Roof cutting and pressure relief supporting structure and method for gob-side roadway

Abstract

The invention provides a gob-side roadway roof cutting pressure relief supporting structure and method, and belongs to the technical field of coal mining construction. And the inclined coal seam roof-cutting pressure-relief coal-pillar-free asymmetric roadway support is realized. According to the technical scheme, the system comprises a gob-side roadway formed along the inclined coal seam and an anchor net beam grouting comprehensive supporting system arranged on the gob-side roadway; and a waste rock blocking device is arranged in the gob-side roadway. The method has the beneficial effects that after the holes are drilled in the rock stratum, the pulse waves are used for conducting directional fracturing on the rock stratum, the kerfs are formed between the adjacent drill holes, directional cutting of the basic roof and the immediate roof of the gob-side entry retaining is achieved, after working face recovery, the basic roof is subjected to shear fracture in the pre-splitting kerfs, the length of a lateral cantilever is reduced, and pressure relief is completed. And meanwhile, for a fracture surface which is seriously impacted by roof crushing and goaf gangue tumbling, a composite supporting system is formed in a way of filling high-water materials beside a roadway and bolting-grouting supporting in combination with early-stage anchor net cable supporting.

Description

Technical Field

[0001] The invention relates to the technical field of coal mining construction, and in particular to a top cutting and pressure relief support structure and a support method for a goaf-side tunnel. Background Art

[0002] In order to recover more coal resources, increase the recovery rate of underground coal resources, reduce the high bearing pressure caused by wide coal pillars on adjacent coal seams and floor tunnels, and reduce the occurrence of rock burst, gob-side tunneling and gob-side tunneling have become the common layout methods for longwall mining in coal mines. Gob-side tunneling in my country mainly uses narrow coal pillars to protect the tunnel, that is, a 3-5m wide coal pillar is retained between the tunnel and the goaf. The narrow coal pillar not only deforms the surrounding rock strongly during tunneling, but also needs to withstand the impact of mining twice during mining. The roof sinks strongly and the floor bulges seriously, requiring multiple repairs before normal use. The gob-side tunneling without coal pillars is not affected by coal pillars. The tunnel is arranged in the support pressure reduction area near the goaf, which guarantees the cost and safety of tunnel support. At the same time, compared with gob-side tunneling, there is no need to dig tunnels, which reduces the excavation cost and alleviates the tense situation of mining and excavation succession.

[0003] Gob-side tunneling places higher demands on the support method, because the basic top rock blocks cause a large amount of sinking of the gob-side tunnel roof during the rotation and sinking process. The measures usually taken are gob filling and top cutting pressure relief technology. At present, gob-side tunneling without coal pillars is mainly used in nearly horizontal tunnels. Traditional roadside supports include wood piles, dense pillars, gangue belts, and concrete blocks. After the mining of inclined coal seams, after the direct roof collapses in the inclined direction, the gangue rolls or slides along the inclined direction of the working face, and accumulates at the bottom of the working face, which is easy to enter the tunnel. At the same time, the old roof bends and sinks until it breaks, which will cause severe deformation of the coal side of the gob-side tunnel and the roadside support body. When conventional support methods such as ordinary supports, anchor rods, and anchor net cables are used, the direct roof is prone to dislocation between layers, and it is difficult to control the deformation and damage of the roof. These problems have brought great difficulties to gob-side tunneling in inclined coal seams.

[0004] How to solve the above technical problems is the subject faced by the present invention. Summary of the invention

[0005] The purpose of the present invention is to provide a roof cutting and pressure relief support structure and support method along an empty tunnel, which solves the problem that after the inclined coal seam is mined, the direct roof collapses along the inclined direction, and the gangue rolls or slides along the inclined direction of the working face, and accumulates at the bottom of the working face.

[0006] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention is specifically: a gob-side tunnel top cutting and pressure relief support structure, including a gob-side tunnel opened along the inclined coal seam, and an anchor-net-beam-grouting comprehensive support system arranged on the gob-side tunnel;

[0007] The anchor-grid-beam-grouting comprehensive support system includes an anchor rod and cable support structure arranged on the roof and two sides of the goaf-side tunnel, a reinforced support provided by grouting anchor rods and grouting anchor cables, and a steel beam erected on the roof;

[0008] A rock retaining device is arranged in the gob-side tunnel.

[0009] The anchor rod and anchor cable support structure comprises a mining anchor rod and a mining anchor cable;

[0010] The mining anchor is provided with a metal mesh;

[0011] The metal mesh is covered on the roof of the gob-side tunnel to form an anchor mesh;

[0012] The mining anchor cables are symmetrically arranged along the center line on the left and right sides of the gob tunnel.

