Upward continuous blasting anti-reflection and extraction method for inclined high-gas coal seam of tunnel

Abstract

The invention discloses an upward continuous blasting anti-reflection and extraction method for an inclined high-gas coal seam of a tunnel, and belongs to the field of tunnel gas control. The method comprises the following steps: S1, determining an outburst prevention control boundary of a high-gas coal seam in front of a tunnel face; s2, a first row of large-diameter extraction drill holes located on the uppermost portion of the outburst prevention control boundary are constructed on the tunnel face towards the coal seam, hole sealing operation is carried out, and then an extraction pipeline is connected for gas extraction; s3, a first row of blasting drill holes are constructed in the coal seam on the tunnel face, then blasting explosive columns are loaded into the first row of blasting drill holes, and the first row of blasting drill holes are detonated at the same time; s4, the first row of blasting drill holes are connected with a gas extraction pipeline, and gas extraction is conducted; s5, the steps S2-S4 are repeated, and construction, charging, blasting and extraction operation of the second row of large-diameter extraction drill holes and the second row of blasting drill holes are conducted till the lowest portion of the outburst prevention control boundary is achieved; therefore, the gas extraction effect can be enhanced, and the construction period of tunnel coal uncovering and coal seam crossing is greatly shortened.

Description

Technical Field

[0001] The invention belongs to the field of tunnel gas control, and in particular relates to an upward continuous blasting permeability enhancement and extraction method for an inclined high-gas coal seam in a tunnel. Background Art

[0002] Due to the complexity of geological conditions and the flammable and explosive nature of gas, gas tunnels are prone to accidents such as gas explosions and gas outbursts, which bring huge safety risks. Gas extraction is one of the important technical means of tunnel gas control, but for low-permeability coal seams, the gas extraction effect is poor, and the extraction time to meet the standard is long, which seriously delays the tunnel penetration period.

[0003] Tunnels generally have a tight construction schedule. Once you encounter a high-gas or protruding coal seam, you must use gas extraction measures. If the extraction time is long, it will affect the tunnel construction schedule and even affect the regional highway and railway construction. When selecting a tunnel site, you will generally try to avoid the coal seam, but the actual situation is that the tunnel excavation direction is often oblique to the coal seam, which creates engineering problems for tunnel coal excavation. Tunnel construction requires safe and rapid exposure and crossing of high-gas or protruding coal seams, but traditional coal seam permeability enhancement and extraction methods take a long time and are difficult to meet the construction schedule requirements of tunnel construction.

[0004] In view of the above problems, it is urgent to find a safe and fast permeability enhancement and extraction method for inclined high-gas or protruding coal seams in tunnels. Summary of the invention

[0005] In view of the deficiencies in the prior art, the purpose of the present invention is to provide an upward continuous blasting permeability enhancement and extraction method for inclined high-gas coal seams in tunnels, which solves the problems in the prior art.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] The upward continuous blasting permeability enhancement and extraction method for inclined high-gas coal seams in tunnels includes the following steps:

[0008] S1, determine 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: Construct the first row of large-diameter extraction boreholes at the top of the anti-burst control boundary on the tunnel heading facing the coal seam, seal the boreholes, and then connect the extraction pipeline to extract gas;

[0010] S3, construct the first row of blasting holes facing the coal seam on the tunnel face, then load blasting charges into the first row of blasting holes, seal the holes, and then detonate the first row of blasting holes simultaneously;

[0011] S4, sealing the first row of blasting holes and connecting them to the gas extraction pipeline to extract gas;

[0012] S5, repeat S2-S4, and carry out the construction, charging, blasting and extraction operations of the second row of large-diameter extraction boreholes and the second row of blasting boreholes until the lowest point of the burst prevention control boundary is reached.

[0013] Furthermore, the large-diameter extraction boreholes have a hole spacing of 4 m, a hole diameter of 153 mm, a number of boreholes of 1+L / 4, and the boreholes penetrate the coal seam and enter the roof rock layer 1 m.

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

[0015] Furthermore, the hole spacing of the blasting drilling holes is 4m, the hole diameter is 94mm, the number of drilling holes is L / 4-1, and the drilling holes penetrate the coal seam and enter the roof rock layer 1m.

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

[0017] Furthermore, the charging area of ​​the blasting 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 inclined high-gas coal seams in tunnels according to claim 1 is characterized in that an upward energy-gathering hood is placed under the blasting column.

