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CN-122014329-A - Spraying type gas extraction plugging method for gob-side entry retaining wall

CN122014329ACN 122014329 ACN122014329 ACN 122014329ACN-122014329-A

Abstract

The invention provides a spraying type gas extraction plugging method for a gob-side entry retaining wall, and belongs to the technical field of gas extraction plugging. The method comprises the steps of precisely positioning a gas main enrichment area and a seepage channel through gas multipoint flow measurement and three-dimensional ground penetrating radar scanning, arranging main and auxiliary extraction pipes and dendritic diversion grooves to form an extraction network, arranging pressure relief holes to balance gas pressure, anchoring and reinforcing an edge weak area to form a surrounding rock-wall integrated reinforcing area, adopting a layered spraying process, combining pressure gradient regulation and control to directionally displace gas to the extraction network, and filling compaction diversion grooves through reverse grouting to seal the extraction pipes after a sprayed layer reaches the standard, so that integral sealing is completed. According to the invention, through the whole process connection of extraction, displacement, blocking and reinforcement, the gas extraction efficiency and blocking durability are improved, the safety risk is avoided, the stability of the wall body is enhanced, the treatment cost is reduced, and a reliable technical support is provided for safe and efficient mining of gob-side entry retaining.

Inventors

  • JIA ZHAO
  • SHI XIAOLIANG
  • GUO JIWEI

Assignees

  • 山西浩博瑞新材料有限公司

Dates

Publication Date
20260512
Application Date
20260414

Claims (10)

