Downward crossing drilling reverse blasting outburst elimination method for tunnel outburst coal seam

Abstract

The invention belongs to the field of tunnel gas control, and discloses a downward crossing hole reverse blasting outburst elimination method for a tunnel outburst coal seam, which comprises the following steps of: forming two rows of downward extraction holes which are arranged in parallel on a coal seam step on a tunnel face; a row of blasting drill holes which are arranged in the same direction are formed in the middle position of the two rows of extraction drill holes, and the blasting drill holes and the extraction drill holes are coaxially arranged; hydraulic punching is conducted on the extraction drill holes and the blasting drill holes; the extraction drill hole is connected with an extraction pipeline for gas extraction; blasting explosive columns are placed in all the blasting drill holes; water is injected into the blasting drill holes until the liquid level is higher than the blasting grain; under the blasting effect, water can enter coal body pore cracks, the water is prevented from blocking an extraction and extraction channel, meanwhile, the water content of the coal body is increased, the dust amount can be obviously reduced in the later tunnel excavation process, the working environment of a tunnel face is improved, and water left by hydraulic measures can be effectively utilized.

Description

Technical Field

[0001] The invention belongs to the field of tunnel gas control, and in particular relates to a method for eliminating coal outbursts in tunnels by downward through-layer drilling and reverse blasting. Background Art

[0002] With the rapid development of transportation infrastructure construction in western my country, more and more tunnels are crossing coal-bearing strata, and gas tunnels have become a difficult project that cannot be avoided in transportation construction. During the process of tunnel coal excavation, coal and rock bodies in high ground stress and high gas environment are very likely to induce coal and gas outburst accidents, causing casualties and property losses. In order to prevent accidents, it is necessary to eliminate the outburst coal seams in advance.

[0003] When encountering a protruding coal seam in a tunnel, the coal seam is generally at a large angle to the tunnel excavation direction. If the tunnel face is located on the roof of the protruding coal seam, all types of anti-outburst drilling holes are downward drilling holes, and conventional hydraulic anti-outburst measures are difficult to achieve good results. The main reason is that it is difficult to discharge slag from downward drilling holes, and the water accumulated in the boreholes is difficult to discharge, which will block the gas extraction channel; therefore, there is a problem in the existing technology that residual water after hydraulic anti-outburst is easy to block the gas extraction channel. Summary of the invention

[0004] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a method for downward drilling through the layer and reverse blasting to eliminate the coal seam protrusion in the tunnel, which solves the problem in the prior art that residual water after hydraulic elimination of the protrusion easily blocks the gas extraction channel.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A method for eliminating coal outbursts by downward drilling and reverse blasting in a tunnel, comprising the following steps:

[0007] Two rows of downward extraction holes are placed side by side on the coal seam steps facing the palm face;

[0008] A row of blasting holes with the same arrangement direction is opened in the middle of the two rows of extraction holes, and the blasting holes are coaxially placed with the extraction holes;

[0009] Hydraulic flushing of each extraction borehole and blasting borehole;

[0010] Connect the extraction borehole to the extraction pipeline for gas extraction;

[0011] Blasting charges are placed in each blasting borehole;

[0012] Water is injected into the blasting borehole until the liquid level is higher than the blasting charge column;

[0013] The blasting borehole is sealed, the sealing position is above the liquid surface, and the detonation line is led through the sealing position to the outside of the blasting borehole;

[0014] The blasting columns in each blasting borehole are detonated simultaneously, and the detonated blasting boreholes are connected to the extraction pipeline for gas extraction;

[0015] The diameter of the extraction borehole is 153 mm, and the bottom of the extraction borehole is located at 2 / 3 of the thickness of the coal seam;

[0016] The two rows of extraction boreholes are placed symmetrically, with a spacing of 5m between them;

[0017] The distance between two adjacent extraction boreholes in each row is 5m.

[0018] The blasting borehole has a diameter of 94 mm, penetrates the coal seam and extends 1 m into the floor below the coal seam;

[0019] Any four adjacent and rectangularly distributed extraction boreholes in the two rows of extraction boreholes constitute a hole group. The number of hole groups and blasting boreholes is equal and one-to-one corresponding. Any blasting borehole is located at the center of the four rectangularly distributed extraction boreholes in the corresponding hole group.

