Finite-Element Modeling of Cone Penetration in Soft Clay at South Bandung, West Java, Indonesia

Abstract

Piezocone is one of the most useful tools to identify soil conditions, especially when the ground is soft. The interpretation of the results is quite challenging because it requires knowledge and understanding of the cone penetration mechanism. In this study, a numerical model based on the finite-element method was used to study the soil response of a soft clay located in the Bandung basin, West Java, due to cone penetration. Geologically, this soil is identified as lacustrine that has unique characteristics. Its liquid limit (LL) and void ratio (e) are exceptionally high, that is, up to 200% and 8.0, respectively. Therefore, it is categorized as highly plastic and highly colloidal clays. Nine cone penetration simulations have been conducted, and the simulations have been performed by adopting a press-replace method (PRM). The calculated cone resistance (qc) and pore-water pressure (u2) are compared with the measured data. Furthermore, the undrained shear strength of the soil (su) was also predicted using the cone factors Nkt and NΔu. Using the values of Nkt=13 and NΔu=10, a good agreement was obtained. Moreover, investigations on the stress path behavior due to cone penetration were performed. A simulation of the dissipation test was also carried out to study the decay of excess pore pressure and to estimate the soil permeability. The predicted results show a good agreement with the measured data.