Abstract:In order to improve the design and calculation of laterally loaded piles,numerical analytical method of finite difference is proposed which can calculate displacements and internal forces of piles under lateral load of trapezoid distribution based on biparameter mode of foundation coefficient. The finite difference formulations of displacements of piles are deduced in details. Based on these formulations,computation and visualization programs of displacements,internal forces of piles and soil reaction are developed for design calculations of anti-sliding piles and cantilever soil retaining piles for deep foundation pits. The examples show that this method is convenient and reliable. Numerical solutions are close to real solutions when differential segments are small enough. Calculation results of displacements and internal forces can perfectly coincide with measurements and practical values by trial computations with foundation coefficients adjusted. This method is used to obtain the foundation resistant coefficients by back-calculation with the data of testing piles given. The automatic visualization by the computer program is helpful to the optimization of structural design and hence the economic benefits.