Comprehensive waterproof method for coal mine goaf drainage and roadway rock wall crack grouting and water plugging

Abstract

The invention belongs to the field of coal mine water prevention and control, and particularly relates to a comprehensive waterproof method for coal mine goaf drainage and roadway rock wall crack grouting and water plugging. According to the method, the section transportation roadway is arranged from the transportation uphill to the open-off cut in a pseudo-upward inclined mode, the drainage grooves are formed in the section coal pillars, and the lower portions of the section coal pillars are subjected to waterproof treatment, so that water entering the goaf flows into the drainage grooves from high to low along the inclination direction, and the flowing direction of water flowing into the goaf from a roof water-containing rock stratum can be controlled; safe coal mining under the roof water-containing rock stratum is achieved, water is prevented from eroding the section coal pillar, and the reserved width of the section coal pillar is reduced. The hollow grouting and water plugging drilling tool designed by the invention is provided with the water stop plug, can drain water while plugging water during drilling, performs grouting and reinforcement on the periphery of the drilling rod after drilling to a designed depth, not only can fix the grouting and water plugging drilling tool, but also can plug water and discharge water from the hollow drilling rod to form a grouting and water plugging structure with controllable drainage; the problem of roadway water bursting caused by the fact that the original fissures are communicated with the water guiding fissure zone is solved.

Description

Technical Field

[0001] The invention belongs to the field of coal mine water prevention and control, and specifically relates to a comprehensive waterproofing method for drainage of coal mine goaf areas and grouting water blocking of tunnel rock wall cracks. Background Art

[0002] When there are water-bearing rock layers in the roof rock layer, and the water-conducting fissures formed during coal seam mining conduct the water-bearing rock layers, the water in the water-bearing rock layers will enter the coal mining face, affecting the production safety of the coal mining face. In this regard, the existing technologies mostly prevent or reduce the water in the water-bearing rock layers from flowing into the coal mining face by pre-draining the water-bearing rock layers before mining, leaving a large protective coal pillar (such as a section coal pillar) or reducing the thickness of coal seam mining to reduce the height of the water-conducting fracture zone. However, the pre-draining of water from the aquifer takes a long time, and this method cannot be used if the range of the water-bearing rock layers is very large. Leaving a large protective coal pillar (such as a section coal pillar) or reducing the thickness of coal seam mining will reduce the coal recovery rate, especially the strength of the protective coal pillar is reduced under long-term immersion or erosion in water, and the width of the protective coal pillar needs to be further increased, resulting in serious waste of resources. In addition, affected by the saddle-shaped development of the water-conducting fracture zone, when the next working face is mined at the section coal pillar, if there are primary fractures connecting the water-conducting fracture zone formed by the previous working face mining with the return air tunnel of the next working face, water damage will also occur in the return air tunnel of the next working face. Summary of the invention

[0003] In view of the above technical problems, the present invention proposes a comprehensive waterproofing method for drainage of coal mine goaf and grouting water blocking of tunnel rock wall cracks, comprising the following steps:

[0004] S1: Several coal mining faces are arranged in sequence along the inclination and numbered in sequence, and a section coal pillar is left between adjacent coal mining faces; each coal mining face is constructed with a section return air lane and a section transport lane along the pseudo-inclination of the strike, the section return air lane gradually rises from the section return air uphill to the cutting direction along the strike, and the section transport lane gradually rises from the section transport uphill to the cutting direction along the strike;

[0005] S2: In the section transport tunnel, close to the section coal pillar, a drainage ditch is constructed along the strike;

[0006] S3: The first mining face is mined, and the water entering the goaf is collected in the drainage trough;

[0007] S4: carry out mining work on the second working face, and the water entering the goaf is collected in the drainage trough;

[0008] S5: When the second working face is mined, grouting and water blocking treatment is performed on the original fractures that can conduct water-conducting fracture zones of the first mining working face.

[0009] Preferably, in step S1, the angle between the section transport lane, the section return air lane and the horizontal line along the direction is 5-10°.

