Hydraulic cutting seam pressure relief device and pressure relief method for roof of broken surrounding rock in coal mine roadway

Abstract

The present invention relates to the technical field of the stability control of mine roadway engineering, and discloses a hydraulic cutting seam pressure relief device and a pressure relief method for the broken surrounding rock roof of a coal mine roadway, including: a drilling structure for obliquely drilling holes from the roof of the roadway towards the surrounding rock above the roadway to form grouting and fracturing holes; a grouting structure arranged in the roadway and injecting slurry into the roof fracture development area above the roadway through the grouting and fracturing holes, so that the broken surrounding rock in the fracture development area is bonded together; and a hydraulic fracturing pressure relief structure arranged in the roadway and capable of extending into the grouting and fracturing holes to perform fracturing along the axial direction of the grouting and fracturing holes, so as to form cracks capable of cutting off the rock stratum of the roadway roof. The hydraulic cutting seam pressure relief device for the broken surrounding rock roof of the coal mine roadway has the advantage of effectively avoiding the collapse of the drilled holes before hydraulic fracturing.

Description

Technical Field

[0001] The present invention relates to the technical field of stable control of mine roadway engineering, and particularly to a hydraulic cutting seam pressure relief device and pressure relief method for the roof of broken surrounding rock in a coal mine roadway. Background Art

[0002] Mine roadways, especially the mining roadways, are underground passageways to ensure the safe and efficient mining of coal mines, and the stability of their surrounding rocks is closely related to the safe and efficient mining of coal mines.

[0003] Grouting for the surrounding rock of the roadway can densely fill the fissures in the surrounding rock of the roadway, playing a role in strengthening the broken surrounding rock. The hydraulic prefabricated cracks in the roof of the roadway can cut off the roof rock layer and make it lose the function of transmitting force, thereby relieving the roof pressure and playing a role in stabilizing and controlling the surrounding rock of the lower roadway.

[0004] In addition to being used for the mining of the current working face, some mining roadways will also be reserved as the mining roadways for the next working face. In this way, the mining roadways are often affected by the mining of the working face twice. High stress concentration areas will inevitably form above the roadway coal pillar and the solid coal, namely AγH and BγH (A>1; B>1). Affected by the high stress concentration areas AγH and BγH, the surrounding rock of the roadway often shows serious deformation and damage, that is, serious roof subsidence, rib spalling and floor heaving occur, as Figure 1 shown.

[0005] Due to the serious deformation and damage of the mining roadway, it seriously restricts the safe and efficient production of the working face. At this time, people often use the method of hydraulic prefabricated cracks to prefabricate cracks in the roof above the working face, so that the roof loses the function of transmitting force, and then reduce the high stress areas AγH and BγH of the roof to A’γH and B’γH (A’<A; B’<B), greatly reducing the deformation and damage of the surrounding rock of the mining roadway, as Figure 2 shown.

[0006] A key step in the hydraulic prefabricated crack technology is: drilling hydraulic fracturing holes into the roof in the mining roadway, and ensuring that the holes are complete and do not collapse. Since the mining roadway is excavated in advance of the working face, often several months or even longer in advance. Affected by the nature of the surrounding rock and high ground stress, fissures in the surrounding rock of the roadway are inevitably developed to form a fissure development area. When the hydraulic fracturing holes are drilled into the fissure development area of the roof rock layer, the phenomenon of hole collapse and blockage often occurs before the hydraulic prefabricated cracks can be carried out, as Figure 3 shown.

