Stress regulation and control roadway protection method for mining stopping line roadway driving pre-grouting reinforcement

Abstract

The invention belongs to the technical field of surrounding rock stability control, and particularly relates to a stress regulation and control roadway protection method for mining stopping line roadway driving pre-grouting reinforcement, which comprises the following steps of: driving a newly-dug roadway between a mining stopping line of a working face and a protected main roadway; multiple groups of grouting holes are constructed in the two sides of the newly-dug roadway; superfine cement paste is injected into the surrounding rocks on the two sides through the grouting holes, and a corresponding surrounding rock grouting reinforcement range is formed; and after the working face is pushed to the mining stopping line, a support removing channel is formed, and surrounding rocks on the top and the sides of the support removing channel are both located within the grouting reinforcement range. According to the method, the stopping line support removing channel and the main roadway protection coal pillar are reinforced at the same time, the bearing capacity of the coal pillar is enhanced, an effective supporting effect on an overlying rock stratum can be achieved, and mining-induced stress transfer caused by crushing of the coal pillar is avoided; on the other hand, the newly-dug roadway absorbs a considerable part of energy through self deformation, and the pressure relief effect is achieved. Through combination of pressure control and pressure relief, stress regulation and control are achieved, and then the main roadway is protected.

Description

Technical Field

[0001] The invention belongs to the technical field of surrounding rock stability control, and in particular relates to a stress regulation and tunnel protection method for pre-grouting reinforcement of tunneling on a stopped mining line. Background Art

[0002] Long-arm mining is the main mining method for coal resources in my country. Under this mining mode, the main tunnel in the panel area needs to serve multiple working faces. The mining stress, especially the advance support stress, has a great impact on the stability of the main tunnel. Under the action of the advance support stress, the surrounding rock of the tunnel undergoes multiple stress redistributions, the stress environment and bearing capacity continue to deteriorate, and the risk of instability is also increasing.

[0003] Although the adverse effects on the main tunnel can be reduced by leaving a wider protective coal pillar, it is very easy to cause a waste of coal resources. At the same time, the coal pillar is compressed and damaged under the action of the advance support stress, and the bearing capacity is greatly reduced, which in turn causes the peak point of the advance support stress to shift toward the main tunnel, seriously threatening the safety and stability of the surrounding rock of the main tunnel. With the increasing depletion of coal resources, how to effectively solve the problem of mining stress transfer without increasing the size of the coal pillar and ensure the basic stability of the tunnel surrounding rock is one of the technical problems that need to be solved urgently. Summary of the invention

[0004] In view of the problems existing in the above-mentioned prior art, the present invention discloses a stress control and tunnel protection method for pre-grouting reinforcement of tunneling on a stop-mining line. Through the tunneling pre-grouting reinforcement process, the stress control of the surrounding rock of the large tunnel is realized, and the following technical solutions are specifically disclosed:

[0005] A method for protecting a tunnel by stress regulation and pre-grouting reinforcement of a tunnel on a stop-mining line, comprising the following steps:

[0006] S01. Excavate a new tunnel between the stop mining line of the working face and the protected main tunnel;

[0007] S02. Construct three groups of grouting holes on both sides of the newly excavated tunnel. From top to bottom, the mining side is equipped with Group I holes, Group II holes, and Group III holes. From top to bottom, the main tunnel side is equipped with Group I holes, Group II holes, and Group III holes.

[0008] S03. Install the borehole pipe and spray concrete on the entire section of the newly excavated tunnel to seal the surrounding rock and prevent the grout from being exposed during grouting;

[0009] S04. Inject ultrafine cement slurry into the surrounding rocks on both sides through the orifice pipe to form a corresponding surrounding rock grouting reinforcement range;

[0010] S05. After the working face advances to the stop-mining line, a support withdrawal channel is formed, and the top and side surrounding rocks of the support withdrawal channel are within the grouting reinforcement range.

[0011] Furthermore, the three groups of grouting holes in S02 are distributed radially along the two sides of the newly excavated tunnel.

[0012] Furthermore, the final positions of the Group I holes and the Group II holes on the mining side in S02 are located 1500mm to 3000mm above the coal seam roof, ensuring effective reinforcement of the coal seam roof and the coal-rock contact surface. At the same time, the final positions of the Group II holes and the Group III holes on the mining side exceed the stop-mining line and are located at the tail of the coal mining hydraulic support, so as to achieve pre-reinforcement of the surrounding rock of the support withdrawal channel after stopping mining.

[0013] Furthermore, the final hole position of Group I holes on the side of the S02 middle and large tunnel is located 1500mm to 3000mm above the coal seam roof, ensuring effective reinforcement of the coal seam roof and the coal-rock contact surface.

[0014] Furthermore, the water-cement ratio of the ultrafine cement slurry used in grouting in S04 is controlled at 0.8 ～ 1.2, add 1% dispersant of cement dosage, and prepare slurry by high-speed mixer to ensure that the slurry can fully penetrate into the cracks of surrounding rock.

