Study of Failure Cases Due to Shield Tunneling

• Main Authors: Kuo-Feng Chain, 簡國峰
• Other Authors: Yung-Show Fang
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/51803261340757560833

碩士 === 國立交通大學 === 土木工程系 === 91 === In this paper, fourteen cases associated with failures of shield tunnels have been collected and discussed. Based on the experience accumulated, it is hoped that the designers and contractors will not make similar mistakes again. In the first part of this paper, case histories associated with the construction of shield tunnels at Bangkok, Mexico City, Washington D.C., Los Angeles, Romania Bucharest and England Kingston-upon-Hull are studied. In the latter part of this paper, geological conditions, causes of failure, and remedial works related to the shield tunnelling of Taipei MRT Hsintien Line lot CH221 and Panchiao Line lot CP261, CP262 ,CD266 are investigated. Base on the studies, major causes of failure of soft ground tunnels can be summarized as follows. 1. Choosing inappropriate construction method. For the tunnelling project at Mexico City, such as using an open-type shield in a very soft soil layer, and proceeding the tunneling construction under no soil improvement. 2. For the tunnelling project at CD266, the effect of the jet-grouting could be influenced by the following factors: （1）Poor quality of the ground improvement operation.（2）Variability of the subsurface could caused discontinuity and inefficient diameter shape in the jet-grouting soilcrete at the departure and arriving sections for the shield machine. （3）The vibration caused by excavation of the station could formed some cracks between the jet-grouting soilcrete and the diaphragm wall for shield tunneling.（4）The vibration caused by break through of the diaphragm wall for shield tunnelling could be a highly dangerous operation and might form some cracks in the jet-grouting soilcrete. （5）The presence of buried driftwoods could also caused discontinuity in the jet-grouting soilcrete.