Upward continuous blasting permeability enhancement and extraction method for tunnel inclined high-gas coal seam

Abstract

The application discloses a method for upward continuous blasting permeability enhancement and extraction of a tunnel inclined high-gas coal seam and belongs to the field of tunnel gas control. The method comprises the following steps: S1, determining a outburst prevention control boundary of a high-gas coal seam in front of a tunnel face; S2, constructing a first row of large-diameter extraction boreholes located at the uppermost part of the outburst prevention control boundary on the coal seam at the tunnel face, and performing hole sealing operation, and then connecting an extraction pipeline to perform gas extraction; S3, constructing a first row of blasting boreholes on the coal seam at the tunnel face, then loading blasting columns into the first row of blasting boreholes, and simultaneously initiating the first row of blasting boreholes; S4, connecting the first row of blasting boreholes with the gas extraction pipeline to perform gas extraction; and S5, repeating S2-S4 to perform construction, charging, blasting and extraction operation of a second row of large-diameter extraction boreholes and a second row of blasting boreholes until the lowermost part of the outburst prevention control boundary, so that the gas extraction effect can be enhanced, and the construction period of the tunnel coal uncovering and coal seam crossing can be greatly shortened.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of tunnel gas control, and particularly relates to an upward continuous blasting permeability improvement and extraction method for a tunnel inclined high-gas coal seam. BACKGROUND

[0002] Due to the complexity of geological conditions and the flammable and explosive characteristics of gas, gas explosions and gas outbursts are prone to occur in gas tunnels, bringing huge safety risks. Gas extraction is one of the important technical means for tunnel gas control, but for low-permeability coal seams, the gas extraction effect is poor, the extraction standard time is long, and the tunnel through period is seriously delayed.

[0003] The tunnel generally has a tight construction period. Once high-gas or outburst coal seams are encountered, gas extraction measures must be taken. If the extraction time is long, it will affect the tunnel through period, and even affect the construction of highways and railways in the area. When selecting a tunnel site, coal seams are generally avoided as much as possible, but in actual situations, the tunnel excavation direction often intersects with coal seams, forming a tunnel coal uncovering engineering problem. Tunnel construction requires safe and rapid uncovering and crossing of high-gas or outburst coal seams, but the traditional coal seam permeability improvement and extraction method requires a long time and is difficult to meet the construction period requirements of the tunnel.

[0004] In view of the above problems, it is urgent to find a safe and rapid permeability improvement and extraction method for tunnel inclined high-gas or outburst coal seams. SUMMARY

[0005] In view of the deficiencies of the prior art, the purpose of the present application is to provide an upward continuous blasting permeability improvement and extraction method for a tunnel inclined high-gas coal seam, which solves the problems in the prior art.

[0006] The purpose of the present application can be achieved by the following technical solutions:

[0007] The upward continuous blasting permeability improvement and extraction method for a tunnel inclined high-gas coal seam comprises the following steps:

[0008] S1, determining the outburst prevention control boundary of the high-gas coal seam in front of the tunnel face, with a vertical length of H and a horizontal length of L;

[0009] S2, constructing a first row of large-diameter extraction drill holes at the uppermost part of the outburst prevention control boundary in the coal seam in front of the tunnel face, and performing hole sealing, and then connecting the extraction pipeline for gas extraction;

[0010] S3, constructing a first row of blasting drill holes in the coal seam in front of the tunnel face, then loading blasting columns into the first row of blasting drill holes, then sealing the holes, and then simultaneously initiating the first row of blasting drill holes;

[0011] S4, connecting the gas extraction pipeline after sealing the first row of blasting boreholes, and performing gas extraction;

[0012] S5, repeating S2-S4 to perform the construction, charging, blasting and extraction operation of the second row of large-diameter extraction boreholes and the second row of blasting boreholes until the lowermost part of the outburst prevention control boundary.

[0013] Further, the hole spacing of the large-diameter extraction borehole is 4m, the hole diameter is 153mm, and the number of boreholes is 1+L / 4. The borehole penetrates the coal seam and enters the roof rock layer by 1m.

[0014] Further, the large-diameter extraction borehole uses a high-pressure sealing capsule to seal the hole mouth for 8m.

[0015] Further, the hole spacing of the blasting borehole is 4m, the hole diameter is 94mm, and the number of boreholes is L / 4-1. The borehole penetrates the coal seam and enters the roof rock layer by 1m.

[0016] Further, the vertical distance between the terminal points of the first row of blasting boreholes and the first row of large-diameter extraction boreholes is 4-5m.

