CN102900460B - Method for performing through-going seam cutting, pressure relief, permeability enhancement and quick tunneling on soft and high-outburst coal seam - Google Patents

Abstract

The invention relates to a method for pressure relief and permeability enhancement and rapid excavation through bed-cutting slots in soft and high outburst coal seams, which is especially suitable for rapid excavation in coal mines with strong outburst risks and difficult support coal seams. A network-type fracture network is formed by adopting high-pressure jet slotting pressure-relief and anti-reflection technology to strengthen the gas extraction effect of the strip coal seam in the pre-drainage coal roadway through the bed drilling; and the network filling area is formed by injecting filling materials to improve the coal mass The strength and stress distribution make the maintenance easier in the coal roadway excavation process, and at the same time reduce the gas gushing to the excavation roadway, and finally eliminate the gas disaster in the excavation process, and achieve the purpose of safe and rapid excavation.

Description

Pressure Relief and Enhanced Permeability and Rapid Excavation Method of Cutting Slits in Soft and High Outburst Coal Seam

technical field

The invention relates to a rapid excavation method, in particular to a rapid excavation method applicable to soft and high outburst coal seams with strong outburst risks and difficult support coal seams in coal mines.

Background technique

The mining of soft and high outburst coal seams is accompanied by a large amount of gas gushing out, and the outburst threat is greater, and the soft coal quality makes it difficult to support coal roadways, which seriously restricts the safe and rapid production of mines. At present, when the protective layer cannot be exploited, the gas problem in the process of excavating the high outburst coal seam is mainly solved by pre-extracting coal seam gas. However, the conventional gas drainage method has a small effective range of gas drainage in a single hole and a large drilling workload. Moreover, the low extraction efficiency cannot effectively solve the gas hazard during the excavation process. Due to the soft coal quality and high pressure during the coal roadway excavation, roadway maintenance is very difficult, a lot of manpower and material resources are wasted, the progress of the project is affected, and the mining imbalance is caused.

Contents of the invention

Technical problem: The purpose of the present invention is to solve the problems existing in the prior art, and to provide a soft and high outburst coal seam piercing slotting pressure relief and rapid tunneling method, through the use of floor piercing drilling and high-pressure jet slotting to relieve pressure Anti-reflection technology forms a network of fracture networks to enhance the extraction effect of coal seam gas in the coal seam pre-drainage roadway through seam drilling; and forms a network filling area through pressure injection of filling materials to improve the strength of the coal body around the coal seam roadway and stress distribution, making the maintenance easier during the coal roadway excavation process, eliminating gas disasters during the excavation process, and thus realizing safe and rapid excavation.

Technical solution: The method for pressure relief and rapid excavation of the soft and high outburst coal seam by piercing slits of the present invention includes arranging bottom extraction roadways along the working face in the coal seam floor strata, arranging drilling sites in the bottom pumping roadways, and pumping from the bottom In each drilling site of the roadway, construct a layer-penetrating slit hole in the direction of the coal seam until the coal seam is passed through, perform high-pressure hydraulic slits in the coal seam, and then implement gas drainage; it is characterized in that it also includes the following steps:

a. In the bottom pumping roadway, a plurality of drilling sites with a spacing of 6 to 8 m are arranged, and each drilling site is arranged with 5 to 7 bed-crossing slotted holes distributed linearly in the coal seam. Hole spacing is 6~8m;

b. 30 to 50 days before the excavation time of the coal seam roadway, stop gas drainage for a row of seam-penetrating slotted holes near the two sides of the pre-excavated coal seam roadway, and use a grouting pump to stop gas drainage for a row of seam-penetrating slot holes. Filling materials are sequentially injected into the cracks to reinforce the coal bodies on both sides of the pre-excavated coal seam roadway;

c. Continue gas drainage for unfilled perforated slotted holes;

d. 5 to 7 days before the excavation time of the coal seam roadway, check the effect of gas drainage. After meeting the requirements of the "Regulations on the Prevention and Control of Coal and Gas Outburst", the coal seam roadway can be excavated according to the conventional method at the time of coal seam roadway excavation;

e. During the process of excavating the coal seam roadway, continue to press and inject filling materials into a row of layer-penetrating slotted holes close to the two sides of the pre-excavated coal seam roadway to ensure that the positions of the two rows of layer-penetrating slotted holes filled in sequence should be ahead of the excavation head Not less than 50m.