[0015] Furthermore, the grouting pressure at the bottom of the grouting holes on the side of the main tunnel in S04 is controlled at 3MPa~5MPa to prevent slurry from invading the main tunnel; the grouting pressure at the bottom of the group I holes on the mining side is controlled at 5MPa~8MPa, and the grouting pressure at the bottom of the group II holes and the group III holes on the mining side is controlled at 8MPa~10MPa.

[0016] Compared with the prior art, the present invention has the following beneficial effects: the present invention adopts the pre-grouting reinforcement process for tunneling, and a new tunnel is dug in the coal pillar protecting the mining line, and grouting is performed on the coal seams and the roof on both sides. Construction in the mining influence area can effectively reduce the safety risk. After the pre-grouting of tunneling is completed, on the one hand, the withdrawal channel of the mining line and the coal pillar protecting the main tunnel are reinforced at the same time, and the bearing capacity of the coal pillar is enhanced, which can effectively support the overlying rock strata, avoid the transfer of mining stress caused by the crushing of the coal pillar, and reduce the stress disturbance to the main tunnel; on the other hand, since the newly dug tunnel is closer to the stress peak point than the protected main tunnel, it absorbs a considerable part of the energy through its own deformation, reduces the stress concentration of the surrounding rock of the main tunnel, and plays a role in pressure relief. By combining pressure control and pressure relief, the stress state of the surrounding rock of the protected tunnel is improved. Therefore, the tunneling pre-grouting process of the present invention realizes the stress regulation of the surrounding rock of the main tunnel, thereby improving the stress environment of the surrounding rock of the main tunnel and playing a role in protecting the main tunnel. The present invention is simple to operate, economical and reasonable, and has certain promotion and application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a cross-sectional view of the drilling arrangement for pre-grouting of tunnel excavation;

[0018] Figure 2 This is a schematic diagram of the working face after mining is stopped;

[0019] Figure 3 is a schematic diagram of the stress transfer process of the advance support when the present invention is not implemented;

[0020] Figure 4 It is a schematic diagram of the stress distribution of the advance support after the implementation of the present invention.

[0021] Among them, 1-protected main tunnel; 2-stop mining line; 3-new tunnel; 4-Group I holes on the mining side; 5-Group II holes on the mining side; 6-Group III holes on the mining side; 7-Group I holes on the tunnel side; 8-Group II holes on the tunnel side; 9-Group III holes on the tunnel side; 10-concrete; 11-grouting reinforcement scope; 12-removal channel; 13-hydraulic support; 14-initial advance support stress; 15-support stress after transfer; 16-support stress after pre-grouting. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] Example 1

[0024] Reference Figure 1-2 This embodiment discloses a method for stress regulation and tunnel protection by pre-grouting reinforcement of tunneling on a stop-mining line, comprising the following steps:

[0025] S01. Excavate a new tunnel 3 between the working face stop mining line 2 and the protected main tunnel 1;

[0026] S02. Construct three groups of grouting holes on both sides of the newly excavated tunnel 3. The three groups of grouting holes are radially distributed along the two sides of the newly excavated tunnel 3. The mining side has Group I holes 4, Group II holes 5, and Group III holes 6 from top to bottom. The main tunnel side has Group I holes 7, Group II holes 8, and Group III holes 9 from top to bottom.

[0027] S03. Install the orifice pipe and spray concrete 10 on the entire section of the newly excavated tunnel 3 to seal the surrounding rock and prevent the grout from being exposed during grouting;

[0028] S04. Inject ultrafine cement slurry into the surrounding rocks on both sides through the orifice pipe to form the corresponding surrounding rock grouting reinforcement range 11. The water-cement ratio of the ultrafine cement slurry is controlled at 0.8 ～1.2, add 1% dispersant of cement, and prepare slurry by high-speed mixer at the same time to ensure that the slurry can fully penetrate into the cracks of the surrounding rock. The grouting pressure should be determined according to the reinforcement depth, surrounding rock characteristics, ground stress, etc. The grouting pressure on the main tunnel side should not be too high. In this embodiment, the grouting pressure at the bottom of the grouting hole is controlled at 3MPa~5MPa to prevent the slurry from invading the main tunnel; the grouting pressure on the mining side should be appropriately increased to ensure that the slurry is fully split and penetrated. In this embodiment, the grouting pressure of the mining side group I hole 4 is controlled at 5MPa~8MPa, and the grouting pressure of the mining side group II hole 5 and the mining side group III hole 6 is controlled at 8MPa~10MPa;

[0029] S05. After the working face advances to the stop mining line 2, a support withdrawal channel 12 is formed, and the top and side surrounding rocks of the support withdrawal channel 12 are both within the grouting reinforcement range 11.