[0017] Further, the charging area of the blasting explosive column is the coal seam section of the blasting borehole and 1m before and after the coal seam section.

[0018] 7. The upward continuous blasting permeability enhancement and extraction method for a tunnel inclined high-gas coal seam according to claim 1, characterized in that an upward energy-gathering cover is placed below the blasting explosive column.

[0019] The upward continuous blasting permeability enhancement and extraction system for a tunnel inclined high-gas coal seam comprises:

[0020] The boundary determination module determines the outburst prevention control boundary of the high-gas coal seam in front of the tunnel face, with a vertical length of H and a horizontal length of L.

[0021] The borehole extraction module constructs a first row of large-diameter extraction boreholes at the uppermost part of the outburst prevention control boundary in the coal seam in front of the tunnel face, performs sealing operation, and then connects the extraction pipeline to perform gas extraction.

[0022] The borehole blasting module constructs a first row of blasting boreholes in the coal seam in front of the tunnel face, then loads a blasting explosive column in the first row of blasting boreholes, performs sealing, and simultaneously initiates the first row of blasting boreholes.

[0023] The gas extraction module connects the gas extraction pipeline after sealing the first row of blasting boreholes, and performs gas extraction.

[0024] And, repeat construction module: repeat the content of drilling and extraction module, drilling and blasting module and gas extraction module, carry out the construction, charging, blasting and extraction operation of the second row of large-diameter extraction drillings and the second row of blasting drillings, until the lowermost part of the outburst control boundary.

[0025] The beneficial effects of the present application are:

[0026] 1. According to the characteristics of the inclined coal seam, the present application adopts the way of top-down and layer-by-layer upward blasting, which can realize the full loosening and permeability enhancement of the area between the blasting drillings and the extraction drillings, and the blasting effect of the subsequent blasting drillings will disturb the upper area of the coal seam again or multiple times, thereby continuously providing the gas extraction effect and greatly shortening the tunnel coal uncovering and coal seam crossing period.

[0027] 2. The present application adopts the cross-hole drilling method for the extraction drillings and the blasting drillings, and the energy-gathering cover under the blasting charge ensures the upward transmission and effect of the blasting energy, effectively realizing the loosening of the area, and the three-dimensional fracture network generated by blasting makes the permeability extraction effect better. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description, and obviously, other drawings can also be obtained by those skilled in the art without creative labor.

[0029] Figure 1 is a final hole position schematic diagram of the present application;

[0030] Figure 2 is a schematic diagram of various drillings of the present application;

[0031] Figure 3 is a schematic diagram of the spatial position of the energy-gathering cover and the blasting charge of the present application;

[0032] Figure 4 is a schematic diagram of the charging position of the blasting charge in the blasting drilling of the present application;

[0033] In the figure: 1-tunnel surrounding rock, 2-tunnel face, 3-high-gas coal seam, 4-large-diameter extraction drilling, 5-blasting drilling, 6-blasting charge, 7-energy-gathering cover, 8-extraction pipeline. DETAILED DESCRIPTION

[0034] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0035] Embodiment 1

[0036] The upward continuous blasting permeability improvement and extraction method for a tunnel inclined high-gas coal seam comprises the following steps:

[0037] S1, according to the relevant specifications and regulations of the tunnel industry, such as “Tunnel Engineering Safety Technical Regulations” (GB / T 50450-2017), determine the outburst prevention control boundary of the high-gas coal seam 3 in front of the tunnel face 2, with a vertical length of H and a horizontal length of L;

[0038] S2, at the tunnel face 2, construct the first row of large-diameter extraction drill holes 4 located at the uppermost part of the outburst prevention control boundary, and perform hole sealing operation according to the conventional hole sealing method, and connect the extraction pipeline 8 for gas extraction;

[0039] As shown in Figure 2 , the hole spacing of the large-diameter extraction drill hole 4 is 4m, the hole diameter is 153mm, the number of drill holes is 1+L / 4 (integer), and the drill hole penetrates the coal seam and enters the roof rock layer 1m,

[0040] The steps of the conventional hole sealing method are specifically as follows:

[0041] 1) Clean the sundries around the drill hole opening to ensure smooth hole sealing operation, and use the wellhead device to fix the extraction pipeline to ensure its stability during the hole sealing process;

[0042] 2) Install the hole sealing device at the drill hole opening to ensure that the hole sealing pipe matches the extraction hole and perform sealing inspection;