[0019] The upward continuous blasting permeability enhancement and extraction system for inclined high-gas coal seams in tunnels includes:

[0020] Boundary determination module: determine 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] Drilling and extraction module: Construct the first row of large-diameter extraction boreholes at the top of the anti-blowout control boundary facing the coal seam on the tunnel heading, seal the holes, and then connect the extraction pipeline for gas extraction;

[0022] Drilling and blasting module: construct the first row of blasting holes facing the coal seam on the tunnel face, then load blasting charges into the first row of blasting holes, seal the holes, and then detonate the first row of blasting holes simultaneously;

[0023] Gas extraction module: After sealing the first row of blasting holes, connect the gas extraction pipeline to extract gas;

[0024] Also, repeat the construction module: repeat the contents of the drilling and extraction module, drilling and blasting module and gas extraction module, and carry out the construction, charging, blasting and extraction operations of the second row of large-diameter extraction boreholes and the second row of blasting boreholes until the bottom of the burst control boundary.

[0025] Beneficial effects of the present invention:

[0026] 1. According to the characteristics of inclined coal seams, the present invention adopts a method of blasting from top to bottom and upward layer by layer, which can achieve sufficient loosening and permeability enhancement of the area between the blasting borehole and the extraction borehole, and the blasting effect of subsequent blasting boreholes will cause the coal seam in the upper area to be disturbed again or multiple times, thereby continuously providing a gas extraction effect and greatly shortening the construction period of tunneling coal uncovering and crossing the coal seam.

[0027] 2. The present invention adopts a cross-hole arrangement method for extraction drilling and blasting drilling, and the energy-gathering cover under the blasting column ensures that the blasting energy is transmitted and acts upward, effectively achieving the loosening of the area. The three-dimensional crack network generated by the blasting makes the permeability enhancement and extraction effect better. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] 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.

[0029] Figure 1 It is a schematic diagram of the terminal hole position of the present invention;

[0030] Figure 2 It is a schematic diagram of various drilling arrangements of the present invention;

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

[0032] Figure 4 It is a schematic diagram of the charging position of the blasting column in the blasting borehole of the present invention;

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

[0034] 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.

[0035] Example 1

[0036] The upward continuous blasting permeability enhancement and extraction method for inclined high-gas coal seams in tunnels includes the following steps:

[0037] S1, according to relevant standards and regulations of the tunnel industry, such as "Technical Code for Safety of Tunnel Engineering" (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, constructing the first row of large-diameter extraction boreholes 4 located at the top of the anti-burst control boundary in the coal seam at the tunnel face 2, and sealing the boreholes according to the conventional sealing method, and connecting the extraction pipeline 8 for gas extraction;

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

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

[0041] 1) Clean up the debris around the borehole to ensure the smooth sealing operation, and use the wellhead device to fix the extraction pipeline to ensure its stability during the sealing process;

[0042] 2) Install the sealing device at the borehole opening, ensure that the sealing tube matches the extraction hole, and perform a sealing check;

[0043] 3) Use sealing materials (such as cement slurry, expansive materials) for preliminary plugging, starting from the bottom of the hole and gradually filling in the direction of the hole mouth to ensure that the sealing material evenly fills the hole wall gap. During the sealing process, high-pressure pumping equipment should be used to ensure the density of the sealing material;

[0044] 4) After the sealing material is initially solidified, check the tightness of the hole to prevent leakage. Use a gas detection instrument to monitor the leakage after sealing to ensure that the sealing is qualified;

[0045] 5) After the sealing is completed, the sealing material needs to have enough time to solidify. Cement slurry sealing materials usually require more than 24 hours of solidification time;

[0046] 6) Clean the debris around the hole.

[0047] S3, construct the first row of blasting holes 5 in the coal seam at the tunnel face 2;

[0048] like Figure 2 As shown, the hole spacing of the blasting boreholes 5 is 4m, the hole diameter is 94mm, the number of boreholes is L / 4-1 (take an integer), the boreholes penetrate the coal seam and enter the roof rock layer 1m; and the vertical distance between the end 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, loading blasting charge 6 into the first row of blasting holes 5;

[0050] like Figure 3 to Figure 4 As shown, the charging area is the drilled coal seam section and 1m before and after the coal seam section. An upward energy-gathering cover 7 is placed under the blasting column 6. Its purpose is to gather the explosion energy and thus improve the efficiency of blasting.

[0051] S5, sealing the first row of blasting holes 5, and then simultaneously detonating the first row of blasting holes 5;

[0052] Blasting hole sealing process: clean the gravel and debris in the hole to be sealed; select clay with fine particles and plasticity; determine the starting position and sealing length of the hole; take an appropriate amount of clay and put it into the blasting hole in layers; use a tampering tool to tamper with the first layer of clay; after the sealing is completed, use a tapping air sealing rod to check for looseness and gaps in the hole, and check whether the hole opening is well sealed; clean up the debris around the hole opening to ensure that the sealing material completely covers the hole opening.

[0053] S6, sealing the first row of blasting holes and connecting them to the gas extraction pipeline 8 to extract gas;

[0054] S7, repeat S2-S6, and 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 burst prevention control boundary.

[0055] Example 2

[0056] 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 examples are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this patent.

