Under-pressure chamber opening method for shield tunneling machine in coarse-grain soil stratum

Abstract

The invention discloses an under-pressure chamber opening method for a shield tunneling machine in a coarse-grain soil stratum. The under-pressure chamber opening method comprises the steps of preparing thin mud, and making the thin mud permeate into the stratum to form a stable permeation band to reduce permeability of the stratum; replacing the thin mud with thick and high-density mud to form a tight mud type of mud membrane on the surface of the stratum to reduce breathability of the stratum; setting a pressure value of under-pressure chamber opening by testing a airtightness value of the mud membrane through an indoor test and airtightness effect through an in situ test; reducing the liquid level of mud of a pressure chamber to the position below a maintenance surface, and performing under-pressure chamber opening under protection of local pressure by means of the airtightness of the mud membrane; repairing the mud membrane on an excavation face by ascending and descending the liquid level of the mud of the pressure chamber during chamber opening. By means of the under-pressure chamber opening method for the shield tunneling machine, under-pressure chamber opening of the shield tunneling machine is achieved safely and quickly in the coarse-grain soil stratum with high water pressure and strong permeability. Furthermore, the under-pressure chamber opening method for the shield tunneling machine is simple in operation, economical and suitable for current national conditions in China.

Description

technical field [0001] The invention belongs to the technical field of underground engineering construction, and specifically relates to a method for opening a cabin under pressure of a shield machine in a coarse-grained soil layer. Background technique [0002] Due to the complex and changeable geological conditions in our country, there are often situations such as serious wear of the cutter head of the shield machine, cake formation on the cutter head, obstacles in front of the cutter head, mismatch between the cutter and the stratum, etc., and it is necessary to stop the machine for cleaning or maintenance. and other operations, resulting in low efficiency of shield tunneling. At present, frequent downtime and opening of cabins has become an obvious feature of my country's shield technology, and it also greatly restricts the development of my country's shield technology. With the construction of many large-scale underwater tunnels in my country, especially when crossi...

AI Technical Summary

Problems solved by technology

Existing for strong water permeability (permeability coefficient greater than 10 -2 cm / s) in the coarse-grained soil layer of the shield machine, there are some auxiliary processes that take a long time and require a large amount of engineering. There are problems of high difficulty, time-consuming and high engineering cost in press-opening the cabin

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