Abstract: The combined action of the deep excavation supporting structure, internal struts and the adjacent soils is numerically simulated by using MIDAS GTS software. A deep excavation in the first terrace of Yangtze River used cast-in-pace bored tangent piles plus internal strut as the supporting structure and its three-dimensional finite element analysis model with modified Mohr-Coulomb constitutive soil model is established. The entire excavation process was numerically simulated under the assumptions of artisan and non-artisan groundwater conditions. The deformation and internal force variations in the supporting structure during the excavation, strut installation, and dewatering process are simulated. The impact of the dewatering on the excavated area and the settlement of adjacent soils are evaluated. The deformation and stress of the supporting structure including the horizontal struts under various working conditions are discussed. The analytical results provide technical supports for the excavation optimization design.

Key words: First Terrace of Yangtze River, Deep Excavation, Soldier Piles, Internal Support, Numerical Simulation, Artisan Groundwater