Numerical calculation of three-dimensional elastic wave equation of piles staggered grid finite difference using method with variable step lengths

To improve the computational efficiency of low-strain numerical simulation of piles, the variable step staggered grid finite difference method is introduced into the calculation of three-dimensional pile-soil model based on the traditional difference method. By differentiating three-dimensional elastic wave equation and introducing absorbing boundary conditions on the computational model interface, the low-strain numerical simulation of the response of piles is calculated under transient vertical excitating force. The results show that the computational accuracy is guaranteed and the computational process is more flexible and simple because of varied difference grids. The process can also reduce the memory requirements and the computational time. The absorbing boundary which absorbs the incident waves reaching the computational model interface is effective. The proposed method has achieved good effects on fitting low-strain measured curve and numerical simulation of asymmetric defective piles.