Construction method of large-span asymmetrical double-arch railway tunnel under terrain bias pressure condition

Abstract

The invention provides a construction method of a large-span asymmetrical double-arch railway tunnel under a terrain bias pressure condition. The method is used for greatly shortening construction period and improving construction efficiency by simplifying construction steps. In the construction method, a middle pilot tunnel, an inside tunnel chamber and an outside tunnel chamber are sequentiallyexcavated, and unbalanced support systems are adopted in the inside tunnel chamber and the outside tunnel chamber, which effectively controls deformation of the top part of a middle partition wall and arch parts of the big main tunnel chamber and the small main tunnel chamber as well as side walls (the maximum deformation is controlled within 20mm), greatly shortens construction period, simplifies construction steps, improves construction efficiency by 30%, and the problem of water leakage on the top part of the middle partition wall is effectively solved.

Description

technical field [0001] The invention relates to a construction method for a railway tunnel, in particular to a construction method for constructing a large-span asymmetric double-arch railway tunnel under the condition of terrain bias. Background technique [0002] Double-arch tunnels have been practiced in my country for more than 30 years, and most of them are used in road tunnels. Interlaced with each other, the surrounding rock stress change and lining load conversion are very complicated, especially the middle wall is stressed, including compression, tension, bending, torsion and shearing. In addition, the stress distribution of the surrounding rock and the stress and deformation of the lining during the construction process are not clear. Crack or even collapse. [0003] At present, my country's multi-arch tunnel mainly adopts the construction method of three pilot tunnels, that is, the central pilot tunnel goes first, and the bilateral pilot tunnels follow up. The p...

AI Technical Summary

Problems solved by technology

However, the construction method of three pilot tunnels has complicated construction procedures, and when the surrounding rock level is good, it directly affects the construction period and cost of the multi-arch tunnel.

[0004] Among them, after more than 30 years of road tunnel construction and scientific research, my country is still relatively weak in the construction of multi-arch tunnels. The main problems are reflected in the single construction method and complicated construction procedures, as many as 22 steps; the overall support system is generally too strong, But the local location is relatively weak; there are many diseases in the built tunnels, such as large-area cracks in the lining, water seepage and water leakage; the project cost is too high for the shallow buried section of the entrance and exit and the section with poor surrounding rock; the large-span asymmetric double-arch The engineering practice of railway tunnels is almost blank in China

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