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

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

[0059] S2, construct the first row of large-diameter extraction boreholes 4 located at the top of the anti-burst control boundary in the coal seam at the tunnel face 2, the hole spacing of the large-diameter extraction boreholes 4 is 4m, the hole diameter is 153mm, the number of boreholes is 15, the boreholes penetrate the coal seam and enter the roof rock layer 1m, and seal the holes according to the conventional sealing method, and connect the extraction pipeline 8 for gas extraction;

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

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

[0062] S5, after the first row of blasting boreholes 5 are charged, all blasting boreholes are sealed according to a conventional sealing method and detonated at the same time; the first row of blasting boreholes 5 are connected to the extraction pipeline 8 to extract gas;

[0063] S6, according to S2-S5, the second row of large-diameter extraction boreholes 4 and the second row of blasting boreholes 5 are constructed, charged, blasted and extracted until the lowest point of the burst prevention control boundary is reached.

[0064] After using this method in the tunnel, the use of special extraction methods in tunnels (such as gas or groundwater extraction) can significantly improve construction safety and efficiency. By reducing gas concentration and reducing the risk of water damage, these methods effectively prevent explosions and landslides, improve air quality and working environment in the tunnel, and reduce downtime. In addition, extraction can reduce rock pressure, prevent rock bursts, maintain the stability of the tunnel structure, extend the service life of the tunnel, and reduce subsequent maintenance costs.

[0065] 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.

[0066] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to 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 increasing permeability and draining coal seams by upward continuous blasting in inclined high-gas coal seams in tunnels, characterized in that: The following steps are involved: S1, determine 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; S2: Construct the first row of large-diameter extraction boreholes at the top of the anti-burst control boundary on the tunnel heading facing the coal seam, seal the boreholes, and then connect the extraction pipeline to extract gas; S3, construct the first row of blasting holes facing the coal seam on the tunnel face, then load blasting charges into the first row of blasting holes, seal the holes, and then detonate the first row of blasting holes simultaneously; S4, sealing the first row of blasting holes and connecting them to the gas extraction pipeline to extract gas; S5, repeat S2-S4, and carry out the construction, charging, blasting and extraction operations of the second row of large-diameter extraction boreholes and the second row of blasting boreholes until the lowest point of the burst prevention control boundary is reached.

2. The upward continuous blasting permeability enhancement and extraction method for inclined high-gas coal seams in tunnels according to claim 1 is characterized in that: The large-diameter extraction boreholes have a hole spacing of 4m, a hole diameter of 153mm, a number of holes of 1+L / 4, and the boreholes penetrate the coal seam and enter the roof rock layer 1m.

3. The upward continuous blasting permeability enhancement and extraction method for inclined high-gas coal seams in tunnels according to claim 1 is characterized in that: The large-diameter extraction borehole uses a high-pressure sealing capsule to seal the hole mouth 8 meters.

4. The upward continuous blasting permeability enhancement and extraction method for inclined high-gas coal seams in tunnels according to claim 1 is characterized in that: The blasting drilling holes have a hole spacing of 4m, a hole diameter of 94mm, a drilling number of L / 4-1, and the drilling holes penetrate the coal seam and enter the roof rock layer 1m.

5. The upward continuous blasting permeability enhancement and extraction method for inclined high-gas coal seams in tunnels according to claim 1 is characterized in that: The vertical distance between the end points of the first row of blasting holes and the first row of large-diameter extraction holes is 4-5m.

6. The upward continuous blasting permeability enhancement and extraction method for inclined high-gas coal seams in tunnels according to claim 1, characterized in that: The charging area of ​​the blasting column is the coal seam section of the blasting borehole and 1m before and after the coal seam section.

7. The upward continuous blasting permeability enhancement and extraction method for inclined high-gas coal seams in tunnels according to claim 1 is characterized in that: An upward-facing energy-focusing shield is placed under the blasting charge column.

8. An upward continuous blasting permeability enhancement and extraction system for inclined high-gas coal seams in tunnels, characterized in that: include: Boundary determination module: determine 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; Drilling and extraction module: Construct the first row of large-diameter extraction boreholes at the top of the anti-blowout control boundary facing the coal seam on the tunnel heading, seal the holes, and then connect the extraction pipeline for gas extraction; Drilling and blasting module: construct the first row of blasting holes facing the coal seam on the tunnel face, then load blasting charges into the first row of blasting holes, seal the holes, and then detonate the first row of blasting holes simultaneously; Gas extraction module: After sealing the first row of blasting holes, connect the gas extraction pipeline to extract gas; Also, repeat the construction module: repeat the contents of the drilling and extraction module, drilling and blasting module and gas extraction module, and carry out the construction, charging, blasting and extraction operations of the second row of large-diameter extraction boreholes and the second row of blasting boreholes until the bottom of the burst control boundary.

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