Coal mine roof deep hole hydraulic fracturing pressure relief energy storage scour prevention method

Abstract

The invention relates to the technical field of coal mines, in particular to a coal mine roof deep hole hydraulic fracturing pressure relief energy storage anti-scour method which comprises the steps that the target layer position of a fracturing hole is determined according to the characteristics of an overlying rock layer on a working face, the working face is formed between two crossheading, and the target layer position of the fracturing hole is determined according to the characteristics of the overlying rock layer on the working face; drilling is conducted in at least one of the two crossheads to form a fracturing hole, at least part of the fracturing hole is located in the target layer and extends in the extending direction of the crossheads, hydraulic fracturing is conducted in the fracturing hole to crack the target layer, a piezoelectric piece is installed in the fracturing hole through a drilling machine, and the piezoelectric piece is installed in the fracturing hole; the piezoelectric piece is used for deforming under the extrusion effect of the overlying rock stratum so as to generate electric energy, and the electric energy generated by the piezoelectric piece is reused. According to the coal mine roof deep hole hydraulic fracturing pressure relief energy storage scour prevention method, the mining safety can be improved, and meanwhile the pressure relief cost can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of coal mines, and in particular to a method for preventing impact by hydraulic fracturing and pressure relief and energy storage in deep holes of a coal mine roof. Background Art

[0002] Rock burst occurs when deep rock masses experience high stresses, leading to stress imbalances caused by excavation or geological activity, and the instantaneous release of stored elastic strain energy. Rock burst can cause coal and rock to be ejected, generating a strong shock wave that compromises coal mining safety and necessitates roof decompression.

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

[0004] The present invention is based on the inventor's discovery and understanding of the following facts and problems:

[0005] The inventors realized that when the working face is mined after hydraulic fracturing, the mining process will generate continuous dynamic load disturbances on the coal rock above the working face roof. The related art does not recover the disturbance energy generated during the mining process, resulting in energy waste.

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

[0007] To this end, an embodiment of the present invention proposes a coal mine roof deep hole hydraulic fracturing pressure relief energy storage and anti-blowout method, which can improve mining safety while reducing pressure relief costs.

[0008] The coal mine roof deep hole hydraulic fracturing pressure relief energy storage and anti-bumping method according to an embodiment of the present invention includes: determining the target layer of the fracturing hole according to the characteristics of the overlying rock formation on the working face, wherein the working face is formed between two inclined grooves; drilling a fracturing hole in at least one of the two inclined grooves, wherein at least a portion of the fracturing hole is located in the target layer and extends along the extension direction of the inclined groove; hydraulic fracturing is performed in the fracturing hole to fracture the target layer; a piezoelectric element is installed in the fracturing hole by using a drilling rig, wherein the piezoelectric element is used to deform under the squeezing action of the overlying rock formation to generate electrical energy; and the electrical energy generated by the piezoelectric element is reused.

[0009] The coal mine roof deep hole hydraulic fracturing pressure relief energy storage and anti-blowout method according to the embodiment of the present invention can improve mining safety while reducing pressure relief costs.

[0010] In some embodiments, drilling is performed in at least one of the two longitudinal slots to form a fracturing hole, comprising: using a drilling rig to drill a hole obliquely upward in the at least one longitudinal slot along the extension direction of the longitudinal slot to form a deflection section of the fracturing hole, wherein the end point of the deflection section is located at the target layer; using a drilling rig to drill a hole along the extension direction of the longitudinal slot at the end point of the deflection section to form a fracturing section of the fracturing hole, wherein the fracturing section and the deflection section are arranged in sequence in the extension direction of the fracturing hole, and the fracturing section is located at the target layer.

[0011] In some embodiments, a piezoelectric component is installed in the fracturing hole using a drilling rig, comprising: using a drilling rig to sequentially install a plurality of first piezoelectric components in the fracturing section of the fracturing hole, wherein the piezoelectric component includes a first piezoelectric component and a second piezoelectric component, and the plurality of first piezoelectric components are arranged at intervals in the extension direction of the fracturing section, and the first piezoelectric component abuts against the inner wall surface of the fracturing section; using a drilling rig to sequentially install a plurality of second piezoelectric components in the inclination section of the fracturing hole, and the plurality of second piezoelectric components are arranged at intervals in the extension direction of the inclination section and are electrically connected to the first piezoelectric component, and the second piezoelectric component abuts against the inner wall surface of the inclination section.

