to form the first prevention and control cavity 4. Thus, the central position of the first prevention and control cavity 4 can be made to be within the corresponding borehole 2, so that multiple first prevention and control cavities 4 can be distributed along the borehole 2, and the construction difficulty can be reduced. For example, the hydraulic jet 6 is a hydraulic spray gun. The hydraulic spray gun is sent into the fracturing position of the borehole 2 by using a drill rig. The high-pressure water pump is connected to the drill pipe, the hydraulic spray gun is installed, the water pump is started, and the water pressure is gradually increased to form a high-pressure water jet. The hydraulic spray gun is moved through the drill pipe, and the abrasive water jet is used to cut the rock to form a cavity centered on the borehole 2. The backward segmented hydraulic jetting and cavity formation process is adopted, that is, the cavities are formed in segments in sequence from the direction away from the bottom of the borehole 2.

[0042] As Figure 1 As shown, in some embodiments, in step S4, a plurality of first prevention and control cavities 4 are provided in the hydraulic fracture zone and are distributed along the extension direction of the borehole 2. Specifically, in step S4, the distance between two adjacent first prevention and control cavities 4 in the extension direction of the same borehole 2 is greater than or equal to 10 meters. Arranging a plurality of first prevention and control cavities 4 in the extension direction of the borehole 2 can reduce the construction difficulty and improve the prevention and control effect of rock bursts.

[0043] In some embodiments, after the hydraulic fracturing of the borehole 2 is completed, the rock is cut outward from a plurality of positions in the borehole 2 in sequence along the direction away from the bottom of the borehole 2 to open a plurality of prevention and control cavities. That is to say, after the entire hydraulic fracturing of the borehole 2 is completed, the prevention and control cavities are opened. That is, after step S3 is completed, step S4 is carried out.

[0044] In some embodiments, the prevention and control cavity is located between two adjacent boreholes 2. So that a large-sized cavity formation cavity (free space) can exist between two adjacent boreholes 2, which is convenient for pressure relief.

[0045] In some embodiments, the borehole 2 is divided into a plurality of sub-boreholes along the extension direction of the borehole 2, and hydraulic fracturing is sequentially performed on the plurality of sub-boreholes in a direction away from the bottom of the borehole 2. After hydraulic fracturing is completed on one of the two adjacent sub-boreholes that is adjacent to the bottom of the borehole 2, the rock is cut from the inside to the outside of the one of the two adjacent sub-boreholes that is adjacent to the bottom of the borehole 2 to form a prevention and control cave, and then hydraulic fracturing is performed on the one of the two adjacent sub-boreholes that is away from the bottom of the borehole 2. That is to say, the borehole 2 is divided into multiple segments for hydraulic pressure. Along the direction away from the bottom of the borehole 2, after hydraulic fracturing is performed on one segment of the borehole 2 (each sub-borehole), a prevention and control cave is formed in the hydraulic fracture zone where the segment of the borehole 2 (the sub-borehole) is located, and then hydraulic fracturing is performed on the next segment of the borehole 2 (the next sub-borehole). Each time hydraulic fracturing is completed on one segment of the borehole 2 (a sub-borehole), a prevention and control cave is formed in the newly formed hydraulic fracture zone, thereby reducing the construction difficulty.

[0046] In step S1, the roof rock layer with a thickness greater than or equal to a first preset value and a compressive strength greater than or equal to a second preset value above at least one of the roadway to be treated and the working face to be mined is divided into multiple main strata 1 causing rock burst disasters. In step S4, the top of the prevention and control cave is located at the top of the main strata 1 causing rock burst disasters where it is located, and the bottom of the prevention and control cave is located at the bottom of the main strata 1 causing rock burst disasters where it is located. That is to say, the main strata 1 causing rock burst disasters can be multiple layers. Hydraulic fracturing is performed and prevention and control caves are formed within each layer of the main strata 1 causing rock burst disasters. The top of the prevention and control cave is adjacent to the top end of the main strata 1 causing rock burst disasters where it is located, and the bottom of the prevention and control cave is adjacent to the bottom end of the main strata 1 causing rock burst disasters where it is located, so as to increase the pressure relief effect.

[0047] The method for preventing and controlling rock burst according to the embodiment of the present invention further includes step S5. In step S5, after multiple prevention and control caves are formed, the working face to be mined is mined. Based on microseismic monitoring during the mining process, the prevention and control effect of rock burst is evaluated. The prevention and control effect of rock burst can be improved by at least one of increasing the number of boreholes 2, increasing the number of prevention and control caves, shortening the distance between two adjacent prevention and control caves, and increasing the hydraulic fracturing displacement. Specifically, based on microseismic monitoring during the mining process, the distribution and size of microseismic events of the main strata 1 causing rock burst disasters are analyzed, and compared with the working face without measures, to evaluate the prevention and control effect of rock burst. According to the feedback of the prevention and control effect, the parameters of cave formation and fracturing are corrected. The prevention and control effect of rock burst can be improved by at least one of increasing the number of boreholes 2, increasing the number of prevention and control caves, shortening the distance between two adjacent prevention and control caves, and increasing the hydraulic fracturing displacement.

