Gate-type roof brushing construction method of extreme weak and broken surrounding rock layer

Abstract

The invention provides a gate-type roof brushing construction method of an extreme weak and broken surrounding rock layer. The gate-type roof brushing construction method of the extreme weak and broken surrounding rock layer comprises the following steps that S(1) a parallel pilot tunnel and a transverse channel are excavated by adopting a three-step method, and the parallel pilot tunnel and transverse channel support is constructed; S(2) a special-shaped gate-type supporting frame attached to a main hole outline is erected at a connecting position of the transverse channel and a main hole; S(3) a trapezoidal pilot tunnel of the main hole is excavated by adopting the three-step method along a hole top arc outline of the main hole in the width direction of the main hole, and temporary support is constructed on the trapezoidal pilot tunnel; S(4) primary support and secondary support are constructed on the trapezoidal pilot tunnel completing the temporary support; S(5) the main hole is excavated by adopting the three-step method separately facing the directions of large mileage and small mileage; and S(6) secondary lining is constructed on the main hole formed by the excavation. The gate-type roof brushing construction method of the extreme weak and broken surrounding rock layer can open up a new working surface, the special-shaped gate-type supporting frame used in the gate-typeroof brushing construction method improves the construction efficiency of a tunnel, and stress at the connecting position of the transverse channel and the main hole is intensified.

Description

technical field [0001] The invention relates to the field of tunnel construction, in particular to a door-type roofing construction method for extremely weak and broken surrounding rock layers. Background technique [0002] With the continuous development of my country's transportation construction, the number of extremely weak and broken surrounding rock tunnels in the project is increasing and the length is increasing. In order to complete the construction tasks within the tight construction period, it is often necessary to open up new working faces. The method of the new working surface is particularly important. In the traditional roof construction, vertical portal steel frames are often used at the junction of cross passages and tunnels, but the distance between the vertical portal steel frames and the trapezoidal scaffolding is relatively long, and the connected steel will be subject to large shear stress from the upper surrounding rock , and produce a large bending mo...

AI Technical Summary

Problems solved by technology

In the traditional roof construction, vertical portal steel frames are often used at the junction of cross passages and tunnels, but the distance between the vertical portal steel frames and the trapezoidal scaffolding is relatively long, and the connected steel will be subject to large shear stress from the upper surrounding rock , and produce a large bending moment; the over-excavation area required for the installation of the connected section steel is large, the work efficiency is low, and the time is long; when the secondary lining is reinforced, the over-excavation is likely to cause the secondary lining to be subjected to a large bias load

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