  1. 1. The spraying type gas extraction plugging method for the gob-side entry retaining wall body is characterized by comprising the following steps of: S1, carrying out gas seepage and rock mass characteristic detection on a wall to be constructed in an gob-side entry retaining way, positioning a gas main enrichment area and a seepage channel, embedding a main extraction pipe in the surface of the wall, arranging a dendritic diversion trench along the seepage direction by taking the main extraction pipe as the center, and communicating with an auxiliary extraction hole as an auxiliary extraction pipe to form a gas directional extraction network; S2, forming an anchoring spraying hole in a weak area at the edge of the roadway wall body, which is in contact with the surrounding rock, and injecting an anchoring type polymer cementing material to form a surrounding rock-wall body integrated reinforcing band, so that a gas extraction state of an extraction network is maintained in construction; s3, adopting a layered spraying process between the reinforcing belt and the wall core area, gradually pushing spraying from the periphery to the core area, and directionally driving gas to a drainage network for centralized drainage by regulating and controlling spraying pressure and material diffusion parameters; and S4, after the sprayed layer reaches the design strength, performing reverse grouting and plugging on the main extraction pipe and the auxiliary extraction pipe, and simultaneously filling the compaction diversion trench with a foaming plugging material to complete gas extraction and integral plugging of the gob-side entry retaining wall.
  2. 2. The method for spraying type gas extraction and blocking along gob-side entry retaining wall according to claim 1, wherein in step S1, a mode of combining gas multipoint flow measurement with three-dimensional ground penetrating radar scanning is adopted, and a gas seepage judgment formula is adopted Determining a main enrichment zone of gas, wherein Is the gas seepage velocity of the gas, For the gas emission quantity of the measuring point, In order to detect the effective area of the cross section, And positioning a gas main seepage channel by combining an inversion algorithm, and arranging a main extraction pipe at the position.
  3. 3. The gob-side entry retaining wall spraying type gas extraction plugging method according to claim 1, wherein in the step S1, the number of branched guide grooves is 48, the guide grooves are in a global communication structure with a main extraction pipe and auxiliary extraction holes, the width of the guide grooves is 80-120 mm, the depth is 50-80 mm, the distance between adjacent guide grooves is 0.8-1.5 m, the auxiliary extraction holes are symmetrically arranged on two sides of a single guide groove in two rows, the hole distance between adjacent auxiliary extraction holes on the same side is 0.8-1.5 m, the auxiliary extraction holes on two sides are staggered in a regular triangle, namely, a single auxiliary extraction hole on one side of the guide groove is opposite to the central point position of two adjacent auxiliary extraction holes on the opposite side, and the central connecting lines of the three form an equilateral triangle.
  4. 4. The gob-side entry retaining wall spraying type gas extraction plugging method according to claim 1, wherein in step S2, the effective thickness of a reinforcing band in the direction vertical to the surface of a wall is 1.0-2.5 m, the initial setting time of an anchoring type polymer cementing material is less than or equal to 1h, the bonding shear strength with surrounding rock after curing is more than or equal to 2.0MPa, and the gas concentration of a weak band is controlled below 0.5% through an extraction network in construction.
  5. 5. The spraying type gas extraction plugging method for the gob-side entry retaining wall body is characterized in that in the step S1, a plurality of pressure relief holes are formed in the surface of the wall body to balance gas pressure, in the step S3, the pressure relief holes are used as auxiliary spraying holes, spraying branch pipes with atomizing spray heads are arranged, the diameter of each spraying branch pipe is 30-60 mm smaller than that of each pressure relief hole, and the atomizing angle of each spray head is 60-90 degrees.
  6. 6. The gob-side entry retaining wall spraying type gas extraction plugging method according to claim 1, wherein in step S3, gas directional driving is realized by optimizing a spraying pressure gradient, and the pressure gradient is expressed by the formula Regulation and control, wherein In order to achieve a spray pressure differential, the spray pressure, Is the gas permeability coefficient of the rock mass of the wall body, Is the dynamic viscosity of the gas, For the purpose of spraying the displacement distance, Is the equivalent diameter of the seepage channel, Is the gas seepage velocity.
  7. 7. The gob-side entry retaining wall spraying type gas extraction plugging method according to claim 1 is characterized in that in the steps S2 and S3, the distance between adjacent anchoring spraying holes and auxiliary spraying holes is 0.6-1.2 m, a hole isolation skip spraying method is adopted in construction, the operation time interval of the adjacent holes is more than 12 hours, a gas return detection hole is arranged at a wall setting position and is 20-40 cm away from the spraying hole, a gas concentration and pressure sensor is arranged in the hole, the quantity ratio of the spraying holes to the gas return detection hole is 3:1, and spraying parameters are regulated and controlled in real time through detection data.
  8. 8. The spraying type gas extraction plugging method for the gob-side entry retaining wall body is characterized in that an anchoring type high polymer gel material is injected in the step S2 to form a surrounding rock-wall body integrated reinforcing band, spraying is gradually carried out from the periphery to a core area in the step S3, reverse grouting plugging is carried out on a main extraction pipe and an auxiliary extraction pipe in the step S4, a temporary sealing layer is formed by injecting a gas-swelling type high polymer plugging material, and then an inorganic gel type reinforcing material is injected to form a permanent reinforcing layer, wherein the swelling rate of the swelling type high polymer material is 150-250 times, and the 28-day compressive strength of the inorganic gel material is more than or equal to 30MPa.
  9. 9. The spraying type gas extraction plugging method for the gob-side entry retaining wall body according to claim 8, wherein after the gas-swelling type polymer plugging material is injected, when the total gas extraction amount of an extraction network is reduced by more than 70% compared with that before construction and the gas concentration in 4 hours is not obviously increased, the diffusion range of the material is detected, and inorganic gel type reinforcing materials are used for grouting at intervals of 6 to 10 hours, so that the tightness and the structural strength of a plugging layer are ensured.
  10. 10. The method for spraying type gas extraction and blocking along gob-side entry retaining wall body according to claim 1, wherein in step S4, a grouting core pipe is arranged in a main extraction pipe, the extraction pipe continuously extracts gas and reversely grouting is carried out on the gap between the extraction pipe and a hole wall through the core pipe, and a saturation formula is filled according to grouting Controlling grouting quality, wherein For the purpose of filling the grouting with saturation, In order to achieve a practical grouting volume, To draw out the theoretical volume of the gap between the pipe and the hole wall until And filling foaming plugging materials into the diversion trenches in a layered manner and compacting.

