Rapid supporting device for reducing early settlement of shallow-buried excavation tunnel and construction method

Abstract

The invention discloses a rapid supporting device for reducing early settlement of a shallow-buried excavation tunnel and a construction method. The rapid supporting device for reducing early settlement of the shallow-buried excavation tunnel comprises an arch frame, and a plurality of air cushions are arranged at the top of the arch frame at intervals. The construction method comprises the following steps that (a), a contour line is measured after tunnel excavation, and overexcavation data and position are calculated; (b), the arch frame is erected, the air cushions which are not inflated are arranged at the top of the arch frame; (c), after the arch frame is erected, air inflation is carried out on the air cushions, and the surrounding rock is supported by the air cushions; (d), guniting is carried out, concrete is sprayed to the arch frame to enable the concrete to fill the space outside the air cushions; (e), the air cushions are taken out; and (f), grout supplementing is carried out, and the original positions of the air cushions are filled with the concrete. Therefore, the plurality of air cushions are arranged at the top of the arch frame, transitional support is provided for the surrounding rock by utilizing the air cushions, initial settlement of the surrounding rock is restrained, and initial deformation and stability of the surrounding rock are effectively controlled before a guniting procedure is completed.

Description

technical field [0001] The invention relates to the technical field of tunnel engineering, in particular to a rapid support device and a construction method for reducing the early settlement of shallow-buried tunnels. Background technique [0002] When constructing a tunnel project, if the initial deformation and stability of the tunnel surrounding rock cannot be effectively controlled, it will have extremely adverse effects on the construction of the tunnel project and its surrounding environment. Construction proceeded in an orderly manner. Especially in downtown areas, underground pipelines, ground buildings, traffic, etc. are very sensitive to settlement. The step method is a commonly used construction method in tunnel construction. When excavating the upper steps in the step method, the excavation and erection of the arch frame (including the installation of mesh pieces, the installation of small ahead conduits, the locking foot anchor pipes, and the longitudinal conne...

AI Technical Summary

Problems solved by technology

[0003] This is a traditional approach. However, in actual construction, after the excavation of the tunnel, it takes a certain amount of time to erect the arch frame and spray the grout, and it is often difficult for the shotcrete to closely adhere to the surrounding rock, so after the excavation and unloading, the surrounding rock continues to Most of the deformation is due to the fact that the system of shotcrete and arch frame is close to the surrounding rock and begins to bear force after several cycles of footage, so the initial settlement of the surrounding rock cannot be contained, resulting in a large amount of settlement of the surrounding rock, and Early settlement is the main part of the entire settlement. After more than 30 years of experience accumulation, it has been confirmed that the total settlement of the underground excavation tunnel is divided into four stages: the first stage 10% (the settlement that was not measured before the buried point), 60% in the second stage (excavation of the vertical arch shotcrete on the upper steps), 20% in the third stage, and 10% in the late stage of the fourth stage. Faster support is used to control the early rapid settlement deformation accounting for 60% of the total settlement It is the new and higher requirements of people for the environment in the new era. The past practice of sinking first and then repairing the ground and related facilities is no longer acceptable.

Moreover, excessive settlement will bring hidden dangers to the stability of the tunnel. When the consequences are serious, it will cause the ground above the tunnel to collapse, damage buildings and pipelines, and cause huge casualties and property losses.

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