Validity of Smith Model in Pile Driving Analysis

Abstract

Smith developed a wave equation method by idealizing a pile‐soil system as a series of masses and springs for the analyses of complicated pile driving problems. The soil parameters used in this method were proposed on the basis of his experience in piling practice and hence, were recognized to be relatively crude from soil mechanics aspects. This paper presents results of an analytical procedure for determining the shaft damping parameter and relating it to the soil properties: (1) Shear modulus; and (2) shear strength. A dynamic finite element computer program is developed to analyze the pile shaft resistance by using an elasto‐plastic approach; the relationship between the shaft damping parameter and the other parameters such as pile penetration velocity, radius of yielding zone, and force pulse duration time are also examined. It is found that the Smith damping parameter cannot be back‐calculated to be some simple constant.