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CN-121976819-A - Tunnel pilot tunnel structure for coal seam gas extraction and construction method

CN121976819ACN 121976819 ACN121976819 ACN 121976819ACN-121976819-A

Abstract

The invention relates to a tunnel pilot tunnel structure for coal seam gas extraction, which comprises a small pilot tunnel body formed at the lower end of a main tunnel, wherein a working chamber is formed at the end part of the small pilot tunnel body, a pilot tunnel door safety mechanism is arranged between the working chamber and the small pilot tunnel body, the pilot tunnel door safety mechanism comprises a door frame body, a door body, an air bag plugging device and an inflating device, the inflating device is used for synchronously inflating the air bag plugging device and the working chamber, and the tunnel pilot tunnel structure for coal seam gas extraction can be used for independently excavating a main tunnel working face while tunneling detection and gas extraction are carried out in the small pilot tunnel through the small pilot tunnel structure excavated below the main tunnel, and the two pilot tunnel door safety mechanisms are arranged between the small pilot tunnel and the working chamber in a parallel manner in time space.

Inventors

  • XIA BINWEI
  • XU YIBO
  • ZHANG CHENGPENG
  • TANG JIREN
  • LIU HONGJIE
  • ZHANG YONGKUN
  • ZHANG XINGGUO
  • WANG LEI

Assignees

  • 重庆大学

Dates

Publication Date
20260505
Application Date
20260309

Claims (10)

  1. 1. A tunnel pilot tunnel structure for coal seam gas extraction is characterized by comprising a small pilot tunnel body (7) formed on the end face of a main tunnel, a working chamber (2) matched with a coal seam (9) for gas extraction is formed at the end part of the small pilot tunnel body (7), a pilot tunnel door safety mechanism is arranged between the working chamber (2) and the small pilot tunnel body (7), and comprises a door frame body (12), a door body (11) matched with the door frame body (12), an air bag plugging device arranged on the door frame body (12) and an air charging device matched with the door frame body (12), and the air charging device is used for synchronously charging air bag plugging devices and the working chamber (2).
  2. 2. The tunnel guide hole structure for coal seam gas extraction according to claim 1, wherein the air bag plugging device comprises a section steel support (17) fixedly mounted on a door frame body (12), a supporting seat (21) mounted in cooperation with the section steel support (17) and an inflatable air bag (19) mounted on the supporting seat (21), and the inflatable air bag (19) is inflated and plugged between the door body (12) and the door frame body (12).
  3. 3. The tunnel pilot tunnel structure for coal seam gas extraction as claimed in claim 2, wherein the section of the section steel support (17) is in an isosceles trapezoid shape, a plurality of section steel supports (17) are sequentially connected to form an arch structure matched with the installation of the door frame body (12), and arc-shaped bosses (20) are formed on the inner surface of the section steel support (17) in a protruding mode.
  4. 4. The tunnel guide hole structure for coal seam gas extraction according to claim 2, wherein the door frame body (12) is provided with a guide bracket (22), and the inflatable air bag (19) is arranged between the door frame body (12) and the guide bracket (22).
  5. 5. The tunnel guide hole structure for coal seam gas extraction as claimed in claim 4, wherein an opening groove (23) matched with the inflatable air bag (19) is formed in the middle of the guide bracket (22), and a horn-shaped opening (26) matched with the inflatable air bag (19) is formed in the guide bracket (22).
  6. 6. The tunnel guide hole structure for coal seam gas extraction as claimed in claim 5, wherein the open slot (23) is provided with an open slot inlet end and an open slot outlet end, a limit lug (24) is formed at the open slot outlet end in a protruding mode, and the limit lug (24) is in smooth transition connection with the trumpet-shaped opening (26) and is provided with an arc-shaped groove (25).
  7. 7. The tunnel guide hole structure for coal seam gas extraction according to claim 2, wherein the air charging device comprises an air inlet main pipe (13) fixedly mounted with a section steel support (17), an air guide branch pipe (18) connected with the air inlet main pipe (13), a chamber air inlet (14) mounted on a door frame body (12) and an air inlet mechanism, the air guide branch pipe (18) is connected with an air charging air bag (19), and the air inlet mechanism is used for respectively and synchronously charging the air guide branch pipe (18) and the chamber air inlet (14) through the air inlet main pipe (13).
  8. 8. The tunnel guide hole structure for coal seam gas extraction as claimed in claim 7, wherein the chamber air inlet (14) is arranged at the lower end part of the door frame body (12), and the upper end part of the door frame body (12) is provided with a chamber air outlet (16).
  9. 9. The tunnel pilot tunnel structure for coal seam gas extraction according to claim 1, wherein an upper step (4), a middle step (5) and a lower step (6) are formed on the end face of the main tunnel, the small pilot tunnel body (7) is arranged on the lower step (6), and a safety shed frame (1) is arranged at the small pilot tunnel body (7).
  10. 10. The tunnel pilot tunnel construction method for coal seam gas extraction is characterized by adopting the tunnel pilot tunnel structure for coal seam gas extraction according to any one of claims 1 to 9, and further comprising the following construction steps: s1, performing advanced detection on the top position of a tunnel, and determining the position of a coal seam section; S2, constructing a safety shed frame (1) by adopting a profile steel arch frame at the middle position of the end face of the lower step (6), and excavating a small pilot tunnel at the middle position of the end face of the lower step (6); And S3, excavating a working chamber (2) at the tail end of the small pilot tunnel after the small pilot tunnel is excavated to a designated depth, and installing a pilot tunnel door safety mechanism at the working chamber (2).