[0010] Preferably, in step S2, a cover plate containing water holes is set on the drainage trough.

[0011] Preferably, in step S2, waterproofing treatment is performed at the lower part of the section coal pillar in the section transport tunnel.

[0012] Preferably, in steps S3 and S4, a water pump is provided in the drainage trough near the place where the water is transported up the mountain to discharge the water in the drainage trough.

[0013] Preferably, in step S5, a grouting and water-plugging drill tool is used to grout and water-plug the original fractures. The grouting and water-plugging drill tool includes a hollow drill rod and a hollow drill bit arranged at the top of the hollow drill rod. A water stop plug is tightly sleeved at the middle and lower part of the hollow drill rod, and a limit plate is fixed at the lower part of the water stop plug on the outer periphery of the hollow drill rod.

[0014] Preferably, in step S5, the water stopper is an annular frustum structure, the maximum outer diameter of the bottom of the water stopper is not less than the outer diameter of the limiting plate, and the outer diameter of the limiting plate and the maximum outer diameter of the bottom of the water stopper are not less than the diameter of the grouting water plugging borehole drilled by a hollow drill bit.

[0015] Preferably, in step S5, a drainage hole is provided on the hollow drill rod between the hollow drill bit and the water stopper.

[0016] Preferably, in step S5, the grouting and water plugging drilling tool is further provided with a tray and a locking nut, the tray is slidably connected to the hollow drill rod, and the locking nut is threadedly connected to the hollow drill rod.

[0017] Preferably, in step S5, for quasi-circular fissures with smaller diameters, a grouting water-plugging drill tool is used to construct a grouting water-plugging borehole along the quasi-circular fissure, and the quasi-circular fissure is located within the aperture of the grouting water-plugging borehole. When the construction reaches the set depth, the grouting water-plugging drill tool is fixed, and water-plugging slurry is injected into the grouting water-plugging borehole below the limit plate; water is discharged from the hollow drill rod to form a grouting water-plugging structure with controllable drainage.

[0018] Preferably, in step S5, for flat cracks with a larger length, a grouting and water plugging drill is used to construct a grouting and water plugging borehole at the position of the maximum crack width of the flat crack along the development depth direction of the flat crack. When the construction reaches the set depth, the grouting and water plugging drill is fixed; the sealing and waterproof material is inserted into the portion of the flat crack that exceeds the aperture of the grouting and water plugging borehole, the water plugging slurry is injected into the grouting and water plugging borehole below the limit plate, and the water plugging slurry is injected into the flat cracks outside the sealing and waterproof material; water is discharged from the hollow drill rod to form a grouting and water plugging structure with controllable drainage.

[0019] Preferably, the method further includes step S6: arranging and mining the third working face according to the arrangement and mining method of the second working face, and so on until all coal mining working faces in the mining area are mined.

[0020] Beneficial technical effects: 1. The present invention arranges the section transport tunnel in a pseudo-upward inclination from the transport uphill to the cutting direction, and sets a drainage ditch at the section coal pillar, and waterproofs the lower part of the section coal pillar, so that the water entering the goaf flows into the drainage ditch from high to low along the inclination, and then flows along the direction of the water's own weight to be transported uphill and then discharged. The flow direction of water flowing into the goaf from the water-bearing rock layer on the roof can be controlled, safe coal mining under the water-bearing rock layer on the roof can be achieved, and water can be prevented from eroding the section coal pillar, maintaining the strength of the section coal pillar, and reducing the width of the section coal pillar.

