In order to improve the design and calculation of laterally loaded piles

finite difference numerical analysis method which can calculate displacements and internal forces of piles under lateral load of trapezoid distribution is proposed based on nonlinear p - y curve mode of foundation coefficient. The finite difference formulations of displacements of piles are deduced in detail. Based on these formulations

computation and visualization programs of displacements

internal forces of piles and soil reaction are developed for design calculations of anti-slide piles and cantilever retaining piles for deep foundation pits. Taking the new pile cast-in-situ concrete thin-wall pipe pile (PCC pile) as anti-slide pile

a comparison study is computed. The examples show that this method is convenient and reliable. Numerical solutions are close to real solutions when finite differential segments are small enough.