Description

Tunnel pilot tunnel structure for coal seam gas extraction and construction method Technical Field The invention relates to the field of tunnel engineering, in particular to a tunnel pilot tunnel structure for coal seam gas extraction and a construction method. Background The coal uncovering (simply called as uncovering) of the tunnel passing through the coal seam is one of the key procedures with the highest risk and the greatest technical difficulty in the tunnel and the underground engineering. Because the coal seam generally contains gas (methane), and the coal seam is low in strength and poor in air permeability, the situation that coal and gas are protruded (dynamic phenomenon) or gas burns and explodes easily occurs at the moment of uncovering the coal seam. In the prior coal uncovering technology of a tunnel crossing a coal seam, the main flow scheme is a parallel pilot tunnel advanced coal uncovering method, the parallel pilot tunnel advanced coal uncovering method has the functions of facilitating drainage, reversing, providing rescue channels and construction, preventing tunnel collapse and the like, but has high manufacturing cost and low efficiency, and meanwhile, the scheme mainly uses geological detection, gas extraction and surrounding rock support as cores, but does not design a special safety isolation system aiming at sudden disasters such as coal and gas outburst, and when the gas outburst is easy to generate, the inside cannot be effectively sealed in time, and the gas is reasonably discharged, so that the safety risk is easy to generate. Therefore, in order to solve the above problems, a tunnel pilot tunnel structure for coal seam gas extraction is needed. Disclosure of Invention According to the tunnel pilot tunnel structure for coal seam gas extraction, the small pilot tunnel structure excavated below the main tunnel is used for tunneling detection and gas extraction in the small pilot tunnel, and meanwhile, the main tunnel working face can be excavated independently, and the two tunnel working faces are parallel in time space and have no mutual interference, so that the construction efficiency is improved, and when the condition of gas protrusion occurs in a coal seam, the pilot tunnel door safety mechanism arranged between the small pilot tunnel and the working chamber can effectively isolate the inside of the tunnel, and meanwhile, the gas can be diluted and extracted, so that the internal safety is ensured. The technical scheme for solving the technical problems is as follows: according to the tunnel pilot tunnel structure for coal seam gas extraction, the tunnel pilot tunnel structure comprises the small pilot tunnel body formed at the lower end of the main tunnel, a working chamber is formed at the end of the small pilot tunnel body, a pilot tunnel door safety mechanism is arranged between the working chamber and the small pilot tunnel body, the pilot tunnel door safety mechanism comprises a door frame body, a door body matched with the door frame body to be installed, an air bag plugging device arranged on the door frame body and an air charging device matched with the door frame body to be arranged, and the air charging device is used for synchronously charging air bag plugging devices and the working chamber. Further, the airbag plugging device comprises a section steel bracket fixedly arranged on the door frame body, a supporting seat matched with the section steel bracket, and an inflatable airbag arranged on the supporting seat, wherein the inflatable airbag is inflated and plugged between the door body and the door frame body. Further, the section of the section steel support is integrally in an isosceles trapezoid shape, a plurality of section steel supports are sequentially connected to form an arch structure matched with the door frame body for installation, and arc-shaped bosses are formed on the inner surface of the section steel support in a protruding mode. Further, a guide bracket is arranged on the door frame body, and the inflatable airbag is arranged between the door frame body and the guide bracket. Further, an opening groove matched with the inflatable air bag is formed in the middle of the guide support, and a horn-shaped opening matched with the inflatable air bag is formed in the guide support. Further, the open slot is provided with an open slot inlet end and an open slot outlet end, a limit lug is formed at the position of the open slot outlet end in a protruding mode, and the limit lug is connected with the horn-shaped opening in a smooth transition mode and is provided with an arc-shaped groove. Further, the air charging device comprises an air inlet main pipe, an air guide branch pipe, a chamber air inlet and an air inlet mechanism, wherein the air inlet main pipe is fixedly installed by matching with the profile steel support, the air guide branch pipe is connected with the air inlet main pipe, the chamber air inlet is installed on the door frame bo