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PERFORMANCE OF A DEEP EXCAVATION IN SOFT CLAY (2009)
The observed response of diaphragm wall and the surface settlement of a deep excavation for a metro station in Shanghai soft clay are presented, compared with the similar excavations (retained by a diaphragm wall) in soft clay areas in Asia and five metro station excavations (similar depth) in Shanghai. Results show that the maximum lateral wall deflection (δhm) and ground settlement (δvm) are 0.32% and 0.1% of final excavation depth (He), respectively. Lateral wall deflections are near the average magnitude value in Shanghai, smaller than those in Singapore. The largest lateral wall deflection is near the excavation center and the ratio of δhmcor/δhmcen of the maximum wall deflection is 0.39–0.74. The ground settlement is relatively small and falls in the Zone I limit described by Peck (1969). The adoption of prestressed steel struts, short excavation sections, fast workmanship sequences and compaction grouting may contribute to the deformation characteristics of deep excavations for metro stations in Shanghai.
Geotechnical Aspects of Underground Construction in Soft Ground – Ng, Huang & Liu (eds), © 2009 Taylor & Francis Group, London
Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education, Tongji University, Shanghai, P.R. China