[0021] 2. The hollow grouting and water-blocking drill tool designed in the present invention is equipped with a water-stop plug, which can drill holes, drain water and block water at the same time. After drilling to the designed depth, the outer periphery of the drill pipe can also be grouting reinforced. On the one hand, it plays a role in fixing the grouting and water-blocking drill tool, and on the other hand, it plays a role in blocking water. Water is discharged from the hollow drill pipe to form a grouting and water-blocking structure with controllable drainage, thereby solving the problem of water gushing in the tunnel caused by the original fissure conductive water-conducting fissure zone. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the plane layout of the comprehensive waterproofing method during the first mining face mining of the present invention;

[0023] Figure 2 It is a schematic diagram of the plan layout of the comprehensive waterproofing method during mining at the second working face of the present invention;

[0024] Figure 3 It is a cross-sectional schematic diagram of the comprehensive waterproofing method during mining of the second working face of the present invention;

[0025] Figure 4 This is a schematic diagram of water grouting for blocking the cracks in the rock wall of the tunnel during the second working face mining of the present invention;

[0026] Figure 5 This is a schematic diagram of the structure of the tunnel rock wall crack grouting and water blocking drilling tool of the present invention;

[0027] Figure 6 It is a schematic diagram of the tunnel rock wall grouting water blocking structure 10 of the present invention;

[0028] Figure 7 This is a schematic diagram of the construction position of the circular crack water blocking drilling hole in the tunnel rock wall of the present invention;

[0029] Figure 8 This is a schematic diagram of the construction position of the water-blocking drilling hole for the flat cracks on the rock wall of the tunnel according to the present invention;

[0030] In the figure, return air uphill 1, transport uphill 2, section return air lane 3, section transport lane 4, drainage ditch 5, goaf 6, section coal pillar 7, first mining working face 8, second working face 9, grouting and water blocking structure 10, waterproof layer 11, water-conducting fracture zone 12, original fracture 13, hollow drill bit 14, hollow drill rod 15, drainage hole 16, water stop plug 17, limit plate 18, tray 19, circular fracture 20, flat fracture 21, sealing and waterproof material 22, grouting and water blocking drill hole 23, water blocking slurry 24, eye cutting 25, locking nut 26. DETAILED DESCRIPTION

[0031] The present invention will be further described below in conjunction with the accompanying drawings.

[0032] like Figure 1-8 As shown, the present invention proposes a comprehensive waterproofing method for drainage of coal mine goaf and grouting water blocking of tunnel rock wall cracks, comprising the following steps:

[0033] S1: Figure 1-2 As shown, several coal mining faces are arranged in sequence along the inclination, and a section coal pillar 7 is left between adjacent coal mining faces. Figure 1-2 Two coal mining working faces are shown in the figure, including a first mining working face 8 with a relatively shallow burial depth and a second mining working face 9 with a relatively deep burial depth. A third working face, a fourth working face and other multiple coal mining working faces may be arranged along the inclination after the second working face 9;

[0034] Each coal mining face is constructed with a section return air lane 3 and a section transport lane 4 roughly along the strike. According to the characteristic that the airflow tends to flow upward, the section return air lane 3 is at a high position of the inclination, and the section transport lane 4 is at a low position of the inclination (this is a design method known in the art and will not be described in detail here); the section return air lane 3 and the section transport lane 4 are roughly arranged in a pseudo-oblique manner along the strike, and the angle between them and the horizontal line along the strike is 5-10°. The section return air lane 3 is connected to the return air uphill 1, and the section return air lane 3 gradually rises along the strike from the return air uphill 1 to the direction of the cutting eye 25 (pseudo-oblique arrangement). The section transport lane 4 is connected to the transport uphill 2, and the section transport lane 4 gradually rises along the strike from the transport uphill 2 to the direction of the cutting eye 25 (pseudo-oblique arrangement);

[0035] S2: Figure 1-4 As shown, in the section transport lane 4, close to the section coal pillar 7, a drainage ditch 5 is constructed along the direction, and a cover plate with water holes is set on the drainage ditch 5; waterproof treatment is performed on the lower half of the section coal pillar 7 in the section transport lane 4 to form a waterproof treatment layer 11;

