Method for enlarging and digging tunnel portal at weak surrounding rock section in tunnel

Abstract

The invention relates to a method for enlarged excavation of a pipe-shed workroom on a soft surrounding rock land section which has become a primary support in a tunnel, which belongs to the technical field of a tunnel construction method. The method comprises the following basic steps: a working land section is selected; the working land section is reinforced; and after reinforcement, the working land section undergoes enlarged excavation and novel support is performed during the process of enlarged excavation. The basic steps are monitored and safety devices are arranged in the basic steps; the basic step of reinforcement contains drilling of a grout pipe along an arched torus of the tunnel, and grouting into the grout pipe; the basic step of enlarged excavation and novel support contains removal of the primary support of the working land section at intervals, enlarged excavation from the arched torus to a novel arched torus, cutting of the exposed grout pipe after enlarged excavation, and implementation of novel support on the novel arched torus; and the steps are repeated, so as to complete the steps of removal of the primary support, enlarged excavation, cutting of the grout pipe and implementation of novel support of the residual working land section. The method can be directly used for enlarged excavation of the pipe-shed workroom on the soft surrounding rock land section which has become the primary support in the tunnel, thereby being favorable for construction of a pipe shed and reducing the construction cost of the pipe shed.

Description

technical field [0001] The invention relates to a method for expanding and excavating a section of a tunnel with primary branches, in particular to a method for expanding and excavating a pipe shed studio in a section of soft surrounding rock with primary branches in a tunnel, which belongs to the tunnel construction method technology field. Background technique [0002] The pipe shed construction method is currently the commonly used advanced support technology for the excavation of shallow buried tunnels. Because the pipe shed construction equipment occupies a large area and requires a large working environment, the pipe shed construction is generally used for the initial excavation of the tunnel opening. The weak surrounding rock of the section is supported in advance. For the construction of the pipe shed in the weak surrounding rock section of the tunnel, usually the exact location of the weak surrounding rock section in the tunnel is first determined according to the ...

AI Technical Summary

Problems solved by technology

In this way, the distance between the expanded pipe shed studio and the weak surrounding rock geological area is long, and the length of the pipe shed is very long, which makes the construction of the pipe shed complicated and inconvenient and the cost is too high. Sometimes the distance is too long to be carried out. Pipe Shed Construction

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