[0013] The rock-blocking device comprises a single pillar, a double-layer metal mesh and a flexible mold bag, wherein the double-layer metal mesh is fixed on a side of the single pillar close to the goaf, the flexible mold bag is arranged inside the double-layer metal mesh, and high-water filling material is injected into the flexible mold bag to seal the goaf;

[0014] The single prop adopts a hydraulic prop.

[0015] A top cutting drill hole is provided on the top plate of the gob-side tunnel, and the top cutting drill hole is directly drilled into the interior of the basic top;

[0016] A pulse device is arranged below the top cutting drill hole, and the pulse device comprises a hole sealer, a push rod and a pulse generator, and a water injection port is arranged below the hole sealer.

[0017] The roof of the gob-side tunnel has an inclination angle the same as that of the coal seam, and the bottom rock layer is horizontally excavated.

[0018] It also includes a reinforcement device, which includes a reinforcement rod arranged at the top of the single pillar, a clamp assembly arranged at the bottom of the single pillar and on the reinforcement rod, a connecting rod is arranged between the clamp assemblies at the bottom of adjacent single pillars, and a connecting rod is arranged between the clamp assembly at the bottom of the single pillar and the clamp assembly on the reinforcement rod at the top of the adjacent single pillar;

[0019] The clamp assembly comprises two semi-annular clamps, both ends of which are provided with ear plates, and the ear plates of the two clamps are fixedly connected by bolts;

[0020] An upper and lower horizontal plate are arranged on the outer wall of the clamp, a connecting block is arranged between the upper and lower horizontal plates, vertical threaded holes are opened on the upper and lower horizontal plates and one end of the connecting block, and the upper and lower horizontal plates are fixedly connected with one end of the connecting block by bolts;

[0021] The other end of the connecting block is provided with two left and right vertical plates, the vertical plates are provided with transverse threaded holes, the connecting rod is connected between the left and right vertical plates, both ends of the connecting rod are provided with threaded holes, and the left and right vertical plates are fixedly connected to the ends of the connecting rod by bolts;

[0022] An annular limiting groove is provided on the opposite side walls of the left and right vertical plates, and the inner diameter of the limiting groove is larger than the diameter of the threaded hole;

[0023] Limiting rings are arranged on both sides of the end of the connecting rod, and the limiting rings are slidably matched with the limiting grooves;

[0024] A connecting plate is provided at the top of the single pillar, and connecting plates are provided at the top and bottom of the reinforcement rod. Threaded holes are provided on the connecting plates, and the connecting plate at the top of the single pillar and the connecting plate at the bottom of the reinforcement rod are fixedly connected by bolts.

[0025] A supporting method for a gob-side tunnel top cutting pressure relief supporting structure comprises the following steps:

[0026] Step (1) Basic support:

[0027] The goaf-side tunnel is excavated along the inclined coal seam, and the anchor rod and cable support structure is set on the roof and both sides of the goaf-side tunnel, and a metal net is set on the mining anchor to cover the roof of the goaf-side tunnel, forming an anchor net;

[0028] Step (2):

[0029] Single pillars are set up on the lower and upper walls of the gob-side tunnel in front of the coal mining working face to support the roof of the gob-side tunnel, and a rock blocking device is set up;

[0030] Step (3):

[0031] Before the coal mining face is mined, multiple top cutting drill holes are opened in the rock layer at equal intervals along the extension direction of the empty roadway. The top cutting drill holes extend obliquely from the direct top to the inside of the basic top at its upper end, and pulse wave hydraulic top cutting and pressure relief are performed;

[0032] Step (4):

[0033] Strengthen support: Strengthen support through grouting anchor rods and grouting anchor cables, set up steel beams on the top plate, form an anchor-net-beam-grouting comprehensive support system, and improve the supporting capacity of surrounding rock;

[0034] Step (5):

[0035] Temporary support is removed behind the coal mining working face, and a rock retaining device is left to pile up the collapsed rocks on the upper side of the goaf to the lower side of the goaf to form natural support.

[0036] Step (6):

[0037] After the working face is mined, the gob-side tunnels are gradually stabilized, the gob area is closed, and the remaining tunnels are completed;

[0038] Step (7):

[0039] Repeat steps (1) to (6) to complete the top cutting and pressure relief of the entire tunnel and the non-coal pillar asymmetric tunnel support work.

[0040] In step (4), the length of the grouting anchor rod and the grouting anchor cable is determined comprehensively according to the direct roof and basic roof height of the tunnel and the inclination of the coal seam. A grouting anchor cable with a length of 6.3m and a grouting anchor rod with a length of 3.0m are selected, and a mining anchor cable with a length of 4.1m is selected for the solid coal side.

