Coal mine roof deep hole hydraulic fracturing pressure relief energy storage anti-scouring method

Abstract

The present application relates to the technical field of coal mine, and particularly relates to a coal mine roof deep hole hydraulic fracturing pressure relief energy storage anti-scouring method, which comprises the following steps: determining a target horizon of a fracturing hole according to the characteristics of overburden strata of a working face, wherein the working face is formed between two crossheading, drilling is performed in at least one of the two crossheading to form the fracturing hole, at least part of the fracturing hole is located in the target horizon and extends along the extension direction of the crossheading, hydraulic fracturing is performed in the fracturing hole to cause the target horizon to crack, a piezoelectric element is installed in the fracturing hole by using a drilling machine, the piezoelectric element is used to deform to generate electric energy under the extrusion of the overburden strata, and the electric energy generated by the piezoelectric element is reused. The coal mine roof deep hole hydraulic fracturing pressure relief energy storage anti-scouring method of the present application can improve the mining safety while reducing the pressure relief cost.

Description

Technical Field

[0001] This invention relates to the field of coal mining technology, specifically to a method for deep-hole hydraulic fracturing, pressure relief, energy storage, and anti-scour of the roof of a coal mine. Background Technology

[0002] Rockburst is a phenomenon in which the elastic strain energy stored in deep rock masses is released instantaneously due to stress imbalance caused by excavation or geological activity under high stress conditions. When rockburst occurs, coal and rock are ejected, generating strong shock waves that affect the safety of coal seam mining, necessitating roof decompression.

[0003] However, the depressurization cost is relatively high when depressurizing the top plate in related technologies. Summary of the Invention

[0004] This invention is based on the inventor's discoveries and understanding of the following facts and problems:

[0005] The inventors recognized that during the mining process after hydraulic fracturing, the coal and rock above the working face would be continuously disturbed by dynamic loads. The relevant technologies did not recover the disturbance energy generated during the mining process, resulting in energy waste.

[0006] The present invention aims to at least partially solve one of the technical problems in the related art.

[0007] Therefore, embodiments of the present invention propose a method for deep-hole hydraulic fracturing and pressure relief energy storage to prevent erosion in coal mine roofs, which can improve mining safety while reducing pressure relief costs.

[0008] The coal mine roof deep-hole hydraulic fracturing pressure relief and energy storage anti-scour method according to an embodiment of the present invention includes: determining the target stratum of the fracturing hole based on the characteristics of the overlying strata on the working face, wherein the working face is formed between two roadways; drilling a hole in at least one of the two roadways to form a fracturing hole, at least a portion of the fracturing hole being located at the target stratum and extending along the extension direction of the roadway; performing hydraulic fracturing in the fracturing hole to fracture the target stratum; installing a piezoelectric element in the fracturing hole using a drilling rig, the piezoelectric element being used to deform under the compression of the overlying strata to generate electrical energy; and reusing the electrical energy generated by the piezoelectric element.

[0009] The deep-hole hydraulic fracturing and pressure relief energy storage method for coal mine roof protection in this embodiment of the invention can improve mining safety while reducing pressure relief costs.

[0010] In some embodiments, drilling to form a fracturing hole in at least one of the two roadways includes: drilling an inclined section of the fracturing hole in the at least one roadway at an angle upward along the extension direction of the roadway using a drilling rig, wherein the endpoint of the inclined section is located at the target layer; and drilling a fracturing section of the fracturing hole at the endpoint of the inclined section along the extension direction of the roadway using a drilling rig, wherein the fracturing section and the inclined section are arranged sequentially in the extension direction of the fracturing hole, and the fracturing section is located at the target layer.

[0011] In some embodiments, installing piezoelectric elements within the fracturing borehole using a drilling rig includes: sequentially installing a plurality of first piezoelectric elements within a fracturing section of the fracturing borehole using a drilling rig, wherein the piezoelectric element includes a first piezoelectric element and a second piezoelectric element, the plurality of first piezoelectric elements are spaced apart in the extension direction of the fracturing section, and the first piezoelectric elements abut against the inner wall surface of the fracturing section; and sequentially installing a plurality of second piezoelectric elements within a directional drilling section of the fracturing borehole using a drilling rig, the plurality of second piezoelectric elements being spaced apart in the extension direction of the directional drilling section and electrically connected to the first piezoelectric elements, the second piezoelectric elements abutting against the inner wall surface of the directional drilling section.