[0043] 3) Use hole sealing materials (such as cement slurry, expandable material) to perform preliminary plugging, starting from the bottom of the hole and gradually filling towards the hole opening, to ensure that the hole sealing materials uniformly fill the gap between the hole walls. During the hole sealing process, high-pressure pumping equipment should be used to ensure the compactness of the hole sealing materials;

[0044] 4) After the hole sealing materials are initially solidified, perform in-hole sealing inspection to prevent gas leakage, use gas detection instruments to monitor the gas leakage after hole sealing, and ensure that the sealing property is qualified;

[0045] 5) After completing the hole sealing, the hole sealing materials need to have sufficient time for solidification. The cement slurry hole sealing material usually needs more than 24 hours for solidification;

[0046] 6) Clean up debris around the opening.

[0047] S3, the first row of blasting boreholes 5 is constructed in the coal seam at the tunnel face 2;

[0048] like Figure 2 As shown, the spacing between the blasting boreholes 5 is 4m, the diameter is 94mm, the number of boreholes is L / 4-1 (rounded to the nearest integer), the boreholes penetrate the coal seam and enter the roof strata by 1m; and the vertical distance between the final hole points of the first row of blasting boreholes 5 and the first row of large-diameter extraction boreholes 4 is 4-5m.

[0049] S4, Explosive charge 6 is loaded into the first row of blasting boreholes 5;

[0050] like Figures 3-4 As shown, the charging area is the drilled coal seam section and 1m before and after the coal seam section. An upward-facing shaped charge 7 is placed below the explosive charge 6. Its purpose is to concentrate the explosive energy, thereby improving the blasting efficiency.

[0051] S5, seal the first row of blasting boreholes 5, and then detonate the first row of blasting boreholes 5 simultaneously;

[0052] Blasting hole sealing process: Clean the gravel and debris from the hole to be sealed; select fine-grained, plastic clay; determine the starting position and length of the sealing; place an appropriate amount of clay in layers into the blasting hole; use a tamping tool to tamp the first layer of clay; after sealing, use a light tapping air sealing rod to check for looseness and gaps in the hole and to check if the hole opening is well sealed; clean the debris around the hole opening to ensure that the sealing material completely covers the hole opening.

[0053] S6, after sealing the first row of blasting boreholes, connect the gas extraction pipeline 8 to perform gas extraction;

[0054] S7. Repeat S2-S6 to carry out the construction, charging, blasting and extraction operations of the second row of large-diameter extraction boreholes 4 and the second row of blasting boreholes 5 until the lowest point of the anti-outburst control boundary.

[0055] Example 2

[0056] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described examples are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this patent.

[0057] In this embodiment, taking a tunnel construction area as an example, we will illustrate the upward continuous blasting permeability enhancement and extraction method for inclined high-gas coal seams in tunnels. The specific steps are as follows:

[0058] S1, according to tunnel industry related specifications and regulations, determine the outburst prevention control boundary of the high-gas coal seam 3 in front of the tunnel face 2, the vertical direction length H is 40 meters, and the horizontal direction length L is 60 meters;

[0059] S2, at the tunnel face 2, a first row of large-diameter extraction boreholes 4 is constructed in the coal seam at the uppermost part of the outburst prevention control boundary, the hole spacing of the large-diameter extraction boreholes 4 is 4 m, the hole diameter is 153 mm, the number of boreholes is 15, the boreholes penetrate the coal seam and enter the roof rock layer 1 m, and the boreholes are sealed according to the conventional sealing method, and the extraction pipeline 8 is connected for gas extraction;

[0060] S3, at the tunnel face 2, a first row of blasting boreholes 5 is constructed in the coal seam, the hole spacing of the blasting boreholes 5 is 4 m, the hole diameter is 94 mm, the number of boreholes is 15, the boreholes penetrate the coal seam and enter the roof rock layer 1 m, and the vertical distance between the terminal points of the first row of blasting boreholes and the first row of large-diameter extraction boreholes is 4 m;

[0061] S4, the blasting charge 6 is loaded into the first row of blasting boreholes 5, the charging area is the coal seam section and the 1 m section before and after the coal seam section, and the energy-gathering cover 7 is placed below the blasting charge 6 with the opening facing upward;

[0062] S5, after the first row of blasting boreholes 5 is charged, all the blasting boreholes are sealed according to the conventional sealing method, and are simultaneously detonated; the first row of blasting boreholes 5 is connected to the extraction pipeline 8 for gas extraction;

[0063] S6, according to S2-S5, the construction, charging, blasting and extraction operations of the second row of large-diameter extraction boreholes 4 and the second row of blasting boreholes 5 are performed until the lowermost part of the outburst prevention control boundary.