[0036] S3: The first mining face 8 is mined, and the water-conducting fracture zone 12 formed by the mining may conduct the water-bearing rock layer in the roof. The water in the water-bearing rock layer enters the goaf 6 formed by the mining of the first mining face 8 from the water-conducting fracture zone 12; the height of the rock layer at the bottom of the goaf 6 gradually decreases from the section return air lane 3 to the section transport lane 4, so the water entering the goaf 6 will be collected in the drainage trough 5, and because the lower half of the section coal pillar 7 is waterproofed, even if there is a sudden increase in water volume, the water cannot enter the section coal pillar 7, and the water collected in the drainage trough 5 can be further discharged by its own weight (the drainage trough is arranged pseudo-inclined along the direction), and a water pump is arranged near the transportation uphill 2 of the drainage trough 5 to further improve the drainage efficiency, that is, by setting the drainage trough 5 and waterproofing the section coal pillar 7, the water in the goaf 6 can be discharged in time, and the water scouring of the section coal pillar 7 can be avoided to affect its strength, thereby reducing the remaining width of the section coal pillar 7 and improving the overall coal recovery rate;

[0037] S4: After the first mining face 8 is mined, the second mining face 9 is mined. The water-conducting fracture zone 12 formed by the mining may conduct the water-bearing rock layer in the roof. The water in the water-bearing rock layer enters the goaf 6 formed by the mining of the second mining face 9 from the water-conducting fracture zone 12; the rock layer at the bottom of the goaf 6 gradually decreases in height from the section return air lane 3 to the section transport lane 4, so the water entering the goaf 6 will be collected in the drainage trough 5, and because the lower half of the section coal pillar 7 is waterproofed, even if there is water In the case of a sudden large amount of water, water cannot enter the section coal pillar 7, and the water collected in the drainage trough 5 can be further discharged by its own weight (the drainage trough is arranged pseudo-inclined along the direction). The water pump is arranged near the transportation uphill 2 in the drainage trough 5 to further improve the drainage efficiency. That is, by setting the drainage trough 5 and waterproofing the section coal pillar 7, the water in the goaf 6 can be discharged in time, and the water scouring of the section coal pillar 7 can be avoided to affect its strength, thereby reducing the width of the section coal pillar 7 and improving the overall recovery rate of coal;

[0038] S5: When the second working face 9 is being mined, there may be some original fractures 13 (or fractures formed by the construction of the section return air lane 3) connected to the water-conducting fracture zone 12 formed by the mining of the first mining working face 8, so that the water in the water-bearing rock formation enters the section return air lane 3 of the second working face 9 through the water-conducting fracture zone 12 and the original fractures 13; in this regard, grouting and water blocking are performed on the original fractures 13 to prevent the water in the water-conducting fracture zone 12 formed by the mining of the first mining working face 8 from entering the section return air lane 3 of the second mining working face 9 from the original fractures 13;

[0039] S6: Arrange and mine the third working face according to the arrangement and mining method of the second working face 9, and so on until all coal mining working faces in the mining area are mined.

[0040] Among them, in step S5, the following technical solutions can be adopted to grout and plug the original fissure 13:

[0041] S51: Design grouting and water plugging drilling tools, such as Figure 5-6 As shown, the grouting and water plugging drilling tool includes a hollow drill rod 15 and a hollow drill bit 14 arranged at the top of the hollow drill rod 15. The middle and lower part of the hollow drill rod 15 is tightly sleeved with a water stop plug 17. The lower part of the water stop plug 17 is a limit plate 18. The limit plate 18 is a circular ring structure. The limit plate 18 is fixedly connected to the hollow drill rod 15, such as by threaded connection or welding. The water stop plug 17 is an annular truncated cone structure, and the maximum outer diameter of the bottom of the water stop plug 17 is not less than 1. The outer diameter of the limit plate 18 is smaller than that of the limit plate 18, and the outer diameter of the limit plate 18 and the maximum outer diameter of the bottom of the water stopper 17 are not smaller than the diameter of the grouting and water plugging borehole 23 drilled by the hollow drill bit 14; a drainage hole 16 is provided on the hollow drill rod 15 between the hollow drill bit 14 and the water stopper 17; the grouting and water plugging drill tool is also equipped with a tray 19 and a locking nut 26, the tray 19 is slidably connected to the hollow drill rod 15, and the locking nut 26 is threadedly connected to the hollow drill rod 15;