[0012] In some embodiments, the first piezoelectric element and the second piezoelectric element each include a piezoelectric body and a connecting portion, 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 to the piezoelectric body of the other of the two adjacent piezoelectric elements.

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

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

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

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

[0017] In some embodiments, the fracturing holes include a first hole and a second hole, and the first hole and the second hole are spaced apart in a width direction of the trench.

[0018] In some embodiments, the fracturing section of the first hole and the fracturing section of the second hole are spaced apart by a distance of 50 m to 70 m in the width direction of the trench. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The present invention is a flowchart of a method for preventing erosion by hydraulic fracturing and storing pressure to release energy in deep holes of a coal mine roof.

[0020] Figure 2 Schematic diagram of a piezoelectric component installed in a fracturing hole according to an embodiment of the present invention.

[0021] Figure 3 Schematic diagram of the first hole and the second hole in an embodiment of the present invention.

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

[0023] Reference numerals:

[0024] Coal seam 100,

[0025] Overburden 1, target layer 11, mudstone 12, coarse-grained sandstone 13, fine-grained sandstone 14, sandy mudstone 15, siltstone 16,

[0026] Chute 2,

[0027] Fracturing hole 3, deflection 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 portion 44 . DETAILED DESCRIPTION

[0029] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

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

[0031] like Figure 1As shown, the coal mine roof deep hole hydraulic fracturing pressure relief energy storage and anti-bumping method of an embodiment of the present invention includes: determining the target layer 11 of the fracturing hole 3 according to the characteristics of the overlying rock 1 on the working face, wherein the working face is formed between two inclined grooves 2; drilling in at least one of the two inclined grooves 2 to form a fracturing hole 3, at least part of the fracturing hole 3 is located in the target layer 11 and extends along the extension direction of the inclined groove 2; hydraulic fracturing is performed in the fracturing hole 3 to fracture the target layer 11; a piezoelectric element 4 is installed in the fracturing hole 3 by using a drilling rig, and the piezoelectric element 4 is used to deform under the squeezing action of the overlying rock 1 to generate electrical energy; and the electrical energy generated by the piezoelectric element 4 is reused.

[0032] The coal mine roof deep hole hydraulic fracturing pressure relief energy storage and anti-bumping method of the embodiment of the present invention is to perform hydraulic fracturing by drilling holes 3 in the overlying rock stratum 1 in the drift 2 to ensure the hydraulic fracturing effect, and install a piezoelectric element 4 in the fracturing hole 3 after hydraulic fracturing. The piezoelectric element 4 is used to absorb the dynamic disturbance energy of the overlying rock stratum 1 during the mining process of the coal seam 100, thereby achieving safe mining and converting the mechanical energy generated by the overlying rock stratum 1 into electrical energy for storage and utilization, thereby improving energy utilization and reducing the pressure relief cost.

[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 piezoelectric element 4 absorbing the dynamic disturbance energy of the overlying rock stratum 1 do not interfere with each other, avoiding the installation of the piezoelectric element 4 affecting the flow of the fracturing fluid, thereby ensuring the hydraulic fracturing effect.

[0034] Specifically, if Figure 1-Figure 3 As shown, the characteristics of the overburden stratum 1 on the working face can be obtained through the drill hole histogram, which can clearly display information such as the lithology and thickness of the rock formation, making it easier to determine the characteristics of the overburden stratum 1 on the working face and then determine the target horizon 11. It can be understood that the target horizon 11 is a thick and hard rock layer in the overburden stratum 1 on the working face.