[0007] With the collapse of the hydraulic fracturing holes, the work of hydraulic prefabricated cracks will be interrupted, and drilling has to be re-done, which will not only seriously affect the construction progress and pressure relief quality, but also increase the input of manpower, material resources and financial resources, resulting in a significant increase in production costs. Summary of the Invention

[0008] (1) Technical problem to be solved

[0009] The object of the present invention is to provide a hydraulic cutting seam pressure relief device and method for the roof of broken surrounding rock in coal mine roadways, so as to solve the technical problem that in the prior art, affected by the properties of surrounding rock and high ground stress, fissures in the roadway surrounding rock are inevitably developed to form a fissure development area. When the hydraulic fracturing borehole is drilled in the fissure development area of the roof rock stratum, the phenomenon of borehole collapse and plugging often occurs before the hydraulic fracturing prefabricated cracks can be carried out, thus seriously affecting the construction progress and pressure relief quality.

[0010] (2) Technical solution

[0011] In order to solve the above technical problem, according to the first aspect of the present invention, there is provided a hydraulic cutting seam pressure relief device for the roof of broken surrounding rock in coal mine roadways, including: a drilling structure for obliquely drilling holes from the roof of the roadway towards the surrounding rock above the roadway to form grouting fracturing holes; a grouting structure arranged in the roadway and injecting slurry into the fissure development area of the roof above the roadway through the grouting fracturing holes, so that the broken surrounding rock in the fissure development area is bonded together; and a hydraulic fracturing pressure relief structure arranged in the roadway and capable of extending into the grouting fracturing holes to perform fracturing along the axial direction of the grouting fracturing holes to form cracks that can cut off the roof.

[0012] Among them, the grouting structure includes a grouting pump arranged in the roadway and a grouting pipe connected to the grouting pump and capable of extending into the grouting fracturing holes.

[0013] Among them, the grouting structure further includes a grouting borehole plugging device arranged in the grouting fracturing holes and close to the end of the roadway.

[0014] Among them, the grouting pipe includes a first-stage grouting pipe connected to the outlet of the grouting pump and a second-stage grouting pipe butt-connected and communicated with the first-stage grouting pipe and capable of extending into the grouting fracturing holes. Among them, the second-stage grouting pipe passes through the grouting borehole plugging device.

[0015] Among them, the hydraulic fracturing pressure relief structure includes a pressurized water pump arranged in the roadway and a water pipe group connected to the pressurized water pump and capable of extending into the grouting fracturing holes.

[0016] Among them, the hydraulic fracturing pressure relief structure further includes an upper hydraulic fracturing hole plugging device and a lower hydraulic fracturing hole plugging device arranged in the grouting fracturing holes. Among them, the upper hydraulic fracturing hole plugging device and the lower hydraulic fracturing hole plugging device are arranged at intervals along the axial direction of the grouting fracturing holes.

[0017] Among them, the water pipe group includes a first water pipe and a second water pipe which are arranged in the grouting and fracturing hole at intervals. The first end of the first water pipe is connected to the pressure pump, and the second end of the first water pipe passes through the lower hydraulic fracturing hole plugging device and extends into the upper hydraulic fracturing hole plugging device. An outlet hole is formed at the end of the first water pipe corresponding to the upper hydraulic fracturing hole plugging device. The first end of the second water pipe is connected to the pressure pump, and the second end of the second water pipe passes through the lower hydraulic fracturing hole plugging device and is located between the lower hydraulic fracturing hole plugging device and the upper hydraulic fracturing hole plugging device.

[0018] Among them, the grouting and fracturing hole includes a grouting hole and a hydraulic fracturing hole, and the center lines of the grouting hole and the hydraulic fracturing hole coincide.

[0019] According to the second aspect of the present invention, there is also provided a method for hydraulic cutting and pressure relief of the broken surrounding rock roof in a coal mine roadway, including: drilling a grouting hole in the fractured rock mass development area above the roadway; plugging the end of the grouting hole close to the roadway and injecting grout into the grouting hole; after the broken surrounding rock in the fractured rock mass development area is filled with grout and bonded together, drilling a hydraulic fracturing hole at the position of the roof corresponding to the grouting hole above the roadway; fracturing the hydraulic fracturing hole along the axial direction of the hydraulic fracturing hole to form a crack that cuts off the roof above the roadway.