[0041] In step (3), the top cutting pressure relief is a pulse-driven water flow fracturing method, which is achieved by opening multiple top cutting boreholes in the rock formation, injecting water into the top cutting boreholes from the water injection port, starting the pulse transmitter to emit pulse waves, and adjusting the angle so that the pulse waves break the surrounding rock along the direction of the tunnel, gradually forming cracks.

[0042] In step (2), the rock-blocking device is used in combination with high-water-filled materials and single pillars. A single pillar is set in the coal mining working face near the goaf to support the roof of the coal mining working face. Soft mold bags are used to fill the high-water-filled materials along the side of the goaf. Anchor rods and grouting anchor cables are driven into the goaf side and roof of the goaf, and steel mesh is hung on the anchor rods to block rock.

[0043] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention realizes directional cutting of the basic roof and direct roof of the gob-side roadway by using pulse waves to directionally fracture the rock formation after drilling holes in the rock formation, and forms cuts between adjacent boreholes. After the working face is mined, the basic roof is sheared and broken at the pre-cracked cuts, which reduces the lateral cantilever length and completes the pressure relief. At the same time, for the sections with broken roofs and severe impacts of gangue rolling down in the gob area, a composite support system is formed by filling high-water materials and anchoring support beside the roadway, combined with the previous anchor net cable support, to realize the inclined coal seam top cutting and pressure relief and non-coal pillar asymmetric roadway support. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.

[0045] Figure 1 This is a schematic diagram of the coal seam occurrence after tunnel excavation according to an embodiment of the present invention.

[0046] Figure 2 It is a schematic diagram of top cutting and pressure relief of the working face mining roof in an embodiment of the present invention.

[0047] Figure 3 It is a schematic diagram of comprehensive tunnel support parameters according to an embodiment of the present invention.

[0048] Figure 4 It is a schematic diagram of the overall structure of the reinforcement device according to an embodiment of the present invention.

[0049] Figure 5 for Figure 4 A partial enlarged view of point A.

[0050] Figure 6 It is a structural schematic diagram of a connecting block according to an embodiment of the present invention.

[0051] Figure 7 It is a schematic diagram of the local structure of the end of the connecting rod according to an embodiment of the present invention.

[0052] Among them, the figure markings are: 1. coal seam; 2. direct roof; 3. basic roof; 4. tunnel along the goaf; 5. bottom rock layer; 6. working face to be mined; 7. single pillar; 8. top cutting drill hole; 9. goaf; 10. flexible mold bag; 11. mining anchor cable; 12. grouting anchor cable; 13. mining anchor rod; 15. reinforcement rod; 16. connecting rod; 17. clamp; 18. horizontal plate; 19. connecting block; 20. vertical plate; 21. limit groove; 22. limit ring; 23. connecting plate. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. Of course, the specific embodiments described here are only used to explain the present invention and are not used to limit the present invention.

[0054] Example 1

[0055] See also Figures 1 to 3 The present invention provides a technical solution of a gob-side tunnel top cutting pressure relief support structure, comprising a gob-side tunnel 4 opened along an inclined coal seam 1, and an anchor-net-beam-grouting comprehensive support system arranged on the gob-side tunnel 4;

[0056] The anchor-net-beam-grouting integrated support system includes an anchor rod and cable support structure arranged on the roof and two sides of the gob-side tunnel 4, a reinforced support provided by grouting anchor rods and grouting anchor cables 12, and a steel beam erected on the roof;

[0057] A rock retaining device is provided in the gob-side tunnel 4.

[0058] The anchor rod and anchor cable support structure includes a mining anchor rod 13 and a mining anchor cable 11;

[0059] A metal mesh is provided on the mining anchor 13;

[0060] The metal mesh is covered on the roof of the gob-side tunnel 4 to form an anchor mesh;

[0061] The mining anchor cables 11 are symmetrically arranged along the center line of the left and right sides of the gob tunnel 4 .

[0062] The rock-blocking device comprises a single support 7, a double-layer metal mesh and a flexible mold bag 10. The double-layer metal mesh is fixed on one side of the single support 7 close to the goaf 9. The flexible mold bag 10 is arranged in the double-layer metal mesh. High-water filling material is injected into the flexible mold bag 10 to seal the goaf 9.

[0063] The single support 7 adopts a hydraulic support.

[0064] A top cutting drill hole 8 is opened on the top plate of the gob-side tunnel 4, and the top cutting drill hole 8 is drilled into the interior of the basic top 3 through the direct top 2;

[0065] A pulse device is arranged below the top drilling hole 8, the pulse device comprises a hole sealer, a push rod and a pulse generator, and a water injection port is arranged below the hole sealer.