[0035] Drilling is performed in at least one of the two chutes 2 to form a fracturing hole 3, including: drilling in one of the two chutes 2 to form a fracturing hole 3; or, drilling in the other of the two chutes 2 to form a fracturing hole 3; or, drilling is performed in both chutes 2 to form a fracturing hole 3. In this embodiment, drilling is performed in both chutes 2 to form a fracturing hole 3, and the fracturing range of the fracturing hole 3 drilled in one of the two chutes 2 and the fracturing range of the fracturing hole 3 drilled in the other of the two chutes 2 cover above the working face.

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

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

[0038] After hydraulic fracturing is performed in the fracturing hole 3, the delivery of the fracturing fluid is stopped and the piezoelectric element 4 is installed in the fracturing hole 3. Since the piezoelectric element 4 can be deformed 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 recovery process, and convert the mechanical energy of the overlying rock stratum 1 into electrical energy, thereby realizing energy recovery and improving energy utilization.

[0039] Optionally, the piezoelectric element 4 can be connected to electrical equipment (such as an energy storage device or a power supply device) in the chute 2 through a wire to transmit the generated electrical energy to the electrical equipment to power lighting, monitoring equipment or other electrical equipment in the chute 2, thereby realizing energy recovery and utilization.

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

[0041] In some embodiments, drilling is performed in at least one of the two longitudinal slots 2 to form a fracturing hole 3, including: using a drilling rig to drill obliquely upward in the extension direction of the longitudinal slot 2 in at least one longitudinal slot 2 to form a deflection section 31 of the fracturing hole 3, wherein the end point of the deflection section 31 is located at the target layer 11; using a drilling rig to drill at the end point of the deflection section 31 along the extension direction of the longitudinal slot 2 to form a fracturing section 32 of the fracturing hole 3, wherein the fracturing section 32 and the deflection section 31 are arranged in sequence in the extension direction of the fracturing hole 3, and the fracturing section 32 is located at the target layer 11.

[0042] Specifically, if Figure 2 and Figure 3 As shown, the fracturing hole 3 includes a deflection section 31 and a fracturing section 32, which are arranged in sequence along the extension direction of the fracturing hole 3. The deflection section 31 extends along the extension direction of the longitudinal channel 2 and is arranged obliquely upward. The end point of the deflection section 31 is located in 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 longitudinal channel 2. Because the fracturing section 32 is arranged vertically spaced from the longitudinal channel 2 and extends along the extension direction of the longitudinal channel 2, the provision of the deflection 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, a drilling rig is used to install the piezoelectric element 4 in the fracturing hole 3, including: using a drilling rig to sequentially install multiple first piezoelectric elements 41 in the fracturing section 32 of the fracturing hole 3, wherein the piezoelectric element 4 includes a first piezoelectric element 41 and a second piezoelectric element 42, and the multiple first piezoelectric elements 41 are arranged at intervals in the extension direction of the fracturing section 32, and the first piezoelectric elements 41 abut against the inner wall surface of the fracturing section 32; using a drilling rig to sequentially install multiple second piezoelectric elements 42 in the beveling section 31 of the fracturing hole 3, the multiple second piezoelectric elements 42 are arranged at intervals in the extension direction of the beveling section 31 and are electrically connected to the first piezoelectric elements 41, and the second piezoelectric elements 42 abut against the inner wall surface of the beveling section 31.

[0044] Specifically, if Figure 2 and Figure 3 As shown, the first piezoelectric element 41 is installed in the fracturing hole 3 through a drilling rig and abuts against the inner wall surface of the fracturing section 32, so that the first piezoelectric element 41 can better receive the extrusion of the overlying stratum 1 from the fracturing section 32, and realize energy recovery and utilization by converting the mechanical energy of the overlying stratum 1 at the fracturing section 32 into electrical energy.

[0045] The second piezoelectric element 42 is installed in the fracturing hole 3 through a drilling rig and abuts against the inner wall surface of the bend section 31. On the one hand, it is convenient for the electric energy converted by the first piezoelectric element 41 in the fracturing section 32 to be discharged. On the other hand, it is convenient for the second piezoelectric element 42 to better receive the extrusion of the overlying rock stratum 1 from the bend section 31, so as to convert the mechanical energy of the overlying rock stratum 1 at the bend section 31 into electric energy, thereby further improving the energy recovery rate.

