Construction method of open-arch concealed half-wall and half-arch protection structure of shallow-buried bias tunnel penetrating through accumulation body

Abstract

The invention discloses a construction method of an open-arch concealed half-wall and half-arch protection structure of a shallow-buried bias tunnel penetrating through an accumulation body. The construction method comprises a half-wall and half-arch protection structure body and an open-arch concealed reverse underground excavation tunnel-entering construction method. The open-arch concealed reverse underground excavation tunnel-entering construction method comprises the steps of backpressure backfill, advanced grouting supporting, a three-step seven-step reserved core geotechnical method anda monitoring and measuring method. According to the construction method, backfill soil is used for carrying out foot protection backpressure on the accumulation body, then a large pipe shed and a reinforcing mesh are constructed on the accumulation body, concrete is backfilled, and arch ring effect protection is formed; the supporting surfaces on the two sides of a semi-exposed and semi-concealedsleeve arch provide a protection body for underground excavation, and the accumulation body is less disturbed to maintain a relative stable state; and the tunnel portal protection structure is stablein type, simple in structure and good in stress performance, under the protection effect of the half-wall and half-arch sleeve arch, the safety, reliability and economical efficiency of tunnel construction are greatly improved through the construction method of reverse underground excavation out of a tunnel, large excavation is avoided, and the ecological environment is protected.

Description

technical field

[0001] The invention belongs to the technical field of tunnel engineering construction such as highway engineering and railway engineering, and relates to the construction of tunnels passing through unfavorable geological sections, in particular to the entry construction of entrance engineering in unfavorable geological sections, and in particular to an open and concealed construction of shallow-buried bias-pressure tunnels passing through accumulative bodies The construction method of half-wall half-arch protective structure. Background technique

[0002] The construction of the tunnel entrance through the accumulation body has always been a technical difficulty and the focus of safety control in tunnel construction. The use of traditional direct open-cutting into the hole will inevitably cause disturbance of the accumulation body and cause landslides and mountain deformation. The accumulation body needs to be cleaned in advance. Pile pre-reinforcement grout...

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