Creep settlement analysis of pile foundations using viscoelastic model by incorporating nonlinear soil behaviour

Abstract

ABSTRACT This study utilizes a nonlinear three-parameter viscoelastic model (a nonlinear spring in series with a Kelvin-Voigt element) to study the time-dependent creep behaviour in a single pile and group of piles. The method is based on modified Mindlin’s approach; and Laplace transforms have been utilized to simplify the viscoelastic problem into an equivalent elastic problem. The soil nonlinearity has been modelled by using a hyperbolic stress-strain relationship. The effects of parameters such as pile spacing, slenderness ratio and pile load factor on shear stress distribution, displacement of pile elements relative to the pile head, effects of enlargement of the pile base and interaction factors have been evaluated. The ratio of interaction factor for immediate and creep settlement is in the range of 0.4−0.9 for various pile groups. Since this study incorporates soil nonlinearity, the interaction factors increase by about 6%−10% when the pile load factor increases from 0.5 to 1.