[0046] Optionally, the multiple first piezoelectric elements 41 are arranged at intervals so that the first piezoelectric elements 41 are easily deformed under the compression of the overburden stratum 1, thereby improving the conversion efficiency of the first piezoelectric elements 41. The multiple second piezoelectric elements 42 are arranged at intervals so that the second piezoelectric elements 42 are easily deformed under the compression of the overburden stratum 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 extraction of the 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 are deformed under the compression of the overlying rock stratum 1 to convert mechanical energy into electrical energy, thereby realizing energy recovery. The second piezoelectric element 42 installed in the beveling 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 an external electrical device or energy storage device to realize energy storage and utilization.

[0049] Optionally, the second piezoelectric element 42 may 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 both include a piezoelectric body 43 and a connecting portion 44, the piezoelectric body 43 is connected to the connecting portion 44, and the connecting portion 44 of one piezoelectric element 4 among the two adjacent piezoelectric elements 4 is used to electrically connect to the piezoelectric body 43 of the other piezoelectric element 4 among the two adjacent piezoelectric elements 4.

[0051] Specifically, if Figure 4 As shown, the piezoelectric body 43 is electrically connected to the connecting portion 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 sequentially spaced apart in the extension direction of the fracturing hole 3. The second piezoelectric element 4 is located between the first and third piezoelectric elements 4, and the first piezoelectric element 4 is closer to the terminal position of the fracturing hole 3 than the third piezoelectric element 4. The connecting portion 44 of the first piezoelectric element 4 is connected to the piezoelectric body 43 of the second piezoelectric element 4, and the connecting portion 44 of the second piezoelectric element 4 is connected to the piezoelectric body 43 of the third piezoelectric element 4, and so on. This realizes that the electrical energy converted by the first piezoelectric element 4 is sequentially conducted out of the fracturing hole 3 through the multiple first piezoelectric elements 41 and the multiple second piezoelectric elements 42.

[0052] In some embodiments, as Figure 4 As shown, on a projection plane perpendicular to the thickness direction of the piezoelectric body 43, the projection of the piezoelectric body 43 is annular or sector-shaped, and the outer peripheral surface of the annular or sector-shaped piezoelectric body 43 abuts the inner wall surface of the fracturing hole 3. By configuring the piezoelectric body 43 in an annular or sector-shaped shape, the outer peripheral surface of the piezoelectric body 43 is facilitated to abut the inner wall surface of the fracturing hole 3, thereby facilitating the deformation of the piezoelectric body 43 under the compression of the overburden stratum 1, thereby improving the conversion efficiency of the piezoelectric element 4.

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

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

[0055] Specifically, if Figure 2 and Figure 3As shown, the spacing distance between two adjacent piezoelectric elements 4 in the first piezoelectric element 41 and the second piezoelectric element 42 can be understood as the spacing distance between two adjacent first piezoelectric elements 41, or the spacing distance 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 is prevented that the spacing between two adjacent piezoelectric elements 4 is too large, resulting in some energy not being absorbed and wasted, and on the other hand, it is prevented that the spacing between two adjacent piezoelectric elements 4 is too small, resulting in the overlapping absorption ranges of adjacent piezoelectric elements 4 and a reduced energy absorption rate, thereby ensuring the absorption range and conversion efficiency of the piezoelectric elements 4.

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

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

[0058] Specifically, if Figure 2 As shown, above the coal seam 100 are 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 which 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 layer 11 is a sandstone layer with a thickness greater than 8m within 30m above the coal seam 100, and the thickness of the fine-grained sandstone 14 is 10.2m, the fine-grained sandstone 14 is the target rock layer. The deflection section 31 of the fracturing hole 3 needs to pass through the mudstone 12, the coarse-grained sandstone 13 and the mudstone 12 in sequence to reach the fine-grained sandstone 14 of the target layer 11, and the fracturing section 32 extends in the target layer 11 along the extension direction of the trench 2. Since the target layer 11 is most significantly impacted, by arranging the first piezoelectric elements 41 more densely in the target layer 11, it is beneficial for the first piezoelectric elements 41 to absorb the energy of the overlying rock layer 1 of the target layer 11, thereby improving the conversion efficiency of the first piezoelectric elements 41 and thus improving the energy recovery efficiency.

