Numerical Simulation And Design Method Research Of Composite Soil Nailing

Composite soil-nailed wall (CSNW) is composed of leading support, soil nails and retained soil. In recent years, it is widely used in the application of deep excavation in soft soil areas, such as Shenzhen, Shanghai, Hangzhou, and many other places in China. It is verified by practice to be cost-efficient and time-saving.Although CSNW has been successfully used in many deep excavation projects, its working behavior has not been clearly understood. Meanwhile, the current design method couldn't properly take account of the function of the leading support, resulting in the uncertainty of the safety of the designed project. For the sake of disclosing the behavior of CSNW and improving the current design method, the main works included were as follows.(1) On the basis of former research and practice carried out by other researchers and engineers, the definition of CSNW was clearly illustrated. As well, the structural composition and working characters of the components were introduced systematically.(2)Based on non-linear finite element method, taking use of commercial code -ABAQUS, numerical analysis was carried out to study the working behaviour of CSNW in soft soil, including ground deformation and stress distribution in soil nails. By comparing with simple soil nailed wall's simulation, the function of the leading piles in CSNW was analysed.(3)According to the results of numerical simulation, some proper hypothesis was introduced. Based on limit balance analysis, the current design method was modified to be applied to CSNW design. The method of calculating the safety factor of global stability, anti-overturn stability, anti-slippage stability were proposed.