[0020] Among them, the depth of the grouting hole is adapted to the fracture development depth of the broken surrounding rock in the fractured rock mass development area.

[0021] (III) Beneficial effects

[0022] The hydraulic cutting and pressure relief device for the broken surrounding rock roof in a coal mine roadway provided by the present invention has the following advantages compared with the prior art:

[0023] In this application, a grouting and fracturing hole is first constructed, and grout is injected into the fractured rock mass development area of the roof above the roadway through this grouting and fracturing hole, so that the broken surrounding rock in the fractured rock mass development area is bonded together, and fracturing is carried out along the axial direction of the grouting and fracturing hole to form a crack that can cut off the roof. It can be seen that in this application, the broken surrounding rock in the fractured rock mass development area above the roadway is first grouted and reinforced, and then fracturing is continued through the grouting and fracturing hole, overcoming the defect that the fracturing drill holes collapse on a large scale when fracturing the roof rock formation by the traditional hydraulic fracturing roof device. This application can greatly improve the stability of the hydraulic fracturing drill holes and significantly increase the success rate of hydraulic prefabricated cracks. In this way, not only the roof cutting and pressure relief effect is ensured, but also the investment in re-drilling is greatly reduced. Description of the drawings

[0024] Figure 1 It is a schematic diagram of the deformation and failure of the mining roadway under high stress in the prior art;

[0025] Figure 2 Schematic diagram of reducing the deformation of the roadway mined after prefabricating cracks in the roof in the prior art;

[0026] Figure 3 Schematic diagram of the collapse of a hydraulic fracturing borehole in a fissure development area in the prior art;

[0027] Figure 4 Schematic diagram of the structure for grouting of the hydraulic cutting seam pressure relief device for the broken surrounding rock roof of a coal mine roadway in an embodiment of the present invention;

[0028] Figure 5 Schematic diagram of the structure for hydraulic fracturing and forming cracks of the hydraulic cutting seam pressure relief device for the broken surrounding rock roof of a coal mine roadway in an embodiment of the present invention;

[0029] Figure 6 Schematic diagram of the step flow of the method for hydraulic cutting seam pressure relief of the broken surrounding rock roof of a coal mine roadway in an embodiment of the present invention.

[0030] Reference numerals:

[0031] 1: Borehole structure; 200: Roadway; 201: Top wall; 202: Roof; 20: Grouting and fracturing hole; 20a: Grouting hole; 20b: Hydraulic fracturing hole; 2: Grouting structure; 21: Grouting pump; 22: Grouting pipe; 221: First section of grouting pipe; 222: Second section of grouting pipe; 23: Grouting borehole plugging device; 203: Broken surrounding rock; 3: Hydraulic fracturing pressure relief structure; 31: Pressurized water pump; 32: Water pipe group; 321: First water pipe; 322: Second water pipe; 33: Upper hydraulic fracturing hole plugging device; 34: Lower hydraulic fracturing hole plugging device; 4: Crack. Detailed implementation manners

[0032] The following combines the drawings and embodiments to further describe in detail the specific implementation manners of the present invention. The following examples are used to illustrate the present invention but do not limit the scope of the present invention.

[0033] 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 to the present invention.

[0034] In addition, 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 quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0035] In the present invention, unless otherwise clearly defined and limited, the terms "mounted", "connected", "coupled", "fixed", etc. shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of 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 circumstances.

[0036] In the present invention, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0037] In the description of this specification, the description referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. means 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 can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0038] The above Figures 1 to 3 All are the attached drawings in the prior art, and the corresponding descriptions of this part of the attached drawings and the illustrated content have been given in the background art of the present invention. To avoid repetition, no detailed description will be given here.

[0039] Such as Figures 4 to 5As shown in the figure, the hydraulic cutting seam pressure relief device for the broken surrounding rock roof of the coal mine roadway schematically shows a drilling structure 1, a grouting structure 2, and a hydraulic fracturing pressure relief structure 3.

