A quasi-equal strain solution for the consolidation of a rigid pile composite foundation under embankment loading condition

Abstract

Based on the deformation characteristics of rigid pile, a quasi-equal strain assumption was proposed to analyze the consolidation properties of a rigid pile composite foundation. By considering the parabolic distribution of the horizontal permeability of the surrounding soil, the initial consolidation stress difference in the underlying stratum and the time and depth dependent additional stress, analytic solutions for the consolidation degree were derived. The analytical solution was compared to the numerical simulation obtained from the standard finite element method which validates the accuracy of the proposed analytical method. Furthermore, the factors that affect consolidation properties were systematically analyzed. The results show that the consolidation rate for a rigid pile composite foundation was slower than that for a composite foundation with a granular column but was more rapid than that for a natural double-layered ground. The consolidation rate increases with the relative reinforced depth, the permeability coefficient, the ratio of the constrained modulus of the pile to that of the surrounding soil, the ratio of the area replacement and the ratio of the constrained modulus of the cushion layer to that of the surrounding soil. The consolidation rate increases with the decrease in the loading period and the pile-end resistance coefficient.