[0030] As a preferred embodiment of the present invention, the final hole positions of the mining side group I holes 4 and the mining side group II holes 5 in S02 are located 1500mm to 3000mm above the coal seam roof, ensuring effective reinforcement of the coal seam roof and the coal-rock contact surface. At the same time, the final hole positions of the mining side group II holes 5 and the mining side group III holes 6 exceed the stop-mining line and are located at the tail end of the coal mining hydraulic support 13, so as to realize the pre-reinforcement of the surrounding rock of the support withdrawal channel 12 after stopping mining.

[0031] The final hole position of group 7 holes on the side of the S02 medium and large tunnel is located 1500mm to 3000mm above the coal seam roof, ensuring effective reinforcement of the coal seam roof and the coal-rock contact surface.

[0032] like Figure 3 As shown, before the implementation of the present invention, after the working face stops mining, an initial advance support stress 14 is formed in front of the coal mining face, and as the coal wall is compressed and damaged, the advance support pressure 14 is transferred to the deep to form a transferred support stress 15. The peak point of the transferred support stress 15 is closer to the main tunnel 1, which can easily induce the surrounding rock crushing and large deformation of the main tunnel. By implementing the tunnel protection construction method of the present invention, the pre-grouting reinforcement of the withdrawal channel 12 of the stop mining line and the protective coal pillar is firstly realized, and the mining stress transfer process caused by the compression and damage of the coal pillar is blocked, and the higher concentrated stress, that is, the pre-grouting support stress 16 is controlled between the stop mining line 2 and the new tunnel 3. At the same time, the deformation of the new tunnel 3 itself has a pressure relief effect, and the purpose of stress control and tunnel protection combining pressure control and pressure relief is achieved.

[0033] The above description is only a preferred embodiment of the present invention and does not limit the technical scope of the present invention. Therefore, any slight modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for protecting lanes by stress regulation and pre-grouting reinforcement of lanes in a stopped mining line, characterized in that: The following steps are involved: S01. Excavating a new tunnel (3) between the working face stop mining line (2) and the protected main tunnel (1); S02. Construct three groups of grouting holes on both sides of the newly excavated tunnel (3). From top to bottom, the mining side is provided with the mining side group I holes (4), mining side group II holes (5), and mining side group III holes (6). From top to bottom, the main tunnel side is provided with the main tunnel side group I holes (7), main tunnel side group II holes (8), and main tunnel side group III holes (9); S03. Install the orifice pipe and spray concrete (10) on the new tunnel (3) to seal the surrounding rock and prevent the grouting from being exposed; S04. Injecting ultrafine cement slurry into the surrounding rocks on both sides through the orifice pipe to form a corresponding surrounding rock grouting reinforcement range (11); S05. After the working face advances to the stop mining line (2), a support withdrawal channel (12) is formed, and the top and side surrounding rocks of the support withdrawal channel (12) are both within the grouting reinforcement range (11).

2. The stress control and tunnel protection method of pre-grouting reinforcement of the tunneling line of the stop mining line according to claim 1 is characterized in that: In S02, three groups of grouting holes are distributed radially along the two sides of the newly excavated tunnel (3).

3. The stress control and tunnel protection method of pre-grouting reinforcement of the tunneling line of the stop mining according to claim 1 is characterized in that: The final hole positions of the mining side group I holes (4) and the mining side group II holes (5) in S02 are located 1500mm to 3000mm above the coal seam roof, ensuring effective reinforcement of the coal seam roof and the coal-rock contact surface. At the same time, the final hole positions of the mining side group II holes (5) and the mining side group III holes (6) exceed the stop-mining line and are located at the tail of the coal mining hydraulic support (13) to achieve pre-reinforcement of the surrounding rock of the support withdrawal channel (12) after stopping mining.

4. The stress control and tunnel protection method for pre-grouting reinforcement of a tunnel driving line according to claim 1 is characterized in that: The final hole position of group I holes (7) on the side of the S02 middle and large tunnel is located 1500mm to 3000mm above the coal seam roof to ensure effective reinforcement of the coal seam roof and the coal-rock contact surface.

5. The stress control and tunnel protection method of pre-grouting reinforcement of tunneling on a stop-mining line according to claim 1 is characterized in that: The water-cement ratio of superfine cement slurry used in S04 grouting is controlled at 0.8 ～ 1.2, add 1% dispersant of cement dosage, and prepare slurry by high-speed mixer to ensure that the slurry can fully penetrate into the cracks of surrounding rock.

6. The stress control and tunnel protection method of pre-grouting reinforcement of tunneling on a stop-mining line according to claim 1 is characterized in that: The grouting pressure at the bottom of the grouting holes on the side of the main tunnel in S04 is controlled at 3MPa~5MPa to prevent the slurry from invading the main tunnel; the grouting pressure at the bottom of the hole group I (4) on the mining side is controlled at 5MPa~8MPa, and the grouting pressure at the bottom of the hole group II (5) and the hole group III (6) on the mining side is controlled at 8MPa~10MPa.

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