The Space Linear Finite Element Analysis Of Retaining Structures For Deep Foundation Pits

With the development of economices in China, a great deal of tall buildings and substructures are constructed, and the excavations are becoming more and more. The design and construction of the excavation are becoming more and more difficult. Now, the theories and the calculating methods of retaining structues for deep foundation pits in the home and abroad chiefly include the limit equilibrium method, the subgrade reaction method and the finite elemenet method. The limit equilibrium method cannot meet engineering design demands frequently as too much factors ignored, and the application is becoming less and less. The finite element method is mature in theory, but it is difficult to fix the earth model and the soil parameters, so being difficulty to be practically applied. The elastic-reaction method is used more and more in recent years, but it is only apllied in design and calculating of plane retaining structure and ignored the spatical effects of retaining structure for foundation pits.Space elastic-reaction method is based on plane elastic-reaction method. Comparing with plane elastic-reaction method, space elastic-reaction method can be applied for three-dimensional calculation of foundation pit's retaining structure. However, the architectural characteristic of foundation pit's retaining structure can be different from another, and space elastic-reaction method cannot apply for all retaining structures for foundation pits. In this paper, basing on the architectural characteristic of foundation pit's retaining structure composed of concrete diaphragm wall and bracing system, revised space elastic-reaction, the space linear finite element analysis method aiming at researching the stress and strain of foundation pit's retaining structure is proposed. This paper doesnot only describe the space linear finite element analysis method for deep foundation pit's retaining structures, but only give a practical sample's analytic process by applied this method.Above-mentioned research findings can provide references for design and construction of deep foundation pits.