Numerical simulation of deep penetration of a Piezocone in a strain-softening clay

This paper presents a numerical model which has the ability to simulate Piezocone penetration starting from the ground surface in saturated soft clays. The constitutive behavior of the soil is modeled using the Modified Cam Clay model and the model has been verified using centrifuge model tests. The variation of cone resistance is examined with various parameters, which influence the penetration resistance of the cone, such as rigidity index of the soil, in situ stress anisotropy, roughness at the cone-soil interface and the overconsolidation ratio of the soil. A correlation has been developed incorporating the influence of above parameters on the Piezocone resistance and results are compared with previous correlations based on the finite element method. Finally, the strain-softening behavior of the soft clay on the penetration resistance is investigated. The brittleness or sensitivity of the soil increases with the increase in degree of strain-softening but the results do not show significant reductions in computed cone penetration resistance. The cyclic penetration tests simulated using the proposed model show that the Ball and T-bar penetration tests are better than Piezocone test in predicting the degree of soil sensitivity.