A small-strain soil constitutive model for initial stiffness evaluation of laterally loaded piles in drained marine sand

Abstract

Three-Dimensional Finite-Element Method (3-D FEM) analyses were performed to investigate the initial stiffness of the laterally loaded piles in drained marine sand. A small-strain soil constitutive model developed based on Menq model was implemented in the 3-D FEM model to simulate the response of laterally-loaded piles in the sand over a range of small displacements. The model incorporated how the shear modulus for sand increased with the mean effective stress and decreased non-linearly with the increasing shear strain. The procedure of calibrating the model was proposed based on fitting the measurements from both laboratory tests and in-situ site investigation This soil constitutive model was implemented within a 3-D FEM analysis using an isotropic material with strain-induced anisotropy behavior in order to simulate the response of laterally-loaded piles under monotonic loading. A comparison of model predictions with laboratory and field test results indicated that this model had the promise to simulate the non-linear relationship between lateral load and pile-head deflection for mudline deflections ranging from less than 0.25-percent of the pile diameter.