[0060] In some embodiments, the coal mine roof deep hole hydraulic fracturing pressure relief energy storage and anti-bumping method further includes: electrically connecting the second piezoelectric element 42 with a wire to conduct the electrical energy from the piezoelectric element 4. The wire is connected to the outermost second piezoelectric element 42 of the plurality of second piezoelectric elements 42. The provision of the wire facilitates conducting the electrical energy converted by the first piezoelectric element 41 and the second piezoelectric element 42 out of the fracturing hole 3 for utilization.

[0061] Optionally, the piezoelectric body 43 of the innermost second piezoelectric element 42 among the plurality of second piezoelectric elements 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 holes 3 include a first hole 33 and a second hole 34 , and the first hole 33 and the second hole 34 are spaced apart in the width direction of the trench 2 .

[0063] Specifically, if Figure 3 As shown, the first hole 33 extends toward the working face side, and the second hole 34 extends toward the coal pillar side. The first hole 33 and the second hole 34 are roughly symmetrically arranged, so as to facilitate hydraulic fracturing of both sides of the drift 2 in its width direction at the same time, ensuring that the thick hard roof area of the overlying rock layer 1 of the coal seam 100 can be covered, thereby avoiding the occurrence of pre-cracking blind spots.

[0064] It can be understood that the inclined section 31 of the fracturing hole 3 extends in the width direction of the longitudinal channel 2 in the direction away from the longitudinal channel 2, so that the fracturing section 32 and the longitudinal channel 2 are arranged at intervals in the width direction of the longitudinal channel 2, avoiding the fracturing range of the first hole 33 and the fracturing range of the second hole 34 from overlapping, while avoiding the appearance of a blank zone between the first hole 33 and the second hole 34, thereby ensuring the pressure relief effect of the top plate.

[0065] In some embodiments, as Figure 3 As shown, the distance between the fracturing section 32 of the first hole 33 and the fracturing section 32 of the second hole 34 in the width direction of the longitudinal channel 2 is 50m-70m. By limiting the distance between the fracturing section 32 of the first hole 33 and the fracturing section 32 of the second hole 34 in the width direction of the longitudinal channel 2, a blank zone is avoided between the first hole 33 and the second hole 34, ensuring the pressure relief effect of the roof.

[0066] Since the crack expansion range of the hydraulic fracturing section 32 is 20-40m, in this embodiment, the distance between the fracturing section 32 of the first hole 33 and the fracturing section 32 of the second hole 34 in the width direction of the longitudinal groove 2 is set to 60m to avoid the occurrence of blank zones and improve the pressure relief effect.

[0067] For example, the length between the opening position and the end position of the fracturing hole 3 is 600 m.

[0068] The embodiment of the present invention adopts deep-hole hydraulic fracturing of the roof, and implements high-energy hydraulic fracturing on the thick and hard roof in the area to be mined of the working face, thereby regionally and proactively reducing the original rock stress and structural stress level of the area to be mined in the drift 2 from the perspective of the force source structure, thereby achieving safe mining of the working face in the low-stress area, and preventing and controlling rock burst 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 gun of the coal rock mass in the mining-affected area of the mining working face into electrical energy, which is then stored and utilized.

[0069] In this embodiment, deep holes in the roof of the working face are hydraulically fractured to place the drift 2 in a low stress zone, thereby achieving safe mining. Moreover, during the mining of the working face, the disturbance energy of the overburden stratum 1 is converted into electrical energy through the piezoelectric element 4, thereby converting the mechanical energy of the overburden stratum 1 into electrical energy, effectively reducing the degree of stress concentration, and achieving dual synergy of pressure relief and energy storage.