[0012] In some embodiments, both the first piezoelectric element and the second piezoelectric element include a piezoelectric body and a connecting portion, wherein the piezoelectric body is connected to the connecting portion, and the connecting portion of one of the two adjacent piezoelectric elements is used to electrically connect with the piezoelectric body of the other piezoelectric element.

[0013] In some embodiments, on a projection plane orthogonal to the thickness direction of the piezoelectric body, the projection of the piezoelectric body is an annular or fan-shaped annular shape, and the outer peripheral surface of the annular or fan-shaped annular shape abuts against the inner wall surface of the fracturing hole.

[0014] In some embodiments, the spacing between two adjacent piezoelectric elements in the first and second piezoelectric elements is 0.5m-1m.

[0015] In some embodiments, the spacing between the plurality of first piezoelectric elements in the fracturing section is smaller than the spacing between the plurality of second piezoelectric elements in the directional drilling section.

[0016] In some embodiments, the deep-hole hydraulic fracturing and pressure relief energy storage method for preventing erosion of the coal mine roof further includes: using a wire to electrically connect to the second piezoelectric element to discharge the electrical energy on the piezoelectric element.

[0017] In some embodiments, the fracturing hole includes a first hole and a second hole, the first hole and the second hole being arranged at intervals in the width direction of the groove.

[0018] In some embodiments, the fracturing section of the first hole and the fracturing section of the second hole are spaced 50m-70m apart in the width direction of the groove. Attached Figure Description

[0019] Figure 1 This is a flowchart of a method for deep-hole hydraulic fracturing, pressure relief, energy storage, and anti-scour of coal mine roof according to an embodiment of the present invention.

[0020] Figure 2 This is a schematic diagram of a piezoelectric element installed in a fracturing hole according to an embodiment of the present invention.

[0021] Figure 3 This is a schematic diagram of the first hole and the second hole in an embodiment of the present invention.

[0022] Figure 4 This is a schematic diagram of a piezoelectric element according to an embodiment of the present invention.

[0023] Figure label:

[0024] Coal seam 100,

[0025] Overlying strata 1, target stratum 11, mudstone 12, coarse-grained sandstone 13, fine-grained sandstone 14, sandy mudstone 15, siltstone 16.

[0026] 2nd haulage roadway

[0027] Fracturing hole 3, directional fracturing section 31, fracturing section 32, first hole 33, second hole 34.

[0028] Piezoelectric element 4, first piezoelectric element 41, second piezoelectric element 42, piezoelectric body 43, connecting part 44. Detailed Implementation

[0029] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0030] The following is in conjunction with the appendix Figures 1 to 4 The method for deep-hole hydraulic fracturing, pressure relief, energy storage, and anti-scour of coal mine roof in this embodiment is described in detail.

[0031] like Figure 1As shown, the coal mine roof deep-hole hydraulic fracturing pressure relief and energy storage anti-scour method of this embodiment includes: determining the target layer 11 of the fracturing hole 3 according to the characteristics of the overlying stratum 1 on the working face, wherein the working face is formed between two roadways 2; drilling a hole in at least one of the two roadways 2 to form a fracturing hole 3, at least a portion of the fracturing hole 3 being located at the target layer 11 and extending along the extension direction of the roadway 2; performing hydraulic fracturing in the fracturing hole 3 to fracture the target layer 11; installing a piezoelectric element 4 in the fracturing hole 3 using a drilling rig, the piezoelectric element 4 being used to deform under the squeezing action of the overlying stratum 1 to generate electrical energy; and reusing the electrical energy generated by the piezoelectric element 4.

