A construction method for removing the enclosure structure of the end portal of the shield section

Abstract

The invention discloses a construction method for breaking an end socket tunnel portal retaining structure of a shield section. The method comprises the following steps of 1, drilling holes in a circular tunnel portal of the retaining structure; 2, stirring expansion slurry; 3, injecting the stirred expansion slurry into vertical holes and longitudinal holes, sealing the holes, and pre-cracking concrete; 4, chiseling a launching surface of the circular tunnel portal; 5, dividing the circular tunnel portal into a first area, a second area, ... and an nth area; 6, sequentially carrying out concrete peeling and reinforced concrete breaking on the launching surface of the circular tunnel portal in the first area, the second area, ... and the nth area; 7, chiseling a soil surface of the circular tunnel portal; 8, carrying out shield launching / reception tunneling construction. According to the method, through reasonable drilling arrangement and precise drilling depth, it is ensured that theconcrete breaking range of the tunnel portal can meet clearance requirements of design and construction; the whole process has high safety, collapse does not easily occur, the construction is fast, and meanwhile, the safety of construction personnel is ensured.

Description

technical field [0001] The invention belongs to the technical field of shield tunneling / excavation reception construction, and in particular relates to a construction method for removing the enclosure structure of a portal at the end of a shield tunneling section. Background technique [0002] The shield section of the urban rail project often uses the station as the starting and receiving working well. Before the shield tunnel starts or receives, the station enclosure structure within the tunnel door must be broken to ensure that the steel bars in the enclosure structure are not aligned with the shield cutter head. make an impact. The soil at the end of the shield section is generally reinforced by the ground reinforcement method, but the retaining structure of the end soil layer is weakened after the opening of the portal is broken, and there is a possibility of water and sand gushing at the portal, and even the possibility of the soil at the end collapsing. The originati...

AI Technical Summary

Problems solved by technology

Conventional portal demolition methods have low work efficiency and long construction period. After the foundation pit enclosure structure at the portal is weakened, the time from the top of the shield cutterhead to the soil on the face of the tunnel is too long, and risky times are often prone to occur during this period, such as water gushing Sand gushing, mud dropping, etc., if not properly handled, will lead to soil collapse

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