[0070] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are 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 understood as limiting the present 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 the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0072] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0073] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0074] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0075] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A coal mine roof deep hole hydraulic fracturing pressure relief energy storage and anti-scour method, characterized in that: include: Determining target strata for fracturing holes based on characteristics of overlying strata on a working face, wherein the working face is formed between two drifts; Drilling a fracturing hole in at least one of the two drifts to form a fracturing hole, wherein at least a portion of the fracturing hole is located in the target layer and extends along the extending direction of the drift; Performing hydraulic fracturing in the fracturing hole to fracture the target layer; A piezoelectric element is installed in the fracturing hole using a drilling rig, wherein the piezoelectric element is configured to deform under the squeezing action of the overburden to generate electrical energy; The electric energy generated by the piezoelectric element is reused.

2. The coal mine roof deep hole hydraulic fracturing pressure relief energy storage and anti-scour method according to claim 1, characterized in that: Drilling a fracturing hole in at least one of the two drifts comprises: Drilling a hole obliquely upward in the at least one drift along the extending direction of the drift using a drilling rig to form a deflection section of a fracturing hole, wherein the end point of the deflection section is located at the target layer; A drilling rig is used to drill a hole at the end point of the deflection section along the extension direction of the longitudinal channel to form a fracturing section of the fracturing hole, wherein the fracturing section and the deflection section are arranged in sequence in the extension direction of the fracturing hole, and the fracturing section is located at the target layer.

3. The coal mine roof deep hole hydraulic fracturing pressure relief energy storage and anti-scour method according to claim 2, characterized in that: The piezoelectric element is installed in the fracturing hole by using a drilling rig, comprising: Using a drilling rig, sequentially installing a plurality of first piezoelectric elements in the fracturing section of the fracturing hole, wherein the piezoelectric elements include 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; A plurality of the second piezoelectric components are sequentially installed in the deflection section of the fracturing hole using a drilling rig. The plurality of the second piezoelectric components are spaced apart in the extension direction of the deflection section and are electrically connected to the first piezoelectric component. The second piezoelectric components abut against the inner wall surface of the deflection section.

4. The coal mine roof deep hole hydraulic fracturing pressure relief energy storage and anti-scour method according to claim 3, characterized in that: The first piezoelectric element and the second piezoelectric element each include a piezoelectric body and a connecting portion, 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 to the piezoelectric body of the other of the two adjacent piezoelectric elements.

5. The coal mine roof deep hole hydraulic fracturing pressure relief energy storage and anti-scour method according to claim 4, characterized in that: On a projection plane perpendicular to the thickness direction of the piezoelectric body, the projection of the piezoelectric body is annular or sectoral, and the outer peripheral surface of the annular or sectoral abuts against the inner wall surface of the fracturing hole.

6. The coal mine roof deep hole hydraulic fracturing pressure relief energy storage and anti-scour method according to claim 3, characterized in that: The spacing distance between two adjacent piezoelectric elements among the first piezoelectric elements and the second piezoelectric elements is 0.5m-1m.

7. The coal mine roof deep hole hydraulic fracturing pressure relief energy storage and anti-scour method according to claim 3, characterized in that: The spacing distance between the plurality of first piezoelectric elements in the fracturing section is smaller than the spacing distance between the plurality of second piezoelectric elements in the deflection section.

8. The coal mine roof deep hole hydraulic fracturing pressure relief energy storage and anti-scour method according to claim 3, characterized in that: Also includes: A wire is used to electrically connect the second piezoelectric element to conduct the electrical energy from the piezoelectric element.

9. The coal mine roof deep hole hydraulic fracturing pressure relief energy storage and anti-scour method according to any one of claims 1 to 8, characterized in that: The fracturing holes include a first hole and a second hole, and the first hole and the second hole are spaced apart in the width direction of the longitudinal slot.

10. The coal mine roof deep hole hydraulic fracturing pressure relief energy storage and anti-scour method according to claim 9, characterized in that: The distance between the fracturing section of the first hole and the fracturing section of the second hole in the width direction of the trench is 50m-70m.

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