[0064] After the method is used in the tunnel, the use of special extraction methods (such as gas or underground water extraction) in the tunnel can significantly improve the construction safety and efficiency. By reducing the gas concentration and reducing the risk of water damage, these methods effectively prevent explosion and collapse accidents, improve the air quality and working environment in the tunnel, and reduce the downtime. In addition, extraction can also reduce the rock pressure, prevent rock burst, maintain the stability of the tunnel structure, prolong the service life of the tunnel, and reduce the maintenance cost in the later period.

[0065] In the description of the present specification, the description referring to the terms "one embodiment", "example", "specific example" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0066] The foregoing is considered as illustrative only of the principles of the application. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the application to the exact construction and practice described. Accordingly, all such variations and modifications are intended to be included within the scope of the application as defined in the following claims.

Claims

1. A method for increasing permeability and extraction by upward continuous blasting in tunneling inclined high-gas coal seams, characterized in that, The method comprises the following steps: S1, determining a control boundary of outburst prevention of a high-gas coal seam in front of a tunnel face, the length in vertical direction being H and the length in horizontal direction being L; S2, drilling a first row of large-diameter extraction boreholes in the coal seam in front of the tunnel face, the boreholes penetrating the coal seam and entering a roof rock layer by 1 m, and performing hole sealing, and then connecting an extraction pipeline to extract gas; S3, drilling a first row of blasting boreholes in the coal seam in front of the tunnel face, the boreholes penetrating the coal seam and entering the roof rock layer by 1 m, the vertical distance between the terminal points of the first row of blasting boreholes and the first row of large-diameter extraction boreholes being 4-5 m, then loading blasting columns in the first row of blasting boreholes, the loading area of the blasting columns being the coal seam section of the blasting boreholes and 1 m before and after the coal seam section, then performing hole sealing, and simultaneously initiating the first row of blasting boreholes; S4, connecting the extraction pipeline to extract gas after the hole sealing of the first row of blasting boreholes; S5, repeating S2-S4 to perform the drilling, loading, blasting and extraction of a second row of large-diameter extraction boreholes and a second row of blasting boreholes until the lowermost part of the control boundary of outburst prevention.

2. The upward continuous blasting permeability increasing and extraction method for tunnel inclined high-gassy coal seams according to claim 1, characterized in that, The hole spacing of the large-diameter extraction boreholes is 4 m, the hole diameter is 153 mm, and the number of boreholes is 1+L / 4.

3. The method for upward continuous blasting permeability enhancement and extraction of inclined high-gas coal seams in tunnels according to claim 1, characterized in that, The large-diameter extraction boreholes are sealed by high-pressure hole sealing capsules for 8 m.

4. The upward continuous blasting permeability increasing and extraction method for tunnel inclined high-gassy coal seams according to claim 1, characterized in that, The hole spacing of the blasting boreholes is 4 m, the hole diameter is 94 mm, and the number of boreholes is L / 4-1.

5. The upward continuous blasting permeability increasing and extraction method for tunnel inclined high-gassy coal seams according to claim 1, characterized in that, An upward energy-gathering cover is placed below the blasting column.

6. A system for increasing permeability and extraction of a tunnel inclined high gas coal seam by upward continuous blasting, characterized in that the method of any one of claims 1-5 is performed, wherein, The method comprises: a boundary determination module for determining a control boundary of outburst prevention of a high-gas coal seam in front of a tunnel face, the length in vertical direction being H and the length in horizontal direction being L; a borehole extraction module for drilling a first row of large-diameter extraction boreholes in the coal seam in front of the tunnel face, and performing hole sealing, and then connecting an extraction pipeline to extract gas; a borehole blasting module for drilling a first row of blasting boreholes in the coal seam in front of the tunnel face, then loading blasting columns in the first row of blasting boreholes, and then performing hole sealing, and simultaneously initiating the first row of blasting boreholes; a gas extraction module for connecting the extraction pipeline to extract gas after the hole sealing of the first row of blasting boreholes; and a repeated construction module for repeating the contents of the borehole extraction module, the borehole blasting module and the gas extraction module to perform the drilling, loading, blasting and extraction of a second row of large-diameter extraction boreholes and a second row of blasting boreholes until the lowermost part of the control boundary of outburst prevention.

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