Tunnel front edge support construction method

Abstract

The invention discloses a tunnel front edge support construction method. An advance support is arranged in a tunnel and comprises a plurality of rows of arch frames and advance small guide pipes arranged corresponding to the arch frames. The front edge support method includes the steps that S1, an area between a tunnel face and the arch parts of the arch frames closest to the tunnel face is a front edge area; S2, when an advance small guide pipe is exposed due to small collapse or chipping in the front edge area, the top area of the advance small guide pipe is covered with a reinforcing mesh, and the reinforcing mesh is fixed to the advance small guide pipe; and S3, concrete is sprayed, specifically, the concrete is gradually sprayed to the bottom of the advanced small guide pipe tightly attached to the inner wall of the top of the tunnel, and the area between the advanced small guide pipe and the inner wall of the top of the tunnel is filled with the sprayed concrete and wraps the advanced small guide pipe and the reinforcing mesh. The tunnel front edge support construction method is particularly suitable for a weak broken surrounding rock tunnel, the span of a longitudinal arch can be effectively reduced, and collapse of the tunnel face is prevented.

Description

technical field [0001] The invention relates to the technical field of tunnel engineering, in particular to a tunnel front support construction method applied to mines with weak and broken surrounding rocks. Background technique [0002] At present, a large number of surrounding rock stability issues are involved in the construction of tunnel projects such as transportation, mining, and water conservancy. The excavation of the tunnel caused the surrounding rock supporting the tunnel body to be excavated, and a void appeared behind the face of the tunnel, and the stress of the surrounding rock was redistributed, causing the surrounding rock to deform toward the tunnel clearance. This deformation includes in-plane vertical, transverse deformation and out-of-plane longitudinal deformation of the palm face. It is especially obvious when the tunnel passes through the weak and broken surrounding rock stratum. The face of the tunnel and the vault collapse, showing that the tunnel ...

AI Technical Summary

Problems solved by technology

[0005] In a word, in the research of the existing technology, generally focus on the optimization analysis of the existing design scheme or the optimization design of the parameter range, however, there are few innovations and developments in the support method itself, and the support construction in the prior art is either It is too complicated and cumbersome, too conservative under certain conditions, resulting in waste, or the construction design is too weak and there is a big safety hazard, which brings a big safety risk to the construction and later operation of the tunnel project, so it cannot be solved perfectly The face of the tunnel and the vault cavity are prone to collapse when the tunnel passes through the weak and broken surrounding rock strata, which needs to be improved urgently

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