[0032] The coal mine roof deep-hole hydraulic fracturing pressure relief and energy storage anti-scour method of this invention involves drilling a fracturing hole 3 in the overlying strata 1 in the roadway 2 to perform hydraulic fracturing, ensuring the hydraulic fracturing effect. After hydraulic fracturing, a piezoelectric element 4 is installed in the fracturing hole 3. The piezoelectric element 4 absorbs the dynamic disturbance energy of the overlying strata 1 during the mining of the coal seam 100, realizing safe mining while converting the mechanical energy generated by the overlying strata 1 into electrical energy for storage and utilization, improving energy utilization efficiency, and thus reducing pressure relief costs.

[0033] Furthermore, in this embodiment, the piezoelectric element 4 is installed in the fracturing hole 3 after hydraulic fracturing is performed in the fracturing hole 3, so that the hydraulic fracturing and the absorption of dynamic disturbance energy of the overlying rock layer 1 by the piezoelectric element 4 do not interfere with each other, thus avoiding the installation of the piezoelectric element 4 from affecting the flow of fracturing fluid and ensuring the hydraulic fracturing effect.

[0034] Specifically, such as Figures 1-3 As shown, the characteristics of the overburden stratum 1 on the working surface can be obtained through borehole columnar sections. These sections clearly display information such as lithology and thickness, facilitating the determination of the characteristics of the overburden stratum 1 on the working surface, and thus identifying the target stratum 11. It can be understood that the target stratum 11 is the thick, hard rock layer within the overburden stratum 1 on the working surface.

[0035] Drilling a fracturing hole 3 in at least one of the two roadways 2 includes: drilling a fracturing hole 3 in one of the two roadways 2; or drilling a fracturing hole 3 in the other of the two roadways 2; or drilling a fracturing hole 3 in each of the two roadways 2. In this embodiment, drilling a fracturing hole 3 in each of the two roadways 2 is performed, and the fracturing range of the fracturing hole 3 formed by drilling in one of the two roadways 2 and the fracturing range of the fracturing hole 3 formed by drilling in the other of the two roadways 2 cover the area above the working face.

[0036] Optionally, one of the two roadways 2 is a transport roadway 2, and the other is a return air roadway 2. One side of the roadway 2 in its width direction is the working face side, and the other side is the coal pillar side.

[0037] Optionally, when the coal seam 100 is thick (for example, when the coal seam 100 is thicker than 8m), a layered mining method can be adopted, that is, the roadway 2 is located in the middle of the coal seam 100.

[0038] After hydraulic fracturing in the fracturing hole 3, the fracturing fluid supply is stopped, and the piezoelectric element 4 is installed in the fracturing hole 3. Since the piezoelectric element 4 can deform and generate electrical energy under the squeezing action of the overlying rock stratum 1, the piezoelectric element 4 can absorb the dynamic disturbance energy of the overlying rock stratum 1 during the working face mining process, converting the mechanical energy of the overlying rock stratum 1 into electrical energy, realizing energy recovery and utilization, and improving energy utilization efficiency.

[0039] Optionally, the piezoelectric element 4 can be connected to electrical equipment (such as energy storage devices or power supply devices) in the channel 2 via wires to transmit the generated electrical energy to the electrical equipment, powering lighting, monitoring equipment or other electrical equipment in the channel 2, thereby realizing energy recovery and utilization.

[0040] For example, piezoelectric component 4 is a piezoelectric ceramic, a mass block-spring-generator system, a shape memory alloy, and heat recovery.

[0041] In some embodiments, drilling to form a fracturing hole 3 in at least one of two roadways 2 includes: drilling an inclined section 31 in at least one roadway 2 along the extension direction of the roadway 2 using a drilling rig to form a fracturing hole 3, wherein the endpoint of the inclined section 31 is located at the target layer 11; and drilling a fracturing section 32 at the endpoint of the inclined section 31 along the extension direction of the roadway 2 using a drilling rig to form a fracturing hole 3, wherein the fracturing section 32 and the inclined section 31 are arranged sequentially in the extension direction of the fracturing hole 3, and the fracturing section 32 is located at the target layer 11.