[0020] The hole section from the bottom of the blasting borehole to 1m above the top of the coal seam is filled with blasting charges;

[0021] Beneficial effects of the present invention:

[0022] After the extraction borehole and blasting borehole are punched, the hole diameter increases. The extraction borehole can be used as a free surface. After the blasting borehole is filled with water, the blasting action can cause the coal seam floor to break and form a network of fractures that are difficult to close. At the same time, it also causes the coal bodies between various boreholes to shift, thus achieving the loosening and permeability enhancement of the coal seam in this area.

[0023] Under the dynamic load of blasting, moisture can enter the relatively small pores and cracks of the coal body, preventing water from clogging the extraction channels and increasing the water content of the coal body. In the later tunnel excavation process, the amount of dust can be significantly reduced, the working environment of the tunnel face is improved, and the water left in the borehole by hydraulic measures can be used to turn waste into treasure. The operation is simple and the permeability-enhancing effect is significant. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1It is a schematic side view of the arrangement of the extraction drilling hole and the blasting drilling hole of the present invention;

[0026] Figure 2 It is a schematic diagram of any hole group and blasting drilling of the present invention;

[0027] Figure 3 It is a schematic diagram of the coal seam fissure morphology after blasting of the present invention. DETAILED DESCRIPTION

[0028] 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.

[0029] like Figures 1 to 3 As shown, a method for eliminating the outburst of a tunnel protruding coal seam 3 by downward drilling and reverse blasting includes the following steps:

[0030] Two rows of downward extraction drilling holes 1 are arranged in parallel on the coal seam 3 step facing the face of the tunnel;

[0031] A row of blasting boreholes 2 arranged in the same direction is opened in the middle of the two rows of extraction boreholes 1, and the blasting boreholes 2 are coaxially arranged with the extraction boreholes 1;

[0032] Perform hydraulic flushing on each extraction borehole 1 and blasting borehole 2;

[0033] Connect the extraction borehole 1 to the extraction pipeline to extract gas;

[0034] A blasting charge column 5 is placed in each blasting borehole 2;

[0035] Water is injected into the blasting borehole 2 until the liquid level is higher than the blasting charge column 5;

[0036] The blasting borehole 2 is sealed, the sealing hole position is above the liquid surface, and the detonation line is led through the sealing hole position to the outside of the blasting borehole 2;

[0037] The blasting columns 5 in each blasting borehole 2 are detonated simultaneously, and the detonated blasting boreholes 2 are connected to the extraction pipeline for gas extraction;

[0038] After the extraction borehole 1 and the blasting borehole 2 are hydraulically punched, the aperture increases; after the blasting charge 5 is placed in the blasting borehole 2 and water is injected, the blasting action can cause the bottom plate 4 of the coal seam 3 to break and form a difficult-to-close fracture network, and also cause the coal bodies between various boreholes to shift, thereby achieving loosening and permeability enhancement of the coal seam 3 in the area, which can improve the permeability between coal and gas, facilitate gas release, reduce gas concentration, and thus reduce the probability of coal and gas outburst accidents;

[0039] Moreover, under the dynamic load of blasting, moisture can enter the relatively small pores and cracks of the coal body, increasing the water content of the coal body. In the later tunnel excavation process, the amount of dust can be significantly reduced, and the working environment of the tunnel face can be improved.

[0040] The diameter of the extraction borehole 1 is 153 mm, and the bottom of the extraction borehole 1 is located at 2 / 3 of the thickness of the coal seam 3; the bottom of the extraction borehole 1 is located at 2 / 3 of the thickness of the coal seam 3, which can effectively improve the efficiency of coal mining, reduce resource waste, ensure the stability of the mine structure, and provide convenience for subsequent operations.

[0041] The two rows of extraction boreholes 1 are symmetrically placed, and the spacing between the two rows of extraction boreholes 1 is 5m; the two rows of symmetrically placed extraction boreholes 1 can be more evenly distributed on the working surface, which is conducive to uniformly extracting gas inside the coal seam 3 and avoiding excessive gas concentration or local accumulation.

[0042] The distance between two adjacent extraction boreholes 1 in each row of extraction boreholes 1 is 5m.

[0043] The aperture of the blasting borehole 2 is 94 mm. The blasting borehole 2 penetrates the coal seam 3 and extends 1 m into the bottom plate 4 below the coal seam 3. The blasting borehole 2 penetrates the coal seam 3 to improve the structure of the coal seam 3, help alleviate local stress concentration, improve the stability of the coal seam 3, and at the same time reduce the gas concentration in the coal seam 3 and reduce the risk of gas explosion.