[0048] According to the rock burst prevention and control method of the embodiments of the present invention, a drill rig can be used to drill holes 2 in the main controlling rock stratum 1 causing rock bursts at a long distance, and hydraulic fracturing is carried out on the main controlling rock stratum 1 causing rock bursts, so as to relieve pressure and prevent rock bursts from the high-stress source. Moreover, by using the combined action of the prevention and control caves generated by hydraulic fracturing and hydraulic jet cavitation, the hard and intact main controlling rock stratum 1 causing rock bursts is transformed into a roof that is relatively broken and contains a large number of cavities. The transformed main controlling rock stratum 1 causing rock bursts is not prone to large-energy fracture events, reduces strong dynamic load disturbances, and can absorb the impact energy generated by other rock strata as a buffer cushion layer. The combined operation of hydraulic fracturing and hydraulic jet cavitation forms a complex hydraulic fracture network and a large area of cavities in the main controlling rock stratum 1 causing rock bursts. It improves the weakening degree of the hard main controlling rock stratum 1 causing rock bursts, expands the pressure relief range, is more likely to promote high-stress transfer and energy release, avoids the adverse impact of local pressure relief measures on the stability of roadway surrounding rock, effectively reduces the risk of rock bursts occurring in the working face, improves the construction efficiency of rock burst prevention in the main controlling rock stratum area, and reduces the construction cost of rock burst prevention.

[0049] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0050] In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0051] In the present invention, unless otherwise clearly specified and limited, the terms such as "installation", "connection", "connection", "fixation", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection, an electrical connection, or communicable with each other; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0052] In the present invention, unless otherwise clearly defined or limited, the first feature being "on" or "under" the second feature may mean that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Further, the first feature being "above", "over" and "on top of" the second feature may mean that the first feature is directly above or obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "below" and "beneath" the second feature may mean that the first feature is directly below or obliquely below the second feature, or merely indicates that the horizontal height of the first feature is less than that of the second feature.

[0053] In the present invention, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, without conflict, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0054] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for preventing and controlling rock burst, characterized in that: The following steps are involved: Step S1, classifying the roof rock layer above at least one of the tunnel to be treated and the working face to be mined, which has a thickness greater than or equal to a first preset value and a compressive strength greater than or equal to a second preset value, as the main rock layer causing rock burst disaster; Step S2, drilling a hole in the rock formation that controls the rock burst disaster; Step S3, hydraulically fracturing the main rock formation causing rock burst disaster by using the drill hole, so as to form a hydraulic fracture zone having hydraulic fractures in the main rock formation causing rock burst disaster; Step S4, opening a plurality of prevention and control caves connected to the hydraulic fracturing cracks in the hydraulic fracture area of ​​the main rock formation causing rock burst disaster; In the step S4, rock is cut outward from the borehole located in the hydraulic fracture zone to open a plurality of control caves; The borehole is divided into a plurality of sub-boreholes along the extension direction of the borehole, and the plurality of sub-boreholes are hydraulically fractured in sequence along the direction away from the bottom of the borehole, wherein after hydraulic fracturing is completed on one of the two adjacent sub-boreholes adjacent to the bottom of the borehole, rock is cut outward from the inside of one of the two adjacent sub-boreholes adjacent to the bottom of the borehole to open the control cave, and then hydraulic fracturing is performed on one of the two adjacent sub-boreholes away from the bottom of the borehole.

2. The method for preventing and controlling rock burst according to claim 1, characterized in that: The control caves include a first control cave; In the step S4, a position in the borehole located in the hydraulic fracture zone is taken as the center position of the first control cave, and then the rock is cut outward to form the first control cave.

3. The method for preventing and controlling rock burst according to claim 2, characterized in that: In the step S4, a plurality of the first prevention and control caves are provided in the hydraulic fracture area and distributed along the extension direction of the borehole.

4. The method for preventing and controlling rock burst according to claim 3, characterized in that: In step S4, the distance between two adjacent first prevention and control caves in the extension direction of the same borehole is greater than or equal to 10 meters.

5. The method for preventing and controlling rock burst according to claim 1, characterized in that: After the hydraulic fracturing of the borehole is completed, the rock is cut outward from multiple positions in the borehole in sequence in a direction away from the bottom of the borehole so as to open a plurality of control caves.

6. The method for preventing and controlling rock burst according to any one of claims 2 to 5, characterized in that: The diameter of the prevention and control cave is greater than or equal to 1 meter; In the step S2, there are multiple drill holes, and the multiple drill holes are arranged at intervals; In step S4, a hydraulic ejector is delivered to the borehole in the hydraulic fracture zone by a drilling rig, and the hydraulic ejector ejects jet water having a pressure greater than or equal to a third preset value to the rock in the hydraulic fracture zone so as to cut the rock.

7. The method for preventing and controlling rock burst according to claim 6, characterized in that: In the step S1, the top rock layer above at least one of the tunnel to be treated and the working face to be mined, whose thickness is greater than or equal to a first preset value and whose compressive strength is greater than or equal to a second preset value, is divided into multiple layers of the main rock layer causing rock burst disaster; In the step S2, the drill hole is opened upward from the formed tunnel, the horizontal extension direction of the drill hole and the extension direction of the tunnel to be treated are both in the first direction, a plurality of the drill holes are arranged at intervals in the second direction, and any two of the first direction, the second direction and the up-down direction are perpendicular to each other; In step S4, the top of the prevention and control cave is located at the top of the rock formation that controls rock burst disasters, and the bottom of the prevention and control cave is located at the bottom of the rock formation that controls rock burst disasters; In step S4, the pressure of the jet water is greater than or equal to 50 MPa.

8. The method for preventing and controlling rock burst according to claim 1, characterized in that: It also includes step S5. In step S5, after opening a plurality of the prevention and control caves, the working face to be mined is mined, and the rock burst prevention and control effect is evaluated based on microseismic monitoring during the mining process. The rock burst prevention and control effect can be improved by at least one of increasing the number of drill holes, increasing the number of the prevention and control caves, shortening the distance between two adjacent prevention and control caves, and increasing the hydraulic fracturing displacement.

Images