[0042] S52: When water leakage is found in the original crack 13 in the section return air channel 3, and it is a circular crack 20, if Figure 4 , Figure 6-7 As shown, a grouting water-blocking drill tool is used to construct a grouting water-blocking borehole 23 along the quasi-circular fissure 20. The grouting water-blocking borehole 23 completely covers the quasi-circular fissure 20, that is, the quasi-circular fissure 20 is located within the aperture of the grouting water-blocking borehole 23. During the construction of the grouting water-blocking drill tool, water and rock powder generated by drilling flow out from the hollow drill bit 14 and the hollow drill rod 15. The hollow drill rod 15 is connected to a drainage pipe to discharge the water flowing out of the hollow drill rod. During the drilling process, the water stopper 17 plays a role in water blocking, and the limit plate 18 can prevent the water stopper 17 from moving, and water will not flow out of the grouting water plugging borehole 23. In addition, the drainage hole 16 will further increase the effect of drainage and rock powder removal. When the construction reaches the set depth, tighten the locking nut 26 to fix the grouting water plugging drill, and inject the water plugging slurry 24 into the grouting water plugging borehole 23 below the limit plate 18. On the one hand, it plays a role in fixing the grouting water plugging drill, and on the other hand, it plays a role in water plugging. Water is discharged from the hollow drill rod 15 to form a grouting water plugging structure 10 with controllable drainage.

[0043] S53: When water leakage is found in the original fissure 13 in the section return airway 3, and the fissure is a flat fissure 21, and the flat fissure 21 is larger than the diameter of the grouting water plugging borehole 23 that can be drilled by the grouting water plugging drill; Figure 4 , Figure 6 , Figure 8As shown, a grouting and water-blocking drill tool is used to construct a grouting and water-blocking borehole 23 at the maximum crack width position of the flat crack 21 along the development depth direction of the flat crack 21. During the construction of the grouting and water-blocking drill tool, water and rock powder generated by drilling flow out from the hollow drill bit 14 and the hollow drill rod 15. The hollow drill rod 15 is connected to a drainage pipe to discharge the water flowing out of the hollow drill rod. During the drilling process, the water stop plug 17 plays a water blocking role, and the limit plate 18 can prevent the water stop plug 17 from moving, so that water will not flow out of the grouting and water-blocking borehole 23. In addition, the drainage hole 16 will further increase the effect of drainage and rock powder removal; because water will flow out of the hollow drill rod 15 with a larger aperture, and at the same time will flow out through the hollow drill rod 15 through the drainage hole 16, the water flow of the flat crack 21 that exceeds the aperture of the grouting and water-blocking borehole 23 will be greatly reduced. When the construction reaches the set depth, tighten the locking nut 26 to fix the grouting and water-blocking drill tool;

[0044] The sealing waterproof material 22 is inserted into the portion of the flat crack 21 that exceeds the aperture of the grouting water-blocking drill hole 23 from the section return air channel 4 to block the portion of the flat crack 21 that exceeds the aperture of the grouting water-blocking drill hole 23, and the water-blocking slurry 24 is injected into the grouting water-blocking drill hole 23 below the limit plate 18. The water-blocking slurry 24 is injected into the flat crack 21 outside the sealing waterproof material 22. On the one hand, it plays a role in fixing the grouting water-blocking drill tool and the sealing waterproof material 22, and on the other hand, it plays a role in blocking water. Water is discharged from the hollow drill rod 15 to form a grouting water-blocking structure 10 with controllable drainage.

[0045] The present invention is not limited to the above-mentioned optimal implementation mode. Anyone can derive other various forms of methods under the inspiration of the present invention. Any technical solution that is the same or similar to that of the present application falls within the protection scope of the present invention.