Description

Spraying type gas extraction plugging method for gob-side entry retaining wall Technical Field The invention belongs to the technical field of gas extraction plugging, and particularly relates to a spraying type gas extraction plugging method for a gob-side entry retaining wall. Background The gob-side entry retaining is used as a key technology for coal mine efficient mining, can effectively improve the recovery rate of coal resources, reduce the tunneling quantity of the tunnel and reduce the mining cost, and is widely applied to underground coal mine mining. However, the gob-side entry retaining wall body is mainly formed by pouring a roadside filling material, cracks are easily formed at the contact interface of the wall body, the top plate, the bottom plate and the coal wall surrounding rock, the wall body is easy to break and deform under the action of mining pressure, so that gas is easy to permeate and leak through the cracks and pores, and the hidden danger of gas accumulation is formed. At present, the existing gas extraction plugging method mostly adopts a single extraction or single plugging mode, the extraction stage is difficult to accurately position a gas main enrichment area and a seepage channel, the extraction network is unreasonable to arrange, the problems of extraction dead zones, low extraction efficiency and the like exist, the plugging stage mostly adopts integral spraying or simple grouting, special reinforcement is not carried out on easily leaked areas such as edge weak zones and the like, and the plugging material and the construction process are not sufficiently matched, so that a plugging layer is easy to crack and fall off, and the gas leakage phenomenon repeatedly occurs. Meanwhile, the existing technology does not realize the integrated connection of extraction, displacement, plugging and reinforcement, the gas pressure regulation and control in the construction process is inaccurate, safety accidents such as jet holes and gas overrun are easy to cause, and the requirement of long-term safe and stable operation of the gob-side entry retaining cannot be met, so that the development of the accurate, efficient, safe and reliable gob-side entry retaining wall gas extraction plugging method becomes an urgent requirement for solving the current coal mine gas control problem. Disclosure of Invention The invention provides a spraying type gas extraction plugging method for a gob-side entry retaining wall body, which is used for solving the defects in the prior art. The invention provides a spraying type gas extraction plugging method for a gob-side entry retaining wall, which comprises the following steps: S1, carrying out gas seepage and rock mass characteristic detection on a wall to be constructed in an gob-side entry retaining way, positioning a gas main enrichment area and a seepage channel, embedding a main extraction pipe on the surface of the wall, and arranging a dendritic diversion trench along the seepage direction by taking the main extraction pipe as the center and communicating with an auxiliary extraction hole as an auxiliary extraction pipe to form a gas directional extraction network. S2, forming an anchoring spraying hole in an edge weak area where the entry retaining wall body contacts with the surrounding rock, and injecting an anchoring high polymer cementing material to form a surrounding rock-wall body integrated reinforcing band, so that a gas extraction state of an extraction network is maintained in construction. S3, adopting a layered spraying process between the reinforcing belt and the wall body core area, gradually pushing spraying from the periphery to the core area, and directionally driving the gas to a drainage network for centralized drainage by regulating and controlling the spraying pressure and the material diffusion parameters. And S4, after the sprayed layer reaches the design strength, performing reverse grouting and plugging on the main extraction pipe and the auxiliary extraction pipe, and simultaneously filling the compaction diversion trench with a foaming plugging material to complete gas extraction and integral plugging of the gob-side entry retaining wall. According to the gob-side entry retaining wall spraying type gas extraction plugging method provided by the invention, in the step S1, a mode of combining gas multi-point flow measurement with three-dimensional ground penetrating radar scanning is adopted, and a gas seepage judgment formula is adoptedDetermining a main enrichment zone of gas, whereinIs the gas seepage velocity of the gas,For the gas emission quantity of the measuring point,In order to detect the effective area of the cross section,The method is effective porosity of the wall rock mass. And positioning a gas main seepage channel by combining an inversion algorithm, and arranging a main extraction pipe at the position. According to the spraying type gas extraction plugging method for the gob-side entry retaining wall,