Abstract: The soldier pile lagging with concrete internal strut is a common supporting structure in the deep excavation. Most of the soldier pile supporting structures have a straight-line layout due to their simplicity and the construction convenience, however, the stiffness of the straight-line layout has difficulties meeting the requirements of supporting large excavations. This paper presents a case history of a large sized deep excavation supporting design for an underground parking garage in Wuhan. the horizontal deflection at the pile head during the progress of the excavation of both the staggered and straightline soldier pile layouts are numerically analyzed and evaluated. The design parameters and optimized layout for the staggered soldier pile supporting structure are proposed based on the site-specific subsurface conditions. The comparison of the construction monitoring and numerical simulation results indicates that, the maximum lateral deflection in the staggered soldier pile supporting is 3.8 mm and is located at the middle of the exposed supporting structure. The lateral deflections in the staggered soldier pile wall meet the design requirements.

Key words: Deep Excavation, Soldier Pile Layout, Staggered Soldier Pile Layout, Numerical Simulation