[0066] The inclination angle of the roof of the gob-side tunnel 4 is the same as that of the coal seam 1, and the bottom rock layer 5 is horizontally excavated.

[0067] A support method based on an inclined coal seam top cutting and pressure relief non-coal pillar asymmetric tunnel support structure comprises the following steps:

[0068] (1) Basic support: A tunnel 4 is excavated along the inclined coal seam, with a tunnel width of 5.4m and a tunnel centerline height of 3.4m. The tunnel roof has the same inclination angle of 20° as the coal seam 1, and the bottom rock layer 5 is horizontally excavated. The support method is that the tunnel roof is supported by mining anchors 13 and mining anchor cables 11, and a metal mesh is set on the anchors. The spacing between the anchors is 800mm*800mm and the length is 3m. Left-handed threaded steel anchors with a diameter of 22mm are used. The anchor cables are arranged symmetrically along the left and right sides of the tunnel centerline, with a diameter of 22mm, a length of 6300mm, a spacing of 800*1600mm, and a tray specification of 300*300*16mm. One strike anchor cable beam is added at the top and both sides of the tunnel. The anchor cable has a diameter of 22mm, L=6300, and a spacing of 1900(1700)*1600mm. The beam uses 14# channel steel, L=3600mm. The strike anchor cable beam anchor cables and single anchor cables are arranged alternately to form a "323" anchor cable arrangement. If the rock properties of the top plate change, the anchor cable length should be adjusted accordingly to ensure that the anchor cable is rooted in the stable rock layer for no less than 1.2m.

[0069] Of course, the reinforcement support methods for the roof and the two sides are not limited to the above-mentioned specific forms, and can be specifically designed according to the rock structure and mining parameters.

[0070] (2) The rock-blocking device includes a single support 7, a double-layer metal mesh and a flexible mold bag 10. The double-layer metal mesh is fixed to one side of the single support 7 close to the goaf 9. The flexible mold bag 10 is laid in the double-layer metal mesh. After the tunnel is stable, high-water material is added to the flexible mold bag 10 to seal the goaf 9.

[0071] (3) Grouting reinforcement: Anchoring devices are used in conjunction with the upper, middle and lower anchor cables of the vertical anchor beam. Constant resistance anchor cables and grouting anchor cables 12 are used for reinforcement support. Ordinary anchor cables are used for support on the solid coal side, and grouting anchor cables are used for support on the goaf side and roof. The anchoring devices are arranged in a "212" pattern with a spacing of 2400mm*1600mm, forming a grouting "five-flower arrangement". The specific gravity of the grouting liquid is 1.3; grouting is stopped when the grouting pressure reaches 1.5MPa. If it is found that there is no grouting pressure, the grouting volume is controlled.

[0072] (4) The reinforcement anchor cables are arranged in a "212" pattern, that is, 2 and 1 single anchor cables are arranged alternately for every 2 rows of anchor rods. The positions of 2 anchor cables are 700mm and 2300mm from the top plate respectively, and the position of 1 anchor cable is 1500mm from the top plate. The anchor cable specifications are 22mm in diameter, L=4100mm, and vertical coal wall construction; the first anchor on the anchor steel belt is changed to a reinforcement anchor cable, and the others are selected with an anchor cable diameter of 22mm, L=3000mm, and a row spacing of 800*800mm. The top anchor follows the head closely, and the side anchor shall not lag behind the head by more than 1 cycle. The specifications of the anchor tray are: 150*150*10mm; the anchor torque: not less than 300N·m for rock and not less than 200N·m for coal; the anchoring force of the anchor: not less than 127KN; the anchor angle: perpendicular to the rock surface, the angle between the two shoulder anchors on the top and the normal of the roof is 10°, the angle between the shoulder anchors on the side and the normal of the side is 10°, and the exposed thread of the anchor is 10~50mm.

[0073] (5) Pulse hydraulic drilling fracturing method: a cutting hole 8 is opened from the tunnel roof. The drilling angle and depth are determined comprehensively according to the coal seam inclination and the rock layer. It is required to drill the hole into the basic roof 3 to achieve a good cutting fracturing effect. The drilling angle is generally 60-75°, and the drilling depth can generally reach 10-15m.

[0074] First, a pulse device is installed below the borehole, including a sealer, a push rod and a pulse generator. A water injection port is set below the sealer, and water is injected into the borehole through the water injection port. Then the pulse starter is started to generate pulse waves on both sides of the borehole. Low-pressure water extends forward along the generated cracks, and the push rod moves toward the hole mouth to change the fracture position, forming a certain direction of cracks in the basic top 3 rock layer. The water pressure is controlled at about 0.5MPa, the pulse wave crushing radius is 1m, and the push rod shrinks 0.8-1m each time.

