Numerical modelling of pile jacking in a soft clay

The soil strength and stiffness around a pile can change significantly due to the installation process. This paper presents numerical modelling of pile jacking in soft clay using the Press-Replace (PR) technique and the S-CLAY1S (anisotropy and structure) model. The soil parameters in the finite element analysis represent Bothkennar clay. Numerical load tests were performed to compare the axial response of the pile installed (using PR) and the pile wished-in-place. In addition, the simulations were repeated using the S-CLAY1 (anisotropy) and the MCC (isotropic) models for comparison. The effect of anisotropy, bonding and destructuration of Bothkennar clay were investigated for pile capacity. The results demonstrate that bonding and destructuration have influence on the pile capacity, especially if the installation effects were considered, i.c. simulating the penetration phase by the PR method.