[0040] In an embodiment of the present application, the drilling structure 1 is used to obliquely drill holes from the top wall 201 of the roadway 200 towards the roof 202 above the roadway 200 to form grouting and fracturing holes 20.

[0041] The grouting structure 2 is arranged in the roadway 200 and injects slurry into the fracture development area of the roof 202 above the roadway 200 through the grouting and fracturing holes 20, so that the broken surrounding rock 203 in the fracture development area is bonded together.

[0042] The hydraulic fracturing pressure relief structure 3 is arranged in the roadway 200 and can extend into the grouting and fracturing holes 20 to perform fracturing along the axial direction of the grouting and fracturing holes 20 to form a crack 4 that can cut off the roof 202. Specifically, in the present application, the grouting and fracturing holes 20 are first constructed, and slurry is injected into the fracture development area of the roof 202 above the roadway 200 through the grouting and fracturing holes 20, so that the broken surrounding rock 203 in the fracture development area is bonded together, and fracturing is performed along the axial direction of the grouting and fracturing holes 20 to form a crack 4 that can cut off the roof 202. It can be seen that in the present application, by first grouting and reinforcing the broken surrounding rock 203 in the fracture development area above the roadway 200, and then continuing to construct and fracture through the grouting and fracturing holes 20, the defect that the fracturing drill holes collapse massively when fracturing the roof rock formation by the traditional hydraulic fracturing roof device is overcome. The present application can greatly improve the stability of the hydraulic fracturing drill holes and significantly increase the success rate of the hydraulic prefabricated cracks. In this way, not only the roof cutting and pressure relief effect is ensured, but also the investment in re-drilling is greatly reduced.

[0043] In an embodiment of the present application, the drilling structure 1 can be a surrounding rock drilling machine or other structures with drilling functions.

[0044] In an embodiment of the present application, the grouting structure 2 includes a grouting pump 21 arranged in the roadway 200 and a grouting pipe 22 connected to the grouting pump 21 and capable of extending into the grouting and fracturing holes 20. Among them, under the action of the power provided by the grouting pump 21, slurry is injected into the broken surrounding rock 203 in the fracture development area through the grouting pipe 22 and the grouting and fracturing holes 20. After the slurry fills the gaps between the broken surrounding rock 203 in the fracture development area, the broken surrounding rock 203 in the fracture development area will be bonded together.

[0045] In a preferred embodiment of the present application, the grouting structure 2 further includes a grouting borehole plugger 23 disposed in the grouting fracturing hole 20 and near the end of the tunnel 200. Specifically, the purpose of providing the grouting borehole plugger 23 is to effectively plug the grouting fracturing hole 20 near the end of the tunnel 200, thereby preventing the slurry from flowing into the tunnel 200 under the action of the gravity of the liquid when the slurry is injected into the grouting fracturing hole 20, and further preventing the slurry from blocking the tunnel 200.

[0046] like Figure 4 As shown, in a preferred embodiment of the present application, the grouting pipe 22 includes a first section grouting pipe 221 connected to the outlet of the grouting pump 21 and a second section grouting pipe 222 that is connected to the first section grouting pipe 221 and can extend into the grouting fracturing hole 20, wherein the second section grouting pipe 222 passes through the grouting borehole plugger 23. Specifically, the first section grouting pipe 221 is arranged in the tunnel 200 and is located outside the grouting fracturing hole 20, and the second section grouting pipe 222 is arranged in the grouting fracturing hole 20. After the grouting is completed, the second section grouting pipe 222 is separated from the first section grouting pipe 221, and the second section grouting pipe 222 is buried in the grouting fracturing hole 20 along with the slurry.

[0047] It should be noted that in order to ensure the sealing of the connection between the first section grouting pipe 221 and the second section grouting pipe 222, the end of the second section grouting pipe 222 close to the first section grouting pipe 221 can be inserted into the interior of the first section grouting pipe 221 for a certain length, so as to avoid leakage of slurry.

