Analysis Of Braced Retaining Structure With Double-row Piles

Retaining structure with double-row piles has been widely used in deep excavation., However, the studies on their behaviors have been mostly concentrated on cantilever structure. The references on braced retaining structure with double-row piles have been rarely reported. This paper is concerned with the mechanical and deformation behaviors of the braced retaining structure with double-row piles by 2D FEM. A model based on beam-spring models is proposed for the design of retaining structure. The main work includes:1. According to the current calculating models of cantilever retaining structure with double-row piles that based on beam-spring models, finite difference method programs are developed respectively. The application of the structure in a case is introduced. The differences between the calculated results by those models are compared. Based on the observation data, the most reasonable model is presented, and some influencing factors have been analyzed. The conclusions are very useful for optimum design of the cantilever retaining structure with double-row piles.2. The basic theory of the plane strain FEM is introduced. The functions, program verification of software ANSYS and the key-processes of the numerical experiments for excavations in which braced retaining structure with double-row piles are applied are also described.3. The application of the braced retaining structure with double-row piles in a case is introduced. The behaviors of the structure are analyzed by 2D FEM. The constitutive behavior of soil is elasto-plastic. The effects of the length of back-row pile, back-row pile space, distance between the two rows of piles, reinforcement of the soil, top beam stiffness, brace stiffness have been analyzed as well. The distribution of the earth pressure against the retaining structure has been derived.4. According to the theoretical distribution of the earth pressure, a method based on beam-spring models is proposed for the design of braced retaining structure with double-row piles. Field measurements of deformations from the excavation case in Hangzhou provide an opportunity to access the validity of the model.