[0042] Specifically, such as Figure 2 and Figure 3 As shown, the fracturing hole 3 includes a directional drilling section 31 and a fracturing section 32 arranged sequentially along the extension direction of the fracturing hole 3. The directional drilling section 31 extends along the extension direction of the trench 2 and is arranged obliquely upwards. The endpoint of the directional drilling section 31 is located at the middle position of the target layer 11 in the vertical direction. The fracturing section 32 is located in the target layer 11 and extends along the extension direction of the trench 2. Since the fracturing section 32 and the trench 2 are arranged at intervals in the vertical direction and extend along the extension direction of the trench 2, the directional drilling section 31 can guide the drill bit to the target layer 11, reducing the construction difficulty of the fracturing section 32 and improving drilling efficiency.

[0043] In some embodiments, installing piezoelectric elements 4 within a fracturing borehole 3 using a drilling rig includes: sequentially installing a plurality of first piezoelectric elements 41 within a fracturing section 32 of the fracturing borehole 3 using a drilling rig, wherein the piezoelectric element 4 includes first piezoelectric elements 41 and second piezoelectric elements 42, the plurality of first piezoelectric elements 41 being spaced apart in the extending direction of the fracturing section 32, and the first piezoelectric elements 41 abutting against the inner wall surface of the fracturing section 32; and sequentially installing a plurality of second piezoelectric elements 42 within a directional fracturing section 31 of the fracturing borehole 3 using a drilling rig, the plurality of second piezoelectric elements 42 being spaced apart in the extending direction of the directional fracturing section 31 and electrically connected to the first piezoelectric elements 41, and the second piezoelectric elements 42 abutting against the inner wall surface of the directional fracturing section 31.

[0044] Specifically, such as Figure 2 and Figure 3 As shown, the first piezoelectric element 41 is installed in the fracturing hole 3 by the drilling machine and abuts against the inner wall of the fracturing section 32 so that the first piezoelectric element 41 can better receive the extrusion from the overlying rock layer 1 of the fracturing section 32. By converting the mechanical energy of the overlying rock layer 1 at the fracturing section 32 into electrical energy, the energy can be recovered and utilized.

[0045] The second piezoelectric element 42 is installed in the fracturing hole 3 by the drilling rig and abuts against the inner wall of the inclined section 31. On the one hand, it facilitates the discharge of the electrical energy converted by the first piezoelectric element 41 in the fracturing section 32. On the other hand, it facilitates the second piezoelectric element 42 to better receive the compression from the overlying rock layer 1 of the inclined section 31, so as to convert the mechanical energy of the overlying rock layer 1 at the inclined section 31 into electrical energy, and further improve the energy recovery and utilization rate.

[0046] Optionally, the spaced arrangement of multiple first piezoelectric elements 41 makes it easier for the first piezoelectric elements 41 to deform under the pressure of the overlying rock layer 1, thereby improving the conversion efficiency of the first piezoelectric elements 41. The spaced arrangement of multiple second piezoelectric elements 42 makes it easier for the second piezoelectric elements 42 to deform under the pressure of the overlying rock layer 1, thereby improving the conversion efficiency of the second piezoelectric elements 42.

[0047] Optionally, the plurality of first piezoelectric elements 41 are electrically connected to each other, and the plurality of second piezoelectric elements 42 are electrically connected to each other and to the first piezoelectric elements 41, so as to facilitate the export of electrical energy converted by the first piezoelectric elements 41 through the second piezoelectric elements 42.

[0048] In this embodiment, the first piezoelectric element 41 and the second piezoelectric element 42 deform under the compression of the overlying rock layer 1 to convert mechanical energy into electrical energy, thereby realizing energy recovery. The second piezoelectric element 42 installed in the inclined section 31 is electrically connected to the first piezoelectric element 41 installed in the fracturing section 32 to transmit the electrical energy converted by the first piezoelectric element 41 to the second piezoelectric element 42. The second piezoelectric element 42 is connected to external electrical equipment or energy storage equipment to realize energy storage and utilization.

[0049] Optionally, the second piezoelectric element 42 can be connected to an external electrical device or energy storage device via a wire.