The number of perforated slotted holes in each drilling site is determined according to the dip angle of the coal seam and the influence radius of the perforated slotted holes.

When the coal seam roadway starts to be excavated, the coal body reinforcement distance needs to exceed 50m.

Beneficial effects: the present invention uses the high-pressure jet slits in the bed-crossing drilling holes of the coal mine floor rock roadway to relieve the pressure and increase the permeability of the high outburst coal seam, improve the gas extraction effect of the strip coal seam gas in the coal seam pre-extraction coal roadway through the bedrock drilling, and eliminate the gas in the coal seam. The high gas gradient reduces the amount of gas gushing out during coal seam roadway excavation and increases the speed of coal seam roadway excavation; and through injection of filling materials, a network filling area is formed to increase the strength of the coal body and improve the support conditions for coal seam roadway excavation , reduce the gushing of gas from the two sides of the coal roadway to the tunneling roadway, while eliminating the outburst danger of high outburst coal roadway excavation, solve the problem of difficult coal roadway support, and greatly increase the speed of coal roadway excavation in soft high outburst coal seams. The invention can increase the concentration of gas drainage in soft and high outburst coal seams by 10-15%, increase the rate of pre-pumping by 25%, and the coal output per hole can reach more than 3 tons; the number of drilling holes required for pre-pumping can be reduced by 20%-30%, The time required for pumping is reduced by 20%; it has excellent promotional value.

Description of drawings

Fig. 1 is a schematic diagram of the rapid tunneling structure of the soft high outburst coal seam of the present invention;

Fig. 2 is a schematic cross-sectional view of A-A of Fig. 1;

In the figure: 1-coal seam, 2-coal seam roadway, 3-bottom pumping roadway, 4-through-layer slotted hole, 5-network filling area, H1-control distance outside the roadway upper side contour, H2-roadway lower side contour Off-line control distance, α-coal seam dip angle.

Detailed ways

An embodiment of the present invention will be further described below in conjunction with accompanying drawing:

As shown in Figure 1, the soft and high outburst coal seam piercing slit pressure relief and rapid tunneling method of the present invention, at first according to the geological information parameters: coal seam thickness, coal seam dip angle α, coal seam direction, gas parameters, hydrological conditions and others There are required parameters in the construction, and a detailed implementation plan is formulated. Do a good job in the preparatory work before implementation, and consider dealing with cracks, faults, water and other risk factors. Arrange the bottom pumping roadway 3 along the direction of the working face in the floor rock layer of the coal seam 1, and determine the influence radius of the slot hole through the slotting test; after completion, arrange a drilling site every 6~8m in the bottom pumping 5~7 bed-through slotted holes 4, the slotted holes are distributed linearly in the coal seam, and the distance between the final holes is 6~8m. According to the coal seam dip angle α and the influence radius of the slotted hole, determine the number of slotted holes for each drilling site, where the inclined and steep coal seam dip angle α is between 25o and 90o, and the control distance outside the roadway upper side contour line is at least H1 The outer control distance H2 of the roadway lower side contour line is 20m, the outer control distance H2 of the roadway lower side contour line is at least 10m, and the outer control distance H1 of the roadway upper side contour line and the outer control distance of the roadway lower side contour line of the gently inclined, near-horizontal coal seam dip angle α between 0o and 25o H2 is at least 15m. If the coal seam is a gently inclined or near-horizontal coal seam, the width of the coal seam roadway 2 is 4m, and the influence radius of the slot hole is 3.7m, the distance to be controlled is 34m, and the control distance of 37m can be controlled by arranging 5 through-layer slot holes 4, and the control distance is greater than 34m , so it is enough to arrange 5 slotted holes 4 through the seam (one is arranged in the coal seam roadway 2, and two are arranged on the upper side and the lower side respectively); if the coal seam is inclined or steeply inclined, the width of the coal seam roadway 2 is 4m, and the slotted If the hole influence radius is 3.3m, the distance to be controlled is 34m. Arranging 6 perforated slotted holes 4 can control 39.6m, and the control distance is greater than 34m. Therefore, it is enough to arrange 6 perforated slotted holes 4 (coal seam roadway 2 1 in the middle, 3 in the upper and 2 in the lower). From each drilling site of the bottom pumping roadway 3 to the direction of the coal seam 1, the seam penetration slot hole 4 is constructed until the coal seam 1 is passed through, and the coal seam 1 is subjected to high-pressure hydraulic slotting, and then the gas drainage is implemented; the coal seam roadway 2 is excavated 30 to 50 days before the time, stop gas drainage for a row of bed-through slotted holes 4 near the two sides of the pre-excavation coal seam roadway 2, and use a grouting pump to fill the row of bed-through slotted holes 4 where gas drainage is stopped. Filling materials are injected sequentially to reinforce the coal bodies on both sides of the pre-excavated coal seam roadway, and the other unfilled layer-penetrating slotted holes 4 continue to extract gas. When the filling materials solidify, a network filling area is formed on both sides of the coal seam roadway 2 5. As shown in Figure 2, the network filling area 5 can increase the strength of the coal body, improve the stress distribution of the coal body, and at the same time prevent the gas outside the network filling area 5 from gushing to the pre-excavation position of the coal seam roadway 2. 5-7 days before the excavation time of the coal seam roadway, check the effect of gas drainage. After meeting the requirements of the "Regulations on the Prevention and Control of Coal and Gas Outburst", excavate the coal seam roadway 2 according to the conventional method at the time of coal seam roadway 2 excavation. At this time, the coal body is reinforced The distance needs to be more than 50m. During the process of excavating the coal seam roadway 2, continue to press and inject filling materials into a row of layer-penetrating slotted holes 4 near the two sides of the pre-excavated coal seam roadway 2 to ensure that the positions of the two rows of layer-penetrating slotted holes 4 to be filled in sequence should be ahead of each other. The tunneling head is not less than 50m.

