A more direct method to model piles for the effects of lateral load and include soil structure interaction is to use a program called LPile, used by just about every Geotech that I know. This program utilizes input soil parameters, boundary conditions of the pile (fixed or free at the head of the pile in the cap) and calculates effective soil springs based on depth and material properties. The output will include displacement, shear and bending moment plots along the depth of the pile.