[0050] In some embodiments, the first piezoelectric element 41 and the second piezoelectric element 42 each include a piezoelectric body 43 and a connecting portion 44. The piezoelectric body 43 is connected to the connecting portion 44. The connecting portion 44 of one of the two adjacent piezoelectric elements 4 is used to electrically connect with the piezoelectric body 43 of the other piezoelectric element 4.

[0051] Specifically, such as Figure 4 As shown, the piezoelectric body 43 is electrically connected to the connecting part 44. For ease of description, three piezoelectric elements 4 are used as an example. The first piezoelectric element 4, the second piezoelectric element 4, and the third piezoelectric element 4 are arranged sequentially at intervals in the extension direction of the fracturing hole 3. The second piezoelectric element 4 is located between the first piezoelectric element 4 and the third piezoelectric element 4, and the first piezoelectric element 4 is closer to the end position of the fracturing hole 3 than the third piezoelectric element 4. The connecting part 44 of the first piezoelectric element 4 is connected to the piezoelectric body 43 of the second piezoelectric element 4, and the connecting part 44 of the second piezoelectric element 4 is connected to the piezoelectric body 43 of the third piezoelectric element 4, and so on. This allows the electrical energy converted by the first piezoelectric element 4 to be sequentially discharged to the outside of the fracturing hole 3 through multiple first piezoelectric elements 41 and multiple second piezoelectric elements 42.

[0052] In some embodiments, such as Figure 4 As shown, on a projection plane orthogonal to the thickness direction of the piezoelectric body 43, the projection of the piezoelectric body 43 is an annular or fan-shaped ring, and the outer peripheral surface of the annular or fan-shaped ring abuts against the inner wall surface of the fracturing hole 3. By setting the piezoelectric body 43 as an annular or fan-shaped ring, it is easier for the outer peripheral surface of the piezoelectric body 43 to abut against the inner wall surface of the fracturing hole 3, thereby facilitating the deformation of the piezoelectric body 43 under the pressure of the overlying rock layer 1 and improving the conversion efficiency of the piezoelectric element 4.

[0053] Optionally, the piezoelectric body 43 in this embodiment is annular. The annular piezoelectric body 43 can increase the contact area between the piezoelectric element 4 and the inner wall of the fracture hole 3, thereby improving the conversion efficiency of the piezoelectric element 4.

[0054] In some embodiments, the spacing between two adjacent piezoelectric elements 4 in the first piezoelectric element 41 and the second piezoelectric element 42 is 0.5m-1m.

[0055] Specifically, such as Figure 2 and Figure 3As shown, the spacing between two adjacent piezoelectric elements 4 in the first piezoelectric element 41 and the second piezoelectric element 42 can be understood as the spacing between two adjacent first piezoelectric elements 41, or the spacing between two adjacent second piezoelectric elements 42, or the distance between two adjacent first piezoelectric elements 41 and second piezoelectric elements 42. By limiting the distance between two adjacent piezoelectric elements 4, on the one hand, it avoids the spacing between two adjacent piezoelectric elements 4 being too large, resulting in some energy not being absorbed and being wasted; on the other hand, it avoids the spacing between two adjacent piezoelectric elements 4 being too small, resulting in the absorption range of adjacent piezoelectric elements 4 overlapping and reducing the energy absorption rate, thus ensuring the absorption range and conversion efficiency of the piezoelectric elements 4.

[0056] For example, the spacing between two adjacent piezoelectric elements 4 is 0.5m, 0.7m, 0.9m, and 1m.

[0057] In some embodiments, the spacing between the plurality of first piezoelectric elements 41 in the fracturing section 32 is smaller than the spacing between the plurality of second piezoelectric elements 42 in the inclined section 31.

[0058] Specifically, such as Figure 2 As shown, above coal seam 100 are, in sequence, mudstone 12, coarse-grained sandstone 13, mudstone 12, fine-grained sandstone 14, sandy mudstone 15, siltstone 16, sandy mudstone 15, and coarse-grained sandstone 13. Among them, mudstone 12 is 3.4m, coarse-grained sandstone 13 is 5.7m, mudstone 12 is 4m, fine-grained sandstone 14 is 10.2m, sandy mudstone 15 is 5.75m, siltstone 16 is 5.4m, sandy mudstone 15 is 6.6m, and coarse-grained sandstone 13 is 5.5m.

