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Abstract A 3D finite element analysis of the temperature field by freezing method adopted in the preparatory plan for the shield tail brush replacement after long-distance excavation in the Shanghai Yangtze River Tunnel is given to show the feasibility and reliability of the special program of the freezing method. According to the shield tail brush replacement plan by freezing method，in conformity to the geological conditions，structure of the shield machine and the segments and the thermo-dynamical properties of the sealant-grease and other related media，with the replacement technology taken into account，the temperature field during the tail brush replacement process is computed by the software ANSYS for analysis of the growth ratio，the thickness development and the watertightness of the frozen soil zone. The results demonstrate that the frozen soil ring can come into a closure state in a short time after the freezing process starts and then develop steadily. It is also shown that the frozen body will be weakened when the segments of the temporary ring are removed but it can soon go on growing and turn into a safe state. The conclusion is that the tail brush replacement plan by freezing method is feasible and reliable.
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Received: 03 September 2008
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