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CN-117145486-B - Drilling directional grouting method

CN117145486BCN 117145486 BCN117145486 BCN 117145486BCN-117145486-B

Abstract

The invention discloses a drilling directional grouting method, a small-section tunnel advanced grouting excavation method and a small-section tunnel advanced support structure, relates to the field of tunnel engineering, and solves the problem that the existing directional grouting scheme cannot effectively control the slurry diffusion direction. The technical scheme includes that after drilling construction is completed, a supporting plate is inserted into a drilling hole, the supporting plate divides the drilling hole into a first grouting area and a second grouting area, mortar is poured into the first grouting area, holes and gaps of a rock-soil body on a control grouting side are sealed, finally a small guide pipe is inserted into the second grouting area of the drilling hole, and grouting is performed, and most of slurry can only diffuse into the rock-soil body on the control grouting side due to the fact that the gaps of the rock-soil body on the control grouting side are sealed, so that directional grouting is achieved. The advanced grouting excavation method for the small-section tunnel adopts the directional grouting method for drilling. The invention is used for directional grouting of the drilled holes and advanced grouting excavation of the small-section tunnel.

Inventors

  • LI ZHENG
  • WANG JINCHUN
  • ZHANG ZHENGDAO

Assignees

  • 中国电建集团成都勘测设计研究院有限公司

Dates

Publication Date
20260508
Application Date
20230809

Claims (10)

  1. 1. The directional grouting method for drilling is characterized by comprising the following steps of: S1, after construction of a drilling hole (1), inserting a supporting plate (2) into the drilling hole (1), wherein the front end of the supporting plate (2) is inserted into the bottom of the drilling hole (1) or a position deeper than the bottom of the drilling hole, two sides of the drilling hole (1) are respectively a control grouting side and a directional grouting side, one side surface of the cross section of the supporting plate (2) is a single-groove M-shaped, the other side surface of the cross section of the supporting plate is a double-groove, the supporting plate (2) divides the drilling hole (1) into a first grouting area (3) positioned on the control grouting side and a second grouting area (4) positioned on the directional grouting side, the first grouting area (3) is one side corresponding to the double grooves of the supporting plate (2), and the second grouting area (4) is one side corresponding to the single grooves of the supporting plate (2); S2, preparing mortar, pouring the mortar into a first grouting area (3) of the drilling hole (1) through a grouting pipe, and closing an orifice of the first grouting area (3) after the mortar is poured; s3, inserting a small guide pipe (5) into a second grouting area (4) of the drill hole (1), preparing slurry and grouting through the small guide pipe (5), wherein grouting holes are formed in the pipe wall of the front section of the small guide pipe (5), and a slurry stopping section is arranged in the rear section of the small guide pipe (5).
  2. 2. The directional grouting method of drill holes according to claim 1, wherein in S1, the front end of the supporting plate (2) is provided with a triangular tip, and the front end of the supporting plate (2) is inserted into the rock soil at the bottom of the drill holes (1).
  3. 3. The method for directional grouting of a borehole according to claim 1, wherein in S2, an accelerator is added during the preparation of the mortar.
  4. 4. The directional grouting method of claim 1, wherein in S3, the front end of the small guide pipe (5) is in a sharp cone shape, the small guide pipe (5) is made of hot rolled seamless steel pipes with wall thickness of 3.5mm and outer diameter of 42mm, the aperture phi of the grouting holes is 8mm, the hole spacing of the grouting holes is 20cm and is arranged in a plum blossom shape, and the length of the grouting stopping section of the small guide pipe (5) is not less than 30cm.
  5. 5. The directional grouting method of a drill hole according to any one of claims 1 to 4, wherein in S3, the small guide pipe (5) is located in a groove on the side face of a single groove of the supporting plate (2), and the rear end of the small guide pipe (5) is fixed in a rock soil body at the hole opening of the drill hole (1) through an anchoring piece.
  6. 6. The directional grouting method for drill holes according to any one of claims 1 to 4, wherein in S3, stiffening hoops are arranged at the rear ends of the small guide pipes (5), and the width of the supporting plate (2) is larger than or equal to the diameter of the drill holes (1).
  7. 7. The method for directional grouting of a borehole according to any one of claims 1 to 4, wherein S3, after the small pipe (5) is inserted, the second grouting area (4) is cleaned and grouting is performed.
  8. 8. The advanced grouting excavation method for the small-section tunnel is characterized by comprising the following steps of: A. drawing an excavation outline on the tunnel face, marking drilling holes and drilling holes outside the arching line and along the arching line direction respectively, wherein the drilling direction is inclined upwards; B. Step S1 of the method for directional grouting of boreholes according to any of the preceding claims 1 to 7, respectively inserting a pallet (2) in each borehole (1), the plane corresponding to the pallet (2) being perpendicular to the radial direction of the arching line, The first grouting area (3) is positioned close to one side of the tunnel to be excavated, and the second grouting area (4) is positioned back to one side of the tunnel to be excavated; C. the method for directional grouting of boreholes according to any one of the preceding claims 1 to 7, comprising the step S2 of injecting mortar into the first grouting areas (3) of the respective boreholes (1), respectively; D. the method for directional grouting of drill holes according to any one of claims 1 to 7, wherein in step S3, small guide pipes (5) are respectively inserted into the second grouting areas (4) of the drill holes (1) and respectively grouting is performed, so that an arch-shaped solidified shell is formed; E. and excavating, deslagging and supporting the tunnel.
  9. 9. The method for advanced grouting excavation of small-section tunnels according to claim 8, wherein in the step A, the distance between adjacent boreholes (1) is 30-40 cm, and the elevation angle of each borehole (1) is not more than 5 degrees.
  10. 10. The advanced grouting excavation method of the small-section tunnel according to claim 8 or 9, wherein in the step D, after the small guide pipes (5) are inserted into the second grouting area (4) of the drill hole (1), the rear ends of the small guide pipes (5) are connected into a whole through connecting ribs, and the connecting ribs are fixed on a rock-soil body by soil nails and grouting is carried out respectively.