[0044] Any four adjacent and rectangularly distributed extraction boreholes 1 in the two rows of extraction boreholes 1 constitute a hole group. The number of hole groups and blasting boreholes 2 is equal and corresponds one to one. Any blasting borehole 2 is located at the center of the four rectangularly distributed extraction boreholes 1 in the corresponding hole group; ensure that the blasting charge 5 can cover the area around each extraction borehole 1 on the surrounding side, thereby improving the crushing effect of blasting.

[0045] The hole section from the bottom of the blasting borehole 2 to 1 m above the top surface of the coal seam 3 is filled with blasting columns 5; this can improve the blasting effect, crushing uniformity and mining efficiency of the coal seam 3, and have a positive impact on the release of gas from the coal seam 3 and the reduction of coal dust generation;

[0046] The hole section of the blasting borehole 2 that is 1 m above the top surface of the coal seam 3 is the sealing section 6 .

[0047] Preferably, the blasting borehole 2 is sealed with a capsule sealer; the capsule sealer inserts a capsule filled with a sealing material into the borehole, and then expands the sealing material in the capsule to fill the borehole through pressure or other means, thereby playing a role in sealing and reinforcing;

[0048] The capsule sealer is a preferred method for sealing the holes in this application, and materials such as cannon clay or epoxy resin can also be used for sealing.

[0049] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0050] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A method for eliminating coal outbursts by downward drilling and reverse blasting in tunnel outburst coal seams, characterized in that: The following steps are involved: Two rows of downward extraction drilling holes (1) are arranged side by side on the bench facing the coal seam (3); A row of blasting holes (2) arranged in the same direction is opened in the middle of the two rows of extraction holes (1), and the blasting holes (2) are all arranged coaxially with the extraction holes (1); Performing hydraulic flushing on each extraction borehole (1) and blasting borehole (2); Connecting the extraction borehole (1) to the extraction pipeline to extract gas; A blasting charge column (5) is placed in each blasting borehole (2); Water is injected into the blasting borehole (2) until the liquid level is higher than the blasting charge column (5); The blasting borehole (2) is sealed, the sealing hole position is above the liquid surface, and the detonation line is led through the sealing hole position to the outside of the blasting borehole (2); The blasting columns (5) in each blasting borehole (2) are detonated simultaneously, and the detonated blasting boreholes (2) are connected to a gas extraction pipeline for gas extraction.

2. The method for eliminating coal outbursts by downward drilling and reverse blasting for tunnel outbursts according to claim 1 is characterized in that: The diameter of the extraction borehole (1) is 153 mm, and the bottom of the extraction borehole (1) is located at 2 / 3 of the thickness of the coal seam (3).

3. The method for eliminating coal outbursts by downward drilling and reverse blasting for tunnel outbursts according to claim 2 is characterized in that: The two rows of extraction boreholes (1) are symmetrically arranged, and the spacing between the two rows of extraction boreholes (1) is 5m.

4. The method for eliminating coal outbursts by downward drilling and reverse blasting for tunnel outbursts according to claim 3 is characterized in that: The distance between two adjacent extraction boreholes (1) in each row of extraction boreholes (1) is 5m.

5. The method for eliminating coal outbursts by downward drilling and reverse blasting for tunnel outbursts according to claim 4 is characterized in that: The diameter of the blasting borehole (2) is 94 mm. The blasting borehole (2) penetrates the coal seam (3) and extends to 1 m inside the bottom plate (4) below the coal seam (3).

6. The method for eliminating coal outbursts by downward drilling and reverse blasting for tunnel outbursts according to claim 5 is characterized in that: Any four adjacent and rectangularly distributed extraction boreholes (1) in the two rows of extraction boreholes (1) constitute a borehole group. The number of borehole groups and blasting boreholes (2) is equal and corresponds one to one. Any blasting borehole (2) is located at the center of the four rectangularly distributed extraction boreholes (1) in the corresponding borehole group.

7. The method for eliminating coal outbursts by downward drilling and reverse blasting for tunnel outbursts according to claim 6 is characterized in that: The hole section from the bottom of the blasting borehole (2) to 1 m above the top surface of the coal seam (3) is filled with blasting explosive columns (5).

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