Claims

1. A comprehensive waterproofing method for drainage of coal mine goaf and grouting water blocking of tunnel rock wall cracks, characterized in that: The following steps are involved: S1: Several coal mining faces are arranged in sequence along the inclination and numbered in sequence, and a section coal pillar is left between adjacent coal mining faces; each coal mining face is constructed with a section return air lane and a section transport lane along the pseudo-inclination of the strike, the section return air lane gradually rises from the section return air uphill to the cutting direction along the strike, and the section transport lane gradually rises from the section transport uphill to the cutting direction along the strike; S2: In the section transport tunnel, close to the section coal pillar, a drainage ditch is constructed along the strike; S3: The first mining face is mined, and the water entering the goaf is collected in the drainage trough; S4: carry out mining work on the second working face, and the water entering the goaf is collected in the drainage trough; S5: When the second working face is mined, grouting and water blocking treatment is performed on the original fractures that can conduct water-conducting fracture zones of the first mining working face.

2. The comprehensive waterproofing method according to claim 1, characterized in that: In step S1, the angle between the section transport lane, the section return air lane and the horizontal line along the direction is 5-10°.

3. The comprehensive waterproofing method according to claim 1, characterized in that: In step S2, a cover plate containing water holes is set on the drainage trough; and / or waterproofing treatment is performed on the lower part of the section coal pillar in the section transport lane.

4. The comprehensive waterproofing method according to any one of claims 1 to 3, characterized in that: In step S5, a grouting and water-plugging drill tool is used to grout and plug water in the original fractures. The grouting and water-plugging drill tool includes a hollow drill rod and a hollow drill bit arranged at the top of the hollow drill rod. A water stop plug is tightly sleeved at the middle and lower part of the hollow drill rod, and a limit plate is fixed at the lower part of the water stop plug on the outer periphery of the hollow drill rod.

5. The comprehensive waterproofing method according to claim 4, characterized in that: In step S5, the water stopper is an annular truncated cone structure, the maximum outer diameter of the bottom of the water stopper is not less than the outer diameter of the limiting plate, and the outer diameter of the limiting plate and the maximum outer diameter of the bottom of the water stopper are not less than the diameter of the grouting and water plugging borehole drilled by a hollow drill bit.

6. The comprehensive waterproofing method according to claim 5, characterized in that: In step S5, a drainage hole is provided on the hollow drill rod between the hollow drill bit and the water stopper.

7. The comprehensive waterproofing method according to claim 6, characterized in that: In step S5, the grouting and water plugging drilling tool is further configured with a tray and a locking nut, the tray is slidably connected to the hollow drill rod, and the locking nut is threadedly connected to the hollow drill rod.

8. The comprehensive waterproofing method according to claim 7, characterized in that: In step S5, for quasi-circular cracks with smaller diameters, a grouting and water-plugging drill is used to construct a grouting and water-plugging borehole along the quasi-circular cracks. The quasi-circular cracks are located within the diameter of the grouting and water-plugging borehole. When the construction reaches the set depth, the grouting and water-plugging drill is fixed, and water-plugging slurry is injected into the grouting and water-plugging borehole below the limit plate; water is discharged from the hollow drill rod to form a grouting and water-plugging structure with controllable drainage.

9. The comprehensive waterproofing method according to claim 7, characterized in that: In step S5, for flat cracks with a larger length, a grouting and water-plugging drill is used to construct a grouting and water-plugging borehole at the position of the maximum crack width of the flat crack along the development depth direction of the flat crack. When the construction reaches the set depth, the grouting and water-plugging drill is fixed; the sealing and waterproofing material is inserted into the portion of the flat crack that exceeds the aperture of the grouting and water-plugging borehole, the water-plugging slurry is injected into the grouting and water-plugging borehole below the limit plate, and the water-plugging slurry is injected into the flat cracks outside the sealing and waterproofing material; water is discharged from the hollow drill rod to form a grouting and water-plugging structure with controllable drainage.

10. The comprehensive waterproofing method according to any one of claims 1-3 and 5-9, characterized in that: The method further includes step S6: arranging and mining the third working face according to the arrangement and mining method of the second working face, and so on until all coal mining working faces in the mining area are mined.

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