[0048] In one embodiment of the present application, the grouting drilling plugger 23 is similar to a hollow rubber plug, which is embedded in the grouting fracturing hole 20 in a wedge shape to prevent slurry leakage.

[0049] like Figure 5 As shown, in one embodiment of the present application, the hydraulic fracturing pressure relief structure 3 includes a pressurized water pump 31 disposed in the tunnel 200 and a water pipe assembly 32 connected to the pressurized water pump 31 and capable of extending into the grouting fracturing hole 20. Specifically, under the action of the pressurized water pump 31, the water in the water pipe assembly 32 is provided with a flow force, so that the water with a certain pressure in the water pipe assembly 32 can smoothly flow into the grouting fracturing hole 20 to complete the fracturing of the grouting fracturing hole 20, thereby generating a crack 4 on the roof above the tunnel 200 that can cut through the roof 202.

[0050] like Figure 5As shown, in an embodiment of the present application, the hydraulic fracturing pressure relief structure 3 further includes an upper hydraulic fracturing hole plug 33 and a lower hydraulic fracturing hole plug 34 disposed in the grouting fracturing hole 20. Among them, the upper hydraulic fracturing hole plug 33 and the lower hydraulic fracturing hole plug 34 are arranged at intervals along the axial direction of the grouting fracturing hole 20. Specifically, after grouting, when the gaps between the broken surrounding rocks 203 in the fracture development area are filled with grout and the broken surrounding rocks 203 in the fracture development area are bonded together, the grouting fracturing hole 20 can be fractured. Before fracturing, it is necessary to use the upper hydraulic fracturing hole plug 33 and the lower hydraulic fracturing hole plug 34 to block the part of the grouting fracturing hole 20 far from the roadway 200 in advance, and then inject water into the blocked section to achieve fracturing. Then, gradually move the upper hydraulic fracturing hole plug 33 and the lower hydraulic fracturing hole plug 34 towards the direction close to the roadway 200 to perform fracturing again at a suitable position, and repeat in sequence until the fracturing of the end of the grouting fracturing hole 20 close to the roadway 200 is completed, and then stop fracturing.

[0051] It can be understood that in order to achieve fracturing, a plurality of small holes need to be constructed on the hole wall of the grouting fracturing hole 20 so as to achieve the fracturing of the fracturing part on the grouting fracturing hole 20 under the action of internal water pressure.

[0052] As Figure 5 shown, in a preferred embodiment of the present application, the water pipe group 32 includes a first water pipe 321 and a second water pipe 322 disposed in the grouting fracturing hole 20 and arranged at intervals. Among them, the first end of the first water pipe 321 is connected to the pressure pump 31, the second end of the first water pipe 321 passes through the lower hydraulic fracturing hole plug 34 and extends into the upper hydraulic fracturing hole plug 33, and a water outlet hole is formed at the end of the first water pipe 321 corresponding to the upper hydraulic fracturing hole plug 33.

[0053] The first end of the second water pipe 322 is connected to the pressure pump 31, and the second end of the second water pipe 322 passes through the lower hydraulic fracturing hole plug 34 and is located between the lower hydraulic fracturing hole plug 34 and the upper hydraulic fracturing hole plug 33. Specifically, a water outlet hole (not shown in the figure) is formed at the end of the first water pipe 321 corresponding to the upper hydraulic fracturing hole plug 33. Under the action of a certain pressure, water will be sprayed into the interior of the upper hydraulic fracturing hole plug 33 through the water outlet hole, so that the upper hydraulic fracturing hole plug 33 expands radially under the action of water pressure, thereby achieving the purpose of blocking the grouting fracturing hole 20.

[0054] It should be noted that the pressure pump 31 can provide high-pressure water not less than 30 MPa (megapascals), and the required power supply voltage is 660 / 1140 V (volts), which is consistent with the underground power supply high voltage.

