Measurements of ground settlements induced by the construction of a single tunnel mainly in soft clay of Ningbo Metro Line were presented. The soils above tunnel were mainly sandy silt and mucky clay, and the tunnel was constructed using earth pressure balanced (EPB) tunnel boring machine. Ground settlements due to shield tunneling were back-analyzed using the classical Gaussian empirical predictions, both in the transverse and longitudinal directions. Thus the transverse settlement trough parameters ix and K were obtained. Translated Gaussian cumulative curves were proposed to better match the evolution of settlements during tunnel advancement. The ground volume loss along the alignment was obtained, and the influence of excavation parameters on the volume loss was investigated. Results indicate that the total thrust force of the shield, normalized face-support pressure and backfilling grouting ratio can markedly influence the ground volume loss. Suggested ranges of different excavation parameters were presented．
LI Zhong-chao, CHEN Ren-peng, MENG Fan-yan, YE Jun-neng. Tunnel boring machine tunneling-induced ground settlements in soft clay and influence of excavation parameters. JOURNAL OF ZHEJIANG UNIVERSITY (ENGINEERING SCIENCE), 2015, 49(7): 1268-1275.
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