Numerical Simulation of Pile Installation and Setup for Bayou Lacassine Site

During pile installation, the stresses and void ratios in the surrounding soils change significantly, creating large strains, soil distortion and excess porewater pressures. This makes the numerical modeling of pile installation process using finite element (FE) method a challenging task. In this paper, the pile installation process and the subsequent consolidation and load tests conducted at different times after end of driving were modeled for the Bayou Laccassine Bridge site. In the FE model, the pile was considered as an elastic material, and the modified cam-clay model was used to describe the behavior of the surrounding clayey soils. The surface to surface master-slave contact model was used to simulate the pile-soil interface. Pile installation was modeled by applying prescribed radial and vertical displacements on nodes at the soil-pile interface (volumetric cavity explanation), followed by vertical movement to activate the soil-pile interface friction. The results from the FE numerical simulation included porewater pressure generation and dissipation with time, increasing of effective normal stress at the pile-soil interface, and the setup ratios at different times. The results are compared with measured values obtained from the full-scale load tests on concrete piles, which showed good agreement.