Abstract: The case history of deep excavation project of a school reconstruction and expansion project in Binjiang District, Hangzhou City is presented in this paper. The combined form of Larsen steel sheet pile and section steel (HUI) are used to support the foundation excavation, and the lateral displacement of the support structure are monitored. The adjacent surface settlement and the diagonal slant support axial force during the deep excavation are also monitored. Results show that, compared to single Larsen steel sheet piles or SMW construction methods, the composite steel sheet piles can better meet the deformation control requirements of support structures and effectively reduce the surrounding surface settlements during excavations. Based on its advantages of convenient construction and recyclability, this composite steel sheet pile can be suitable for the deep excavation support in soft soil with larger excavation depths. This case history has a good reference significance for similar projects in other soft soil areas.

Key words: Monitoring, Deep Excavations, Steel Sheet Piles, Hot Rolled Steel