Large-arch-foot three-step tunnel rapid construction method and structure based on pipe shed pre-supports

Abstract

The invention discloses a large-arch-foot three-step tunnel rapid construction method and structure based on pipe shed pre-supports. Short pipe sheds are constructed through a hole interior non-work-room pipe shed construction technology to reinforce and support surrounding rock in front of a tunnel face in advance; large arch feet are arranged at bases all stages of steps; and under dual controlmeasures, the tunnel cross section is sequentially excavated by three steps, according to the specific processes, firstly, short pipe shed advance supports are constructed within a certain range alongan arch part of a tunnel, the upper, middle and lower steps are sequentially excavated with alternate distances, after excavation of each step, the primary supports are constructed instantly, footings of the primary supports are designed to of a large-arch-foot type, and when the lower step is away from a secondary lining of a former cycle by the tunnel diameter, an inverted arch, side walls, a filled layer and a secondary lining are constructed. The problem that under the condition of the shallow-buried weak surrounding rock, deformation control over the tunnel is difficult is solved, and meanwhile the disadvantages that under the same condition, a traditional construction method is many in subsection, numerous in working procedure, slow in construction, many in temporary support and thelike are further overcome.

Description

technical field [0001] The invention relates to the field of tunnel construction, in particular to a rapid construction method and structure of a three-step tunnel with a large arch foot based on pipe shed pre-support. Background technique [0002] In recent years, with the vigorous development of my country's infrastructure construction, more and more tunnel projects have appeared. In some shallow tunnels passing through weak surrounding rock, large deformation problems such as primary support deformation and cracking, limit invasion and even landslide and roof fall are common occurrences, which seriously affect the safety and progress of tunnel construction, thereby increasing the project cost. [0003] In view of the above situation, in order to prevent the occurrence of large deformation disasters and ensure construction safety, most of the methods at home and abroad are currently using various divisional excavation methods with complicated procedures, among which the CR...

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Problems solved by technology

[0005] The technical problem to be solved by the present invention is to provide a tunnel construction method and structure that can not only control the deformation of the tunnel, ensure construction safety, but also speed up the construction progress and reduce the construction cost in view of the deficiencies of the above construction methods.

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