[0075] (6) After the working face is mined, single pillars are promptly arranged for temporary support. The basic top 3 of the goaf collapses along the structural surface of the prefabricated cut to form the roadway wall. After sufficient compaction, the single pillars are gradually withdrawn, and the side walls of the goaf are sprayed.

[0076] The present invention performs pulse hydraulic fracturing in the basic top rock layer by drilling holes, and breaks and collapses in time after the working face is mined, thereby reducing the lateral span of the basic top, and the fracture line is located obliquely above the goaf-side reserved lane, reducing the stress concentration in the lane area. At the same time, through comprehensive support means such as lane anchors, anchor cables, steel beams, metal meshes, and grouting, the sinking of the lane roof and the deformation of the side are controlled in all directions. The entire operation process is safe, controllable, and easy to operate. It is suitable for the operating environment of high-gas mines and ensures safe and efficient production.

[0077] Example 2

[0078] See also Figures 4 to 7 , on the basis of embodiment 1, further comprising a reinforcement device, the reinforcement device comprising a reinforcement rod 15 arranged at the top of the single pillar 7, a clamp assembly arranged at the bottom of the single pillar 7 and on the reinforcement rod 15, a connecting rod 16 is arranged between the clamp assemblies at the bottom of adjacent single pillars 7, and a connecting rod 16 is arranged between the clamp assembly at the bottom of the single pillar 7 and the clamp assembly on the reinforcement rod 15 at the top of the adjacent single pillar 7;

[0079] The clamp assembly includes two semi-annular clamps 17, with ear plates provided at both ends of the clamps 17, and the ear plates of the two clamps 17 are fixedly connected by bolts;

[0080] An upper and lower horizontal plate 18 is provided on the outer wall of the clamp 17, and a connecting block 19 is provided between the upper and lower horizontal plates 18. Vertical threaded holes are provided on the upper and lower horizontal plates 18 and one end of the connecting block 19, and the upper and lower horizontal plates 18 and one end of the connecting block 19 are fixedly connected by bolts;

[0081] The other end of the connecting block 19 is provided with two left and right vertical plates 20, and the vertical plates 20 are provided with transverse threaded holes. The connecting rod 16 is connected between the left and right vertical plates 20, and both ends of the connecting rod 16 are provided with threaded holes. The left and right vertical plates 20 are fixedly connected to the ends of the connecting rod 16 by bolts.

[0082] An annular limiting groove 21 is provided on the opposite side walls of the left and right vertical plates 20, and the inner diameter of the limiting groove 21 is larger than the diameter of the threaded hole;

[0083] Limiting rings 22 are provided on both sides of the end of the connecting rod 16 , and the limiting rings 22 are slidably matched with the limiting grooves 21 .

[0084] When in use, first fix the reinforcing rod 15 to the top of the single column 7, then connect the clamp assembly at the bottom of the single column 7, clamp the two semi-annular clamps 17 on the outer wall of the bottom of the single column 7, and then fix them with bolts; then fix the upper and lower horizontal plates 18 and one end of the connecting block 19 by bolts, and then connect the left and right vertical plates 20 and the ends of the connecting rod 16 by bolts. Do not tighten them completely at first to ensure the adjustment margin, and then connect the clamp assembly on the reinforcing rod 15, and then fix the upper and lower horizontal plates 18 and one end of the connecting block 19 by bolts, and then connect the left and right vertical plates 20 and the ends of the connecting rod 16 by bolts. After adjusting the connecting rod 16, you can tighten and fix one end of the connecting rod 16 with the left and right vertical plates 20 connected to the bottom of the single column 7 by bolts, and the other end of the connecting rod 16 with the left and right vertical plates 20 connected to the reinforcing rod 15 by bolts.

[0085] Similarly, the clamp assembly may be connected to the reinforcement rod 15 first, and then the clamp assembly may be connected to the reinforcement rod 15 after the connection rod 16 is adjusted.

[0086] Likewise, connecting rods 16 are also provided between the bottoms of adjacent single pillars 7 for connection and fixation.

[0087] A connecting rod 16 is connected between the clamp assemblies at the bottom of adjacent single pillars 7, and the direction of the connecting rod 16 is transverse. A connecting rod 16 is connected between the clamp assemblies at the bottom of the single pillar 7 and the clamp assemblies on the reinforcing rods 15 at the top of the adjacent single pillar 7, and the direction of the connecting rod 16 is oblique. In this way, a triangular structure is formed between the transverse connecting rod 16, the oblique connecting rod 16 and the single pillar 7.