[0055] The number of the water outlet holes can be multiple and they are arranged at intervals along the circumference of the first water pipe 321 corresponding to the end of the upper hydraulic fracturing sealer 33.

[0056] By continuously discharging water from the end of the second water pipe 322 between the upper hydraulic fracturing sealer 33 and the lower hydraulic fracturing sealer 34 , the grouting fracturing hole 20 can be fractured as the water pressure accumulates.

[0057] In one embodiment of the present application, the grouting and fracturing hole 20 includes a grouting hole 20a and a hydraulic fracturing hole 20b, wherein the center lines of the grouting hole 20a and the hydraulic fracturing hole 20b coincide with each other. Specifically, after grouting is completed, the grouting hole 20a is blocked. When hydraulic fracturing is required, the hydraulic fracturing hole 20b can be drilled again in the location of the grouting hole 20a. This can greatly reduce the drilling workload, shorten the construction process, and improve drilling efficiency.

[0058] like Figure 6 According to a second aspect of the present invention, a method for hydraulically cutting and unloading pressure on the broken surrounding rock roof of a coal mine tunnel is provided, comprising:

[0059] Step S1 : drilling grouting holes 20 a in the crack development area of the roof 202 above the tunnel 200 .

[0060] In step S2, the end of the grouting hole 20a near the roadway 200 is sealed and grouting is performed into the grouting hole 20a. Specifically, the mixed slurry is poured into the grouting pump 21 and stirred thoroughly. Then, the slurry is injected into the gaps in the broken surrounding rock 203 through the grouting pump 21 until all gaps in the broken surrounding rock 203 are filled, and then the grouting operation is stopped.

[0061] In step S3, after the broken surrounding rock 203 in the fracture development zone is filled with grout and bonded together, a hydraulic fracturing hole 20b is drilled in the roof 202 above the tunnel 200 at a location corresponding to the grouting hole 20a. The centerline of the grouting hole 20a coincides with the centerline of the hydraulic fracturing hole 20b.

[0062] In step S4, the hydraulic fracturing hole 20b is fractured along its axial direction to form a crack 4 that cuts through the roof 202 above the roadway 200. After the crushed surrounding rock 203 is reinforced by grouting, the upper and lower hydraulic fracturing sealers 33 and 34 separate the hydraulic fracturing hole 20b into a fracturing space. The pressurized water pump 31 is then activated to inject high-pressure water through the first and second water pipes 321 and 322, thereby preforming the aforementioned crack 4 in the hole wall.

[0063] It should be noted that when fracturing the hydraulic fracturing hole 20b, the time for introducing high-pressure water is not less than 30 minutes.

[0064] Repeat the above steps S1 to S4 to perform staged fracturing on the hydraulic fracturing hole 20b. Stop the fracturing of the hydraulic fracturing hole 20b until all fracturing along the axial direction of the hydraulic fracturing hole 20b is completed.

[0065] In an embodiment of the present application, the depth of the grouting hole 20a is adapted to the depth of the fissure development in the broken surrounding rock 203 in the fissure development area. In this way, it can ensure that the grouting slurry can be evenly diffused within the grouting hole 20a.

[0066] In summary, the present application first constructs the grouting fracturing hole 20, injects slurry into the fissure development area of the roof 202 above the roadway 200 through the grouting fracturing hole 20, so that the broken surrounding rock 203 in the fissure development area is bonded into one body, and fracturing is carried out along the axial direction of the grouting fracturing hole 20 to form a crack 4 that can cut off the roof 202. It can be seen that the present application overcomes the defect of large-scale collapse of the fracturing borehole during roof fracturing by the traditional hydraulic fracturing roof device by first grouting and strengthening the broken surrounding rock 203 in the fissure development area above the roadway 200, and then continuing to construct and fracture through the grouting fracturing hole 20. The present application can greatly improve the stability of the hydraulic fracturing borehole and significantly increase the success rate of hydraulic prefabricated cracks. In this way, it not only ensures the roof cutting and pressure relief effect, but also greatly reduces the investment in re-drilling.

