Out-of-pit tunneling construction method for minimum spacing tunnel

Abstract

The invention provides an out-of-pit tunneling construction method for a minimum spacing tunnel, and belongs to the technical field of out-of-pit tunneling construction of small spacing tunnels. The out-of-pit tunneling construction method comprises the following steps that a left line upper step section is excavated, and a left line lower step left section and a left line lower step right sectionare excavated separately; a left line inverted arch and a left line filling layer are constructed, and a left line secondary lining is piled in a staggered mode; a right line small guide hole sectionis excavated, a right line upper step right section, a right line upper step left middle section and a right line upper step left edge section are excavated in an expanded mode, and a right line upper step primary support is constructed; a small guide hole primary support is removed, a right line lower step left section and a right line lower step right section are excavated, and a right line lower end face primary support is constructed; and a right line inverted arch and a right line filling layer are constructed, and a right line secondary lining is subjected to overall model-building. According to the out-of-pit tunneling construction method, an advanced tunnel is subjected to one-way out-of-pit tunneling, so that the problem that cliff construction of the exit section is inconvenientis solved; after a left tunnel is excavated, a middle rocky column is reinforced, the left line secondary lining is piled in the staggered mode, a right tunnel adopts an advanced small guide hole forout-of-pit tunneling, the section is excavated in an expanded mode, the construction risk is reduced, and tunnel construction safety is ensured.

Description

technical field [0001] The invention relates to the technical field of tunnel exit construction with a small clear distance, in particular to a construction method for an exit tunnel with a very small clear distance. Background technique [0002] In the prior art, due to considerations of route planning requirements and terrain constraints, it is sometimes unavoidable to adopt tunnels with a small clear distance for traffic routes. The traditional small distance tunnel has the problem of mutual influence between structural safety and construction, and measures must be taken to solve it. [0003] The old house-based tunnel of the Xingyi Ring Expressway in Guizhou Province has a total length of about 393m and is a bifurcated short tunnel. The distance between the tunnel lines at the exit section is 0.6m from the minimum contour line, and then gradually divided into very small net distance, small net distance, and separate tunnels, and the line distance at the entrance section...

AI Technical Summary

Problems solved by technology

[0008] The purpose of the present invention is to provide a tunnel exit construction method with a very small clear distance, so as to solve the technical problems of many construction procedures, complicated structural stress, long construction period and high cost

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