Metro shield tunnel extension steel ring initial construction method

Abstract

The invention discloses a metro shield tunnel extension steel ring initial construction method. The method comprises the following steps that 1, initiating end stratum effect inspection is conducted,nine tunnel portal manholes are made in the range of a solid in the tunnel portal ring before formal construction of shield launching, wherein the depth of the tunnel portal manholes is half of the longitudinal length of end reinforcement, and the water seepage situation is observed; 2, a tunnel portal extension ring is installed, wherein one end of the tunnel portal extension ring is connected with a tunnel portal steel ring through an M20 bolt. The method has the advantages that the extension steel ring replaces the method that even wall is chiseled away manually to obtain a cutter rotationspace, the phenomenon that construction environment pollution is caused in the process of chiseling away the even wall is avoided, and meanwhile the phenomena that after the wall is chiseled, the tunnel face is unstable, and collapsing occurs are eradicated; compared with the method of manually chiseling away the even wall, extension steel ring installation is easy and rapid, and the shield launching construction period is shortened; gushing, air leakage, earth subsidence and the like occurring at the time of shield launching are effectively controlled, and the influence on surroundings is small.

Description

technical field [0001] The invention relates to the technical field of excavation and excavation construction of a subway shield tunnel, in particular to a construction method for the initiation of an extended steel ring of a subway shield tunnel. Background technique [0002] At present, subway construction in major cities across the country is being carried out on a large scale. Shield construction is the protagonist of subway construction, and the initial entry of shield tunnels is a major source of risk during shield construction. In previous constructions, due to the short distance between the door seal and the face of the tunnel, in order to ensure that the cutter head of the shield machine will not damage the cord rubber sheet when the ground connection wall is broken, the cutter head should be removed Before the ground connection wall, the ground connection wall is usually chiseled to a depth of 60cm by manual operation to ensure the space for the cutter head to rota...

AI Technical Summary

Problems solved by technology

According to past construction experience, manual chiseling of the ground connection wall is a time-consuming and risky work. During the chisel removal process, a large amount of dust pollution will be generated, which will affect the construction environment of the workers. After 60cm of chiseling (the thickness of the ground connection wall is 80cm) It is easy to cause face instability and increase the risk of starting the shield machine, thus seriously delaying the progress of the starting of the shield machine

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