Analysis of CPT end resistance at variable penetration rates using the spherical cavity expansion method in normally consolidated soils

This paper presents numerical analyses simulating Cone Penetration Test (CPT) end resistance under various drainage conditions. The CPT end resistance was assessed using the spherical cavity expansion limit pressure evaluated in Finite Element analyses. These analyses employed coupled consolidation and a non-linear elasto-plastic model to represent the soil. The calculations are first compared with results from a series of experimental CPTs performed at variable rates in kaolin clay to demonstrate the potential of the numerical approach employed. A series of parametric numerical analyses allowed evaluation of the specific effects on penetration resistance of soil stiffness, friction angle, in situ lateral effective stress, stress level, permeability and cone diameter at various cone penetration rates. Use of a normalised velocity term incorporating a horizontal permeability, cone diameter and stiffness is shown to be an effective parameter to define drainage transitions.