The design of piles to resist lateral loading is an important problem in soil structure interaction. Several methods, based on different theories, have been suggested for analysis of such foundations. Taking into account the nonlinear and inelastic characteristics of soils, the p-y method of analysis is thought to be the best one at the present time. A principal feature of the p-y method is the solution of a nonlinear, fourth-order differential equation by finite-difference techniques. The soil is modelled by the use of discrete mechanisms (p-y curves), which relate the soil resistance to the pile deflection at various depths below the ground surface.

To provide a means of evaluating the difference-equation method employing p-y curves, the method was used to predict the response of a number of piles where experimental data were given in the technical literature. Predicted results were compared with those from the experiments. The comparisons show fair to excellent agreement.

The p-y method of analysis has been used extensively for the analysis of piles that support offshore structures. The method is being improved as results become available from recent research; however, data from a number of well conceived experiments with fully instrumented piles are needed.