This paper presents a model to compute pressure and displacements in single piles under lateral load. The structure is solved by a soil structure interaction method (SSIM), which guaranties the displacement compatibility at the soil-pile interphase. The soil was modeled by rheological units that represent properly the stress-strain behavior of the soil, which means that stiffness reduces during the loading process without breaking the yielding criterion. The rheological units were built from an analogy with a block resting in equilibrium on a parabola plane, in which the pressure is related to the horizontal load required to keep the block in equilibrium, and the lateral displacement is equal to the length measured on the parabola from a reference position. Displacements are differed in time by a dashpot. The model was implemented in a computer programs and the results show permanent stress redistribution as the time increases under a constant horizontal load.