Abstract: The frequently used deep excavation supporting methods in Wuhan are slope down with open cut, equal length soldier piles and passive zone improvement. However, the utilization of a uniform length of soldier piles in soft soils leads to an excessive construction cost. To reduce the excavation support cost, a case history of different soldier pile length is presented in this paper. The stress-strain relationship in the soldier piles with various lengths are evaluated by using ABAQUS finite element analysis and Tianhan commercial deep excavation software and compared with the excavation supported by the uniform length soldier piles. Both the monitored data and the analytical results are compared to validate the numerical simulation approach. Then, based on the validated uniform length soldier pile excavation supporting model, the threedimensional model with different length soldier pile excavation support was established by using ABAQUS software. The stress and deformation of four different types of soldier pile lengths are evaluated and the optimized soldier pile length arrangement is obtained through the analysis. Compared with the other model, the one long and one short soldier pile arrangement can effectively provide the excavation support.

Key words: Long and Short Piles, Deep Excavation in Soft Soils, Finite Element Method, Numerical Analysis, Passive Zone Reinforcement