For the design of a pile foundation subjected to lateral load, the linear subgrade reaction method, which is commonly called Chang's. solution, is widely used in Japan. However, the solution is not applicable to soils, such as sand, where the stiffness increases approximately linearly with depth. In practice, the estimate of such subgrade reactions has not also published. This report presents the relationship between the coefficient of the horizontal subgrade reaction from the back analysis of twenty-eight full scale tests on a pile in sand and N-value measured by the standard penetration tests.