[0088] The help of the triangular structure to the stability of the roadway is mainly reflected in the following aspects:

[0089] Improve the overall stability of the support structure: The triangular structure has the characteristics of good stability, can effectively disperse and bear the ground pressure, reduce the overall deformation and displacement of the support structure, and improve the stability of the tunnel.

[0090] Enhance the rigidity and strength of the support structure: The triangular structure formed by the transverse and oblique connecting rods can effectively enhance the rigidity and strength of the support structure, improve its tensile and compressive resistance, and reduce the risk of structural deformation and damage.

[0091] Improve support effect: The triangular structure can effectively prevent local instability and local damage of the support structure, improve the support effect, extend the service life of the support structure, and reduce maintenance and repair costs.

[0092] Therefore, the formation of a triangular structure can effectively improve the stability of the tunnel and ensure the safety and continuous operation of the tunnel project.

[0093] The reinforcement device has a simple structure and is easy to install. Since the reinforcement device adopts a clamp combination and a connecting rod structure, the installation process is simpler and faster, and no special tools and equipment are required.

[0094] The reinforcement device has good stability and reliability. Through the fixing of the clamp 17 and the adjustment of the connecting rod 16, the stability and bearing capacity of the single pillar 7 can be effectively enhanced to ensure the safety of the overall structure.

[0095] The reinforcement device has a certain degree of adjustability. The design of the connecting rod 16 allows a certain degree of adjustment to accommodate the size differences between different single pillars, making the reinforcement effect more perfect.

[0096] The reinforcement device can be reused. Due to the bolt connection method, it can be easily disassembled and reused, saving costs and reducing resource waste.

[0097] The reinforcement device has good applicability. It is suitable for single pillars of different shapes and materials and has strong versatility and applicability.

[0098] Example 3

[0099] See also Figures 4 to 7 On the basis of Example 2, a connecting plate 23 is provided at the top of the single pillar 7, and connecting plates 23 are provided at the top and bottom of the reinforcement rod 15. Threaded holes are provided on the connecting plates 23, and the connecting plate 23 at the top of the single pillar 7 and the connecting plate 23 at the bottom of the reinforcement rod 15 are fixedly connected by bolts.

[0100] This structure strengthens the connection stability between the single pillar and the reinforcement rod, ensuring the stability and safety of the entire support system.

[0101] The connection is fixed by bolts, which makes disassembly and assembly quick and easy, and facilitates maintenance and replacement of parts.

[0102] The setting of the connecting plate makes the connection between the single support and the reinforcement rod tighter, effectively preventing loosening and falling off.

[0103] The bearing capacity and impact resistance of the overall structure are improved, ensuring the safety and stability of the support system.

[0104] Example 4

[0105] On the basis of Example 1, in step (4), the length of the grouting anchor rod and the grouting anchor cable 12 is determined comprehensively according to the height of the direct roof 2 and the basic roof 3 of the tunnel and the inclination of the coal seam 1. A grouting anchor cable with a length of 6.3 m and a grouting anchor rod with a length of 3.0 m are selected, and a mining anchor cable with a length of 4.1 m is selected for the solid coal side.

[0106] By strengthening the support, the overall stability of the tunnel is effectively improved and the safety hazards caused by roof collapse are reduced.

[0107] The selected lengths of grouting anchor rods and grouting anchor cables meet the actual needs of the tunnel structure and can effectively meet the support requirements.

[0108] A comprehensive support system, namely the anchor-net-beam-injection comprehensive support system, is adopted. It has a solid structure and can effectively support the tunnel roof and two sides, thereby improving the support effect of the asymmetric tunnel without coal pillars for top cutting and pressure relief of inclined coal seams.

[0109] After the working face was mined, natural support was adopted to pile the collapsed rocks on the upper side to the lower side, forming a stable support structure and reducing the cost and workload of secondary support.

[0110] The overall support work is carried out step by step, which ensures the stability of the tunnel and enables the support work of the entire tunnel to be completed step by step.

[0111] Example 5

[0112] On the basis of Example 1, in step (3), the top cutting pressure relief is a pulse-driven water flow fracturing method, by opening a plurality of top cutting drill holes 8 in the rock formation, injecting water into the top cutting drill holes 8 from the water injection port, starting the pulse transmitter to emit pulse waves, and adjusting the angle so that the pulse waves break the surrounding rock along the direction of the tunnel, gradually forming cracks.

[0113] By using the pulse-driven water flow fracturing method, cracks can be formed quickly, improving the mining efficiency of the rock formation.

