Distinct element analyses of inclined cone penetration test in granular ground

Abstract

This paper is to investigate the mechanism of inclined cone penetration test (CPT) using the numerical discrete element approach. A series of penetration tests with the penetrometer inclined at different angles (i.e., 30°, 45°, 60°, 75° and 90°) were numerically performed. The velocity fields, displacements of soils adjacent to the cone tip, rotation of the principal stresses and the averaged pure rotation rate (APR) are analyzed. Special focus is placed on the penetration mechanism and the effect of inclination angle on the tip resistance. The DEM results show that soils around the cone tip experience complex displacement paths as the penetration proceeds and exhibit characteristic velocity fields corresponding to three different failure mechanisms. The principal stresses near the cone tip undergo apparent rotation, accompanied by large APR which indicates evident particle rotation adjacent to the cone. The normalized tip resistance qN( = qc/σν0) decays with penetration depth in a decreasing rate. At the same penetration depth, qN decreases with the increasing of the inclination angle of penetrometer.