| With the development of Zhoushan city, more and more large scale and deep pit excavations appear. The geological conditions in Zhoushan area are complex, the water content of soils are high, the strength is low, and the thickness of the soft clay is large. these factors make the pit excavation unsafe and difficult. So. it is particularly important to choose the reasonable type of supporting structure in order to ensure the safety of the pit excavations and surrounding eviroment. In light of this, based on the studies on literatures published in home and abroad. combined with several widespread uses of foundation pit support types in Zhoushan area, the following work is carried out.First, the tipical geological conditions and the foundation pit support types which are commonly used in Zhoushan area are introduced. The soil within the depth of excavation in Zhoushan area is mainly soft clay with poor properties and thickness of 1-20 m. and the soil layer should be focused in the engineering design.Then the main analysis function, the main module, material library and element library in ABAQUS are summuried. The stress invariant, stress space, isotropic elastic model and the nonlinear porous elastic model which is applicable to simulate soil constitutive relation in ABAQUS are described. And the key technologies of simulating foundation pit excavation are introduced amphatically, such as the applying of initial stress field and element birth and death for simulating excavation process.Combining with three project examples and the corresponding physical model, the internal force and deformation of supporting structure and soil are studied on the condition of three types of supporting structure:cement mixing pile, soil nailing and pile-strut bracing structure, the conclusions obtained have some important reference value. Meanwhile, through the calculation and comparison, the paper summarizes some rules which are useful for the design and construction of the excavation in Zhoushan area.
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