[0114] By adjusting the angle so that the pulse wave breaks the surrounding rock along the direction of the tunnel, the direction and range of crack formation can be accurately controlled.

[0115] Compared with traditional blasting methods, the top cutting and pressure relief pulse driven water flow fracturing method does not require the use of a large amount of explosives, reducing energy consumption and impact on the environment.

[0116] Since no blasting chemicals are used, potential safety hazards during the blasting process are reduced, thus improving the safety of mining operations.

[0117] The top cutting and pressure relief pulse driven water flow fracturing method is a relatively environmentally friendly mining method, which is conducive to the sustainable mining of mineral resources.

[0118] Example 6

[0119] On the basis of Example 1, in step (2), the rock-blocking device is used in combination with high-water-filled materials and single pillars 7. Single pillars 7 are set in the coal mining working face 6 near the goaf roadway 4 to support the roof of the coal mining working face 6. Soft mold bags 10 are used to fill the high-water-filled materials along the side of the goaf 9. Anchor rods and grouting anchor cables are driven into the side and roof of the goaf roadway 4, and steel mesh is hung on the anchor rods to block rock.

[0120] This method can effectively prevent the collapse of the roof and the collapse of the rock retaining, ensuring the safe production of the coal mining face. At the same time, the combination of single pillars and flexible mold bags can better support the roof and fill high-water materials, improving the stability and bearing capacity of the support. In addition, the use of anchor rods and grouting anchor cables can enhance the stability of the geological body and reduce the risk of loosening and collapse of the surrounding rock. Overall, this design can effectively improve the support effect of the tunnel and ensure the safe production of the mine.

[0121] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A roof cutting and pressure relief support structure along the goaf, characterized in that: It comprises a goaf-side tunnel (4) opened along an inclined coal seam (1) and an anchor-net-beam-grouting comprehensive support system arranged on the goaf-side tunnel (4); The anchor-net-beam-grouting comprehensive support system comprises an anchor rod and cable support structure arranged on the top plate and both sides of the gob-side tunnel (4), a reinforced support provided by grouting anchor rods and grouting anchor cables (12), and a steel beam erected on the top plate; A rock-blocking device is arranged in the gob-side tunnel (4).

2. A gob-side tunnel roof cutting pressure relief support structure according to claim 1, characterized in that: The anchor rod and anchor cable support structure comprises a mining anchor rod (13) and a mining anchor cable (11); The mining anchor (13) is provided with a metal mesh; The metal mesh is covered on the roof of the gob-side tunnel (4) to form an anchor mesh; The mining anchor cables (11) are symmetrically arranged along the center line on the left and right sides of the empty tunnel (4).

3. A gob-side tunnel top cutting pressure relief support structure according to claim 2, characterized in that: The rock-blocking device comprises a single pillar (7), a double-layer metal mesh and a flexible mold bag (10), wherein the double-layer metal mesh is fixed to a side of the single pillar (7) close to the goaf (9), the flexible mold bag (10) is arranged inside the double-layer metal mesh, and a high-water filling material is injected into the flexible mold bag (10) to seal the goaf (9); The single support (7) is a hydraulic support.

4. A gob-side tunnel roof cutting pressure relief support structure according to claim 3, characterized in that: A top cutting drill hole (8) is provided on the top plate of the gob-side tunnel (4), and the top cutting drill hole (8) is drilled into the interior of the basic top (3) through the direct top (2); A pulse device is arranged below the top-cutting drill hole (8), the pulse device comprising a hole sealer, a push rod and a pulse generator, and a water injection port is arranged below the hole sealer.

5. The pressure relief support structure for cutting the roof of a goaf-side tunnel according to claim 2 is characterized in that: The roof of the gob-side tunnel (4) has an inclination angle the same as that of the coal seam (1), and the bottom rock layer (5) is horizontally excavated.

