Simplified Shockwave Analysis of the Standard Penetration Test

Abstract

The one-dimensional wave equation is used to develop a simplified analysis of the standard penetration test (SPT), including the phenomenon of hammer bounce. The analysis identifies the main dimensionless variables involved. Results suggest that a large part of soil resistance is due to damping rather than soil strength. Results confirm recent findings from experiments that significant energy inputs can occur at the second and subsequent impacts; this can affect several factors including those for rod length correction and in a liquefaction-resistance assessment that uses SPT. Opportunities for further investigation of the SPT apparatus are discussed.