Abstract: This paper presents a case history of a deep excavation support project in the peat soil in Kunming. The influence of the deep excavation on the stability and the deformation of the soldier pile with ground anchor supporting system after the completion of the excavation is analyzed. A new reinforcement structure support system is then proposed. The FLAC3d numerical software is used to model and to analyze the horizontal and vertical displacements as well as the factor of safety of the overall stability of the supporting structure under three different loading conditions. The results show that the proposed supporting structure can be cost effectively applied to deep excavation in peat soil area. The construction period is shortened, and it has good economic and social benefits. The monitoring data of 114 times in 9 months are consistent with the numerical simulation results, which verifies the effectiveness of the composite reinforced structure system. The research results can solve the problem of the deep excavation after the construction of traditional supporting structure in the soft soil area, and provide a theoretical and practical basis for similar deep excavation supporting structure design.

Key words: Deep Excavation Support, Soldier Pile with Ground Anchor Support, Reinforcement, Peat Soil, Numerical Simulation, Excavations