A kind of anti-collapse treatment method for tunnel entrance in soft rock

Abstract

The invention discloses a collapse prevention processing method for a soft rock tunnel portal. The collapse prevention processing method includes the following steps that firstly, excavation construction of a tunnel portal section is conducted, wherein excavation construction is conducted on the tunnel portal section from back to front, and preliminary bracing and secondary lining construction are conducted synchronously; secondly, the tunnel portal is lengthened and strengthened, wherein in the excavation construction process of the tunnel portal section, a lengthened cover pillar is used for strengthening the tunnel portal; the lengthened cover pillar comprises a plurality of structural steel arch frames which are erected on the outer side of the tunnel portal of a construction tunnel from back to front, an arch support located on the outer side of the tunnel portal is formed by the structural steel arch frames and is paved with a layer of reinforcing mesh, a concrete layer is ejected on the arch support, and a rigidity strengthening arch for strengthening the outer side of the tunnel portal is composed of the structural steel arch frames, the reinforcing mesh and the concrete layer. The collapse prevention processing method is simple in step, reasonable in design, convenient to construct, good in using effect and capable of effectively preventing the constructed soft rock tunnel portal from collapsing and ensuring the construction safety and the construction period.

Description

technical field [0001] The invention belongs to the technical field of tunnel construction, in particular to an anti-collapse treatment method for soft rock tunnel entrances. Background technique [0002] At present, the construction period of various projects is relatively tight, and the reasonable construction period has been compressed, ranging from a few months to shortening the construction period to half a year or even a year. For extra-long tunnels, without auxiliary pilot pits, the construction is close to the two working faces of the entrance and exit, and the construction period is extremely tight, especially in the case of poor surrounding rock conditions and frequent collapses, the construction progress is difficult. In the actual construction of soft rock tunnels, collapses often occur, especially in the process of tunnel excavation, where the tunnel openings formed by excavation are prone to collapse, which requires corresponding anti-collapse measures. Since ...

AI Technical Summary

Problems solved by technology

Since the construction of soft rock tunnels is based on safety, but due to the guarantee of the construction period, the requirements for construction safety and progress are relatively high. At present, there are few researches on rapid construction technology of soft rock tunnels at home and abroad, and there are very few reference materials.

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