Claims (1)

1. A method for pressure relief and rapid excavation of soft and high-outburst coal seams through slotting slots, including arranging bottom extraction roads (3) along the direction of the working face in the coal seam (1) floor rock layer, and in the bottom suction roadway (3) Drilling sites are arranged, and the layer-penetrating slotted holes (4) are constructed from each drilling site of the bottom pumping roadway (3) to the direction of the coal seam (1) until the coal seam (1) is passed through, and high-pressure hydraulic pressure is applied to the coal seam (1). slotting, and then implement gas drainage; it is characterized in that it also includes the following steps: a. Arrange a plurality of drilling sites with a spacing of 6-8m in the bottom pumping roadway (3), and each drilling site arranges 5-7 layer-crossing slotted holes (4) that are linearly distributed in the coal seam (1) ), the distance between the final holes of the perforated slotted holes (4) is 6-8m; the number of perforated slotted holes (4) in each drilling site depends on the coal seam inclination angle α and the number of perforated slotted holes (4) The influence radius is determined; the control distance H1 outside the roadway upper side contour line is at least 20m for inclined and sharply inclined coal seam dip angle α between 25o and 90o, and the control distance H2 outside the roadway lower side contour line is at least 10m; gentle slope, near horizontal The coal seam dip angle α is between 0o and 25o, and the control distance H1 outside the roadway upper side contour line and the outer control distance H2 outside the roadway lower side contour line are at least 15m; b. 30 to 50 days before the excavation time of the coal seam roadway (2), stop the gas drainage for a row of perforated slot holes (4) on both sides of the pre-excavated coal seam roadway (2), and stop the gas drainage through the grouting pump Filling materials are sequentially injected into a row of through-bed slotted holes (4) for gas drainage to reinforce the coal bodies on both sides of the pre-excavated coal seam roadway (2); c. Continue gas drainage for unfilled perforated slotted holes (4); d. 5 to 7 days before the excavation time of the coal seam roadway (2), check the effect of gas drainage. After meeting the requirements of the "Regulations on the Prevention and Control of Coal and Gas Outburst", the coal seam can be excavated according to the conventional method during the coal seam roadway (2) excavation time Roadway (2); the coal body reinforcement distance on both sides of the coal seam roadway (2) must exceed 50m; e. During the process of excavating the coal seam roadway (2), continue to press and inject filling materials into the row of perforated slot holes (4) on both sides of the pre-excavated coal seam roadway (2) in order to ensure that the two rows of perforated holes filled in sequence The position of the layer slot hole (4) should be no less than 50m ahead of the tunneling head.