6. The pressure relief support structure for cutting the roof of a gob-side tunnel according to claim 3 is characterized in that: It also includes a reinforcement device, the reinforcement device including a reinforcement rod (15) arranged at the top of the single pillar (7), a clamp assembly arranged at the bottom of the single pillar (7) and on the reinforcement rod (15), a connecting rod (16) is arranged between the clamp assemblies at the bottom of adjacent single pillars (7), and a connecting rod (16) is arranged between the clamp assembly at the bottom of the single pillar (7) and the clamp assembly on the reinforcement rod (15) at the top of the adjacent single pillar (7); The clamp assembly comprises two semi-annular clamps (17), both ends of the clamps (17) are provided with ear plates, and the ear plates of the two clamps (17) are fixedly connected by bolts; An upper and lower transverse plates (18) are arranged on the outer wall of the clamp (17), a connecting block (19) is arranged between the upper and lower transverse plates (18), vertical threaded holes are opened on the upper and lower transverse plates (18) and one end of the connecting block (19), and the upper and lower transverse plates (18) and one end of the connecting block (19) are fixedly connected by bolts; The other end of the connecting block (19) is provided with two left and right vertical plates (20), and the vertical plates (20) are provided with transverse threaded holes. The connecting rod (16) is connected between the left and right vertical plates (20), and both ends of the connecting rod (16) are provided with threaded holes. The left and right vertical plates (20) are fixedly connected to the ends of the connecting rod (16) by bolts. An annular limiting groove (21) is provided on the opposite side walls of the left and right vertical plates (20), and the inner diameter of the limiting groove (21) is larger than the diameter of the threaded hole; Limiting rings (22) are arranged on both sides of the end of the connecting rod (16), and the limiting rings (22) are slidably matched with the limiting grooves (21); A connecting plate (23) is provided at the top of the single pillar (7), and connecting plates (23) are provided at the top and bottom of the reinforcement rod (15). Threaded holes are provided on the connecting plates (23), and the connecting plate (23) at the top of the single pillar (7) and the connecting plate (23) at the bottom of the reinforcement rod (15) are fixedly connected by bolts.

7. A support method for the goaf-side tunnel top cutting pressure relief support structure according to any one of claims 1 to 5, characterized in that: The steps include: Step (1) Basic support: A tunnel along the goaf (4) is excavated along the inclined coal seam (1), an anchor rod and anchor cable support structure is set on the roof and two sides of the tunnel along the goaf (4), and a metal mesh is set on the mining anchor rod (13) to cover the roof of the tunnel along the goaf (4), forming an anchor mesh; Step (2): A single support column (7) is arranged at the lower wall and the upper wall of the gob-side tunnel (4) in front of the coal mining working face (6) to support the roof of the gob-side tunnel (4), and a rock blocking device is set up; Step (3): Before the coal mining face is mined, a plurality of top cutting drill holes (8) are opened in the rock layer at equal intervals along the extension direction of the empty roadway (4) at the mining face, and the top cutting drill holes (8) are extended obliquely from the direct top (2) to the inside of the basic top (3) at its upper end, and pulse wave hydraulic top cutting and pressure relief are performed; Step (4): Strengthening support: strengthening support by grouting anchor rods and grouting anchor cables (12), and setting up steel beams on the top plate to form an anchor-net-beam-grouting comprehensive support system; Step (5): Temporary support is removed behind the coal mining working face (6), and a rock retaining device is left to pile up the collapsed rocks on the upper side of the goaf (9) to the lower side of the goaf (9) to form a natural support. Step (6): After the working face is mined, the gob-side tunnel (4) is gradually stabilized, the gob area is closed (9), and the remaining tunnel is completed; Step (7): Repeat steps (1)-(6) to complete the top cutting and pressure relief of the entire tunnel and the non-coal pillar asymmetric tunnel support work.

8. The supporting method of the gob-side tunnel top cutting pressure relief supporting structure according to claim 7 is characterized in that: In step (4), the lengths of the grouting anchor rods and grouting anchor cables (12) are determined comprehensively according to the heights of the direct roof (2) and the basic roof (3) of the tunnel and the inclination of the coal seam (1). A grouting anchor cable with a length of 6.3 m and a grouting anchor rod with a length of 3.0 m are selected, and a mining anchor cable with a length of 4.1 m is selected for the solid coal side.

9. The supporting method of the gob-side tunnel roof cutting and pressure relief supporting structure according to claim 7, characterized in that: In step (3), the top cutting pressure relief is a pulse driven water flow fracturing method, which is achieved by opening a plurality of top cutting boreholes (8) in the rock formation, injecting water into the top cutting boreholes (8) from the water injection port, starting the pulse transmitter to emit pulse waves, and adjusting the angle so that the pulse waves break the surrounding rock along the tunnel direction, gradually forming cracks.

10. The supporting method of the goaf-side tunnel roof cutting and pressure relief supporting structure according to claim 7, characterized in that: In step (2), the rock-blocking device is used in combination with a high-water-filled material and a single pillar (7). A single pillar (7) is set in the coal mining working face (6) near the goaf-side tunnel (4) to support the roof of the coal mining working face (6). A flexible mold bag (10) is used to fill the high-water-filled material on the side of the goaf (9). Anchor rods and grouting anchor cables are driven into the side and roof of the goaf-side tunnel (4), and a steel mesh is hung on the anchor rods to block rock.

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