[0067] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A hydraulic cutting and pressure relief device for the broken surrounding rock roof of a coal mine tunnel, characterized in that: include: A drilling structure is used to drill holes obliquely from the top plate of the roadway toward the surrounding rock above the roadway to form grouting and fracturing holes; the grouting and fracturing holes include grouting holes and hydraulic fracturing holes, wherein the center lines of the grouting holes coincide with the center lines of the hydraulic fracturing holes; A grouting structure is provided in the roadway and injects slurry into the crack development area of the roof above the roadway through the grouting fracturing holes, so as to bond the broken surrounding rocks in the crack development area into one; and A hydraulic fracturing pressure relief structure is arranged in the tunnel and can extend into the grouting fracturing hole, and performs fracturing along the axial direction of the grouting fracturing hole to form a crack that can cut through the roof rock layer; The hydraulic fracturing pressure relief structure includes a pressure water pump arranged in the tunnel and a water pipe group connected to the pressure water pump and capable of extending into the grouting fracturing hole; It also includes an upper hydraulic fracturing sealer and a lower hydraulic fracturing sealer disposed in the grouting fracturing hole, wherein the upper hydraulic fracturing sealer and the lower hydraulic fracturing sealer are spaced apart along the axial direction of the grouting fracturing hole; The water pipe group includes a first water pipe and a second water pipe arranged in the grouting fracturing hole and arranged at intervals, wherein the first end of the first water pipe is connected to the pressurized water pump, the second end of the first water pipe passes through the lower hydraulic fracturing sealer and extends into the upper hydraulic fracturing sealer, and a water outlet is constructed at the end of the first water pipe corresponding to the upper hydraulic fracturing sealer; The first end of the second water pipe is connected to the pressurized water pump, and the second end of the second water pipe passes through the lower hydraulic fracturing sealer and is located between the lower hydraulic fracturing sealer and the upper hydraulic fracturing sealer.

2. The hydraulic cutting and pressure relief device for the broken surrounding rock roof of a coal mine tunnel according to claim 1 is characterized in that: The grouting structure comprises a grouting pump arranged in the tunnel and a grouting pipe connected to the grouting pump and capable of extending into the grouting fracturing hole.

3. The hydraulic cutting and pressure relief device for the broken surrounding rock roof of a coal mine tunnel according to claim 2 is characterized in that: The grouting structure further includes a grouting borehole plugger disposed in the grouting fracturing hole and close to the end of the tunnel.

4. The hydraulic cutting and pressure relief device for the broken surrounding rock roof of a coal mine tunnel according to claim 3 is characterized in that: The grouting pipe includes a first section of grouting pipe connected to the outlet of the grouting pump and a second section of grouting pipe connected to the first section of grouting pipe and capable of extending into the grouting fracturing hole, wherein the second section of grouting pipe passes through the grouting borehole plugger.

5. A method for hydraulically cutting and unloading pressure on the broken surrounding rock roof of a coal mine tunnel, using the hydraulically cutting and unloading pressure device for the broken surrounding rock roof of a coal mine tunnel according to any one of claims 1 to 4, characterized in that: Includes: Drill grouting holes in the area where cracks develop in the roof above the roadway; The end of the grouting hole close to the roadway is sealed and grouting is performed into the grouting hole; After the broken surrounding rocks in the fracture development area are filled with grout and bonded together, hydraulic fracturing holes are drilled in the roof above the tunnel at locations corresponding to the grouting holes; The hydraulic fracturing hole is fractured along its axial direction to form a crack that cuts off the roof above the tunnel.

6. The hydraulic cutting and pressure relief method for the broken surrounding rock roof of a coal mine tunnel according to claim 5 is characterized in that: The depth of the grouting hole is adapted to the depth of the fracture development of the broken surrounding rock in the fracture development zone.

Images