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| Analysis of Mechanical Characteristics for Lining of Existing Metro Tunnel upper Crossing by Close Range Excavation Passageway in Loess Region |
| WANG Jun - qi1, KANG Zuo1, ZHAO Jie2 |
| (1. Xi’an City Metro Co. Ltd， Xi^an, Shaanxi 710018， China; 2. Key Laboratory for Bridge and Tunnel of Shaanxi Province，Chang'an University，Xi'an, Shaanxi 710064，China) |
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Abstract Research purposes ： In order to understand mechanical characteristics for lining of existing metro tunnel upper crossing by close range excavation passageway in loess region，relied on the project of m - C to n - B passageway of Taibai South Road Station of Xi an metro line No. 3, based on the field tests， this paper analyzed the contacting pressure between initial supports and secondary linings and stress of secondary linings of existing metro tunnel.
Research conclusions ： ( 1 ) The contacting pressure between initial supports and secondary linings of existing metro tunnel in earlier crossing line on the whole is smaller than in later crossing line, and in one tunnel case the pressure on the construction surface side is greater than on the other side. (2) The contacting pressure of each monitoring point in left and right lines is increased in the construction process of upper crossing passageway， and the increase range of monitoring points in later crossing line is more than in the earlier crossing line. ( 3 ) Influenced by the change of upper crossing passageway height， the secondary linings of the earlier crossing line presents the trend twist to the left， the stress of the left side is pressure stress and the right side is first pulling stress after to pressure stress. (4) The stress of scondary linings of later crossing line is basically symmetrical，which on the whole is larger than the earlier crossing line. (5)The research results can provide reference for the design and construction of similar engineering in loess region.
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Received: 24 July 2015
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2015, Vol. 32 
