Time-Dependent Settlement of Pile Foundations Using Five-Parameter Viscoelastic Soil Models

The present study predicts the long-term settlement behavior of pile groups using two different viscoelastic soil models, a linear five-parameter model (a Hookean spring element connected in parallel with two Maxwell elements in series) and a nonlinear five-parameter model (a Hookean spring element and two Maxwell elements all connected in parallel). The reliability of the models was assessed by comparing the results with available experimental and numerical data, and it was found to be within an error of 18% for the linear model and within an error of 3% for the nonlinear model. Parametric studies for 3x2 and 3x3 pile groups were carried out on the basis of parameters such as the distribution of shear stresses around the shaft over time, load resisted by the base over time, displacement of each pile element, and the effects of an enlarged base, the pile slenderness ratio, and pile group spacing. Interaction factors for the 3x2 and the 3x3 pile groups obtained by the linear and nonlinear five-element models were compared and shown to have a maximum difference of 7%. (C) 2018 American Society of Civil Engineers.