Numerical study of rate effects in cone penetration test

The soil around a penetrating cone with the standard rate of 2 cm/sec could be fully drained, partially drained or fully undrained, depending on the permeability of the soil. Cone penetration tests with variable penetration rates in the same soil can thus provide additional information about the soil properties like permeability, or alternatively warrant the desired drainage condition when used to interpret the corresponding shear strength of soils with intermediate permeability values. In this paper, large deformation finite element analysis is used to study the effects of penetration rates on the cone resistance and excess pore pressure development. A rigid cone is pushed into a saturated soil by prescribing different penetration rates. The soil is modeled with the Modified Cam Clay model, and the effective stress analysis is carried out in terms of displacements and pore pressures. The numerical results are then used to develop empirical relationships between cone resistance, pore pressure and penetration rate.