Single-hole double-layer overlapping tunnel structure and construction method thereof

Abstract

The invention provides a single hole double layer overlapping tunnel structure including the single hole tunnel which the high side wall with the high / stride ratio is bigger than 2, the composite lining structure in the single wall and the upper / lower overlapping tunnel set in the middle of the high side wall. The invention also provides the constructing method. The invention can build the two-line tunnels in the limit room under ground and decrease the environment influence, the underpinning number of the pile foundation and the cost.

Description

Technical field: [0001] The invention relates to a subway overlapping tunnel structure-a single-hole double-layer overlapping tunnel and a construction method thereof. It belongs to the field of underground engineering. Background technique: [0002] In the construction of underground railway projects in high-density high-rise building urban areas, due to the criss-crossing of underground pipelines and the dense distribution of underground buildings (structures) such as pile foundations, the underground space is very limited and wiring is difficult. In order to meet the requirements of passenger traffic, the subway line needs to adopt a double-line line, and its layout forms are various, mainly including a single line with two lines in parallel, a single line with two lines in parallel, and a single line with two lines overlapping. Tunnels pass through underground pile foundation groups. When the underground corridor is limited and the tunnel width is limited, the structure...

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Problems solved by technology

[0003] 1. The excavation of the tunnel twice has a great impact on the surrounding buildings of the tunnel;

[0004] 2. The two holes are constructed by the positive step method. Due to the overlapping of the upper and lower small intervals, the mutual influence is serious, and the force and deformation are complicated;

[0005] 3. It is necessary to reasonably select the upper and lower construction sequence and construction interval, the process is complicated, it is not easy to install groups, and the construction is difficult;

[0006] 4. The weakness of the sandwiched soil between the double-holes with ultra-small net distance is the Achilles’ heel of the double-hole overlapping tunnel. The sandwiched soil is disturbed by multiple excavations and under the vibration load of the train during operation, the strength decreases and the self-stability changes. very limited, thus affecting the safety of the entire structure

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