Description

Drilling directional grouting method Technical Field The invention relates to the field of tunnel engineering, in particular to a drilling directional grouting method, a small-section tunnel advanced grouting excavation method and a small-section tunnel advanced support structure. Background At present, the excavation construction of a small-section tunnel at a hole section which is broken in a weak state and has underground water mainly adopts an advanced small-conduit grouting method, rock and soil bodies after advanced drainage are pre-consolidated through advanced small-conduit grouting, an arch-shaped shell is formed above an excavation section, and the capability of resisting the top load of the tunnel is enhanced. The conventional advance small conduit grouting method has the defects that when the small conduit grouting method is used for grouting the small conduit, the slurry is easier to enter the rock-soil body in the excavation range downwards in the weak broken hole section with underground water, so that the rock-soil body in the excavation range is solidified and hardened, and the actual grouting amount of the rock-soil body outside the excavation range is insufficient, thereby not only causing slurry waste, but also increasing the excavation difficulty and construction risk. In addition, the diameter of the drilling hole of the small guide pipe is matched with the outer diameter of the grouting pipe, and is generally not more than 50mm, so that the number of the drilling holes is large, and the construction speed is slow. In order to save the cost, the drilling intervals of the small guide pipes are generally controlled to be 20-50 cm, the intervals of the small guide pipes are larger, the rock and soil bodies in the middle parts of two adjacent small guide pipes are difficult to solidify and harden effectively, loose rock and soil bodies fall off, and potential safety hazards and even collapse risks exist. The patent with publication number CN 112538850A discloses a device and a method suitable for advanced grouting of a pipe gallery for tree protection, and solves the problem of tree protection in construction of an underground comprehensive pipe gallery through directional grouting. The device comprises a directional grouting pipe, wherein the directional grouting pipe is provided with a grouting directional plate for limiting grouting liquid in the grouting pipe from a grouting hole to structural diffusion on one side of the grouting pipe, the grouting directional plate is positioned on the longitudinal outer wall on one side of the grouting pipe, the grouting pipe on the inner side of the grouting directional plate is provided with a grouting hole, the width of the grouting directional plate is larger than or equal to the diameter of the grouting pipe, and the length of the grouting directional plate is larger than or equal to the design length for limiting grouting liquid in the grouting pipe from the grouting hole to structural diffusion on one side of the grouting pipe. The directional grouting pipe blocks the diffusion direction of grouting liquid through the grouting directional plate, and because a gap exists inevitably between the wall of a drilled hole and the grouting directional plate and a gap exists inevitably in a rock-soil body of the wall of the drilled hole, grouting is completed once, the grouting directional plate has weak blocking effect on grouting liquid diffusion, and grouting liquid can not be blocked from diffusing upwards under the condition of sufficiently low grouting pressure, and grouting liquid cannot be blocked from diffusing downwards. Disclosure of Invention The invention firstly provides a drilling directional grouting method, which solves the problem that the existing directional grouting scheme can not effectively control the slurry diffusion direction. The technical scheme adopted by the invention is that the directional grouting method for drilling comprises the following steps: S1, after drilling construction is completed, inserting a support plate into a drilling hole, wherein the front end of the support plate is inserted into the bottom of the drilling hole or a position deeper than the bottom of the drilling hole, two sides of the drilling hole are respectively a control grouting side and a directional grouting side, the cross section of the support plate is in an M shape, one side surface of the support plate is a single groove, the other side surface of the support plate is a double groove, the support plate divides the drilling hole into a first grouting area positioned on the control grouting side and a second grouting area positioned on the directional grouting side, the first grouting area is one side corresponding to the double groove of the support plate, and the second grouting area is one side corresponding to the single groove of the support plate. In order to facilitate the insertion of the supporting plate into the drilled hole, the