[0059] Since the target stratum 11 is a sandstone layer with a thickness greater than 8m within 30m above the coal seam 100, and the fine-grained sandstone 14 has a thickness of 10.2m, the fine-grained sandstone 14 is the target rock layer. The directional section 31 of the fracturing hole 3 needs to pass through mudstone 12, coarse-grained sandstone 13 and mudstone 12 in sequence to reach the fine-grained sandstone 14 of the target stratum 11. The fracturing section 32 extends along the extension direction of the roadway 2 in the target stratum 11. Since the target stratum 11 is subjected to the most significant impact, by arranging the first piezoelectric element 41 more densely in the target stratum 11, it is beneficial for the first piezoelectric element 41 to absorb the energy of the overlying rock layer 1 of the target stratum 11, thereby improving the conversion efficiency of the first piezoelectric element 41 and thus improving the energy recovery efficiency.

[0060] In some embodiments, the deep-hole hydraulic fracturing pressure relief and energy storage method for preventing erosion in coal mine roofs further includes: using a wire to electrically connect to a second piezoelectric element 42 to discharge electrical energy from the piezoelectric element 4. The wire is connected to the outermost second piezoelectric element 42 among a plurality of second piezoelectric elements 42. The arrangement of the wire facilitates the discharge of electrical energy converted by the first piezoelectric element 41 and the second piezoelectric element 42 to the fracturing hole 3 for use.

[0061] Optionally, the piezoelectric body 43 of the innermost second piezoelectric element 42 is electrically connected to the connecting portion 44 of the outermost first piezoelectric element 41 among the plurality of first piezoelectric elements 41.

[0062] In some embodiments, the fracturing hole 3 includes a first hole 33 and a second hole 34, which are arranged at intervals in the width direction of the groove 2.

[0063] Specifically, such as Figure 3 As shown, the first hole 33 extends towards the working face side, and the second hole 34 extends towards the coal pillar side. The first hole 33 and the second hole 34 are arranged approximately symmetrically, which facilitates simultaneous hydraulic fracturing of both sides of the roadway 2 in its width direction, ensuring that the thick hard roof area of ​​the overlying rock strata 100 can be covered, and avoiding the occurrence of pre-fracturing blind zones.

[0064] It is understandable that the slant section 31 of the fracturing hole 3 extends away from the roadway 2 in the width direction of the roadway 2, so that the fracturing section 32 and the roadway 2 are arranged at intervals in the width direction of the roadway 2, so as to avoid the fracturing range of the first hole 33 and the fracturing range of the second hole 34 from overlapping, and to avoid the appearance of a blank zone between the first hole 33 and the second hole 34, thus ensuring the depressurization effect of the top plate.

[0065] In some embodiments, such as Figure 3 As shown, the fracturing sections 32 of the first hole 33 and the second hole 34 are spaced 50m-70m apart in the width direction of the roadway 2. By limiting the distance between the fracturing sections 32 of the first hole 33 and the second hole 34 in the width direction of the roadway 2, gaps between the first hole 33 and the second hole 34 are avoided, ensuring the depressurization effect of the roof.

[0066] Since the fracture extension range of hydraulic fracturing section 32 is 20-40m, in this embodiment, the fracturing section 32 of the first hole 33 and the fracturing section 32 of the second hole 34 are spaced 60m apart in the width direction of the channel 2 to avoid blank zones and improve the pressure relief effect.

[0067] For example, the length of the opening and closing positions of fracturing hole 3 is 600m.

[0068] This invention employs deep-hole hydraulic fracturing of the roof to perform high-energy hydraulic fracturing on the thick, hard roof of the working face to be mined. This reduces the original rock stress and tectonic stress levels in the working face to be mined in the roadway 2 from the perspective of the power source structure, thereby achieving safe mining of the working face in a low-stress area and preventing rockburst at the source. After hydraulic fracturing, multiple piezoelectric elements 4 are continuously arranged in the fracturing hole 3 to convert the energy released by the controllable coal blasts in the coal and rock mass affected by mining into electrical energy, which can then be stored and utilized.

