A construction method for the support of multi-arch tunnel without chamber and large pipe shed

Abstract

The invention discloses a method for constructing a multiple-arch tunnel hole body large room-free pipe shed support. The construction working procedures comprise composite guide wall construction and guide pipe mounting, drilling, large pipe shed and reinforcement cage mounting, composite type guide wall casting concrete layer breaking and removing, discarded drilled segment soil excavation, grouting, large pipe shed supporting segment excavation, next circular construction and the like. The method avoids multi-cycle repeated expanding excavation of a pipe shed working room in a multiple-arch tunnel, reduces construction risks, the expanding excavation earth volume, the use amount of primary supporting second lining concrete and the number of steel arches and saves engineering cost; the construction speed is improved, and the working efficiency is greatly improved; the construction risks like the possibly-caused tunnel damage caused by stress concentration and the like due to the fact that a cross section is expanded and the pipe shed working room is excavated in the weak poor stratum are reduced, and the influence of urban narrow underground space on near existing constructed (built) buildings is reduced; and compared with a traditional pipe shed advance support with the working room, the whole advance support and tunnel excavation process is safer and more reliable.

Description

technical field [0001] The invention belongs to the technical field of tunnel construction, and in particular relates to a construction method for supporting a multi-arch tunnel body without a large pipe shed. Background technique [0002] In order to control the relaxation of the surrounding rock in a large range, a special reinforcement method is required. This method is to first carry out reinforcement construction in the surrounding rock in front of the tunnel face, and then carry out excavation within its range. This method The construction method is called advance support. [0003] Pipe shed support is an advanced support method when passing through shallow buried, weak and broken rock masses, collapsed sections and other unfavorable geological layers in underground engineering construction. The support of the pipe shed is to drill a hole along the excavation circle line with a certain external angle with the tunnel axis. Then insert steel pipes of different diameter...

AI Technical Summary

Problems solved by technology

[0005] 1. The increased excavation section and repeated changes in the excavation section can easily cause stress concentration and increase the construction risk level, which is not conducive to safe construction

[0006] 2. The amount of excavated earthwork increases, the amount of initial support increases, and the cost of the project increases

[0007] 3. For the multi-cycle continuous large pipe shed construction site, the pipe shed workshop must be excavated in each cycle, which is difficult to construct and affects work efficiency

[0008] 4. When the second lining is constructed after the tunnel excavation is completed, it not only increases the amount of concrete, but also affects the second lining formwork trolley

[0010] 1. The expansion and excavation of the pipe shed studio will occupy the structural space of the middle wall of the multi-arch tunnel. If the thickness of the middle wall structure is kept constant, the line will be widened, resulting in irregular lines, irregular structures, increased construction difficulty, engineering volume and investment. increase etc.

If the line is kept straight and unchanged, the expansion and excavation will encroach on the thickness of the middle wall structure, which will bring about problems such as structural safety, structural irregularities, and increased temporary reinforcement and support works.

[0011] 2. The expansion and excavation of the pipe shed studio will cause the adjacent hole space to be occupied, resulting in complex structural design, difficulty in switching construction steps, and low construction efficiency.

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