Discrete-element based simulation of CPT and SPT on a volcanic sand

Abstract

In situ soil characterization often involves penetration tests. The response to both static and dynamic penetration in volcanic sands is known to be controlled by particle crushing, obscuring the effect of density and confinement on the response. This severely limits the use of penetration tests for soil characterization. In this work a virtual calibration chamber (VCC) built using the discrete element method (DEM) is employed to explore the relationship between cone penetration tests CPTs (static) and standard penetration tests SPTs (dynamic) results on a volcanic sand. The simulated CPT results are shown to capture well experiments from the literature over a range of density and confining stress. The comparison between the simulated CPT and SPT results shows good agreement with empirical expressions based on particle size. It was found that energy-based equivalent dynamic tip resistance obtained from the SPT is a good match for static cone tip resistance if shaft resistance effects are discounted. The results presented confirm the potential of DEM based VCC to examine the performance of in-situ tests in complex soil conditions.