Large deformation finite element simulation of deformation and strain fields resulting from closed-end displacement pile installation in sand

Displacement piles are driven to support a wide range of structures. However, analysis of the stress and strain fields developed during their installation remains one of the most challenging problems in geotechnical engineering. Advances in design methods, particularly for sand sites, have had to rely on an imperfect analogy between pile and CPT cone penetration processes, rather than modelling pile installation itself. Recent physical model experiments provide benchmark datasets that describe the stress and deformation patterns developed around displacement piles penetrating sand masses. Following from large deformation finite element analyses that captured the stresses measured in the Grenoble 3S-R calibration chamber NE34 sand experiments, this paper presents simulations of the displacements measured in equivalent high-quality experiments conducted at Purdue University with dense, angular, #2Q-ROK silica sand. A modified Mohr-Coulomb model with state-dependent parameters was calibrated to match element tests conducted by the Authors and an Arbitrary Lagrangian-Eulerian scheme was applied in the simulations. The evolution and distribution of the deformations induced by pile penetration are compared with the experiments. Predictions for the deformation and strain fields applying during and after pile installation are presented, showing broad agreement between the simulations and experiments. The predicted and measured pile capacities are also compared and contrasted. Points of divergence between the simulations and tests are highlighted and their implications for numerical modelling are discussed