Lateral Static Response of Piles Based on a Full-Fledged Two-Parameter Foundation Model

A rigorous analytical continuum subgrade model translated into an equivalent two-parameter mechanical model of the Pasternak type is used to study the static response of piles to lateral loads. The model fully accounts for the soil shear missing in the conventional Winkler representation. The two parameters of the model are derived in advance. After conducting static analyses of a wide range of cases of the pile-soil system using both the proposed analytical model and finite-element models, closed-form relations are obtained for the adjustment factor left open in the model parameters that are found to mainly depend on the soil's Poisson's ratio. Back substitution of this factor showed that the model parameters take simple forms that depend only on a few factors such as the pile-soil stiffness ratio and the pile-end conditions. The model is validated by means of results of finite-element models. Closed-form pile head stiffness coefficients for various pile-end conditions are provided for both infinite- and finite-length piles. Expressions for a newly defined pile critical length are proposed for several combinations of pile-end conditions. It is demonstrated that the analytical approach employed is convenient and avoids the high degree of empiricity inherent in the conventional Winkler-based backward approach. The model has also the unique advantage of being convenient to conduct parametric studies, including the influence of soil shear resistance.