[0069] In this embodiment, deep-hole hydraulic fracturing of the roof of the working face is used to place the roadway 2 in a low-stress zone, enabling safe mining. Moreover, during the mining of the working face, the piezoelectric element 4 converts the disturbance energy of the overlying rock stratum 1 into electrical energy, thereby converting the mechanical energy of the overlying rock stratum 1 into electrical energy, effectively reducing the stress concentration and achieving pressure relief and energy storage synergy.

[0070] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0071] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0072] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0073] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0074] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0075] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled 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 deep-hole hydraulic fracturing, pressure relief, energy storage, and scour prevention of coal mine roof, characterized in that, include: The target stratum of the fracturing hole is determined based on the characteristics of the overburden strata on the working face, wherein the working face is formed between two roadways; A fracturing hole is formed by drilling in at least one of the two roadways, at least a portion of the fracturing hole being located in the target layer and extending along the extension direction of the roadway; Hydraulic fracturing is performed within the fracturing borehole to fracture the target layer; A piezoelectric element is installed in the fracturing hole using a drilling rig. The piezoelectric element is used to generate electrical energy by deforming under the compression of the overlying rock strata. The electrical energy generated by the piezoelectric element can be reused; Drilling a fracturing hole in at least one of the two roadways includes: A drilling rig is used to drill an inclined section in the at least one roadway along the extension direction of the roadway to form a fracturing hole, wherein the end point of the inclined section is located at the target layer. A drilling rig is used to drill a hole along the extension direction of the roadway at the end of the directional drilling section to form a fracturing section of the fracturing hole, wherein the fracturing section and the directional drilling section are arranged sequentially in the extension direction of the fracturing hole, and the fracturing section is located at the target layer. Installing the piezoelectric element inside the fracturing borehole using a drilling rig includes: The piezoelectric element includes a first piezoelectric element and a second piezoelectric element; A plurality of first piezoelectric elements are sequentially installed in the fracturing section of the fracturing hole using a drilling rig. The plurality of first piezoelectric elements are arranged at intervals in the extension direction of the fracturing section, and the first piezoelectric elements abut against the inner wall surface of the fracturing section. Using a drilling rig, multiple second piezoelectric elements are sequentially installed in the directional drilling section of the fracturing hole. The multiple second piezoelectric elements are spaced apart in the extension direction of the directional drilling section and electrically connected to the first piezoelectric element. The second piezoelectric elements abut against the inner wall surface of the directional drilling section. Both the first piezoelectric element and the second piezoelectric element include a piezoelectric body and a connecting portion. The piezoelectric body is connected to the connecting portion. The connecting portion of one of the two adjacent piezoelectric elements is used to electrically connect with the piezoelectric body of the other piezoelectric element. On a projection plane orthogonal to the thickness direction of the piezoelectric body, the projection of the piezoelectric body is an annular or fan-shaped annular shape, and the outer peripheral surface of the annular or fan-shaped annular shape abuts against the inner wall surface of the fracturing hole. The fracturing holes include a first hole and a second hole, which are arranged at intervals in the width direction of the groove; The fracturing sections of the first hole and the second hole are spaced 50m-70m apart in the width direction of the groove.

2. The method for deep-hole hydraulic fracturing, pressure relief, energy storage, and scour prevention of coal mine roof as described in claim 1, characterized in that, The spacing between two adjacent piezoelectric elements in the first and second piezoelectric elements is 0.5m-1m.

3. The method for deep-hole hydraulic fracturing, pressure relief, energy storage, and scour prevention of coal mine roof as described in claim 1, characterized in that, The spacing between the plurality of first piezoelectric elements in the fracturing section is less than the spacing between the plurality of second piezoelectric elements in the directional drilling section.

4. The method for deep-hole hydraulic fracturing, pressure relief, energy storage, and scour prevention of coal mine roof as described in claim 1, characterized in that, Also includes: Electrical energy is extracted from the piezoelectric element by connecting it to the second piezoelectric element via a wire.

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