Author(s): Wang Lifeng, Zhu Jianghong, Luo Jinhong, Ma Jian
Pages: 197-201
Year: 2013 Issue:  9
Journal: Bulletin of Science and Technology
Keyword:  shield construction; surface settlement; settlement trough;
Abstract: Hangzhou metros are being constructed mainly in such silt and mucky soil as soft layers. Longitudinal and traverse surface settlements and variation law, settlement scope, settlement trough and relationship between maximum settlement and tunnel depth are analyzed during Hangzhou shield construction based on field datum. The results show that surface settlements are divided into such three stages as 0~40 m before shield machine, 0~50 m after and post-shield construction stage according to settlement magnitude and location of shield machine. Longitudinal settlement scope is 40 m before, 50 m after machine, and traverse scope is each side of 20 m of machine. Surface settlements ,which are mainly caused at stage of 20~50 m after shield machine ,as well as heaves , can be seen during shield construction while settlements accompanying upheavals are stable at stage of post-shield construction. Settlement trough coefficients increase with tunnel depths, and maximum settlement decreases with depth. The gained conclusions have theoretical significance and guidance for design, supervising and shield construction.