Analytical solution for consolidation of composite ground with impervious pile

Based on the axisymmetric consolidation model, an equation governing the consolidation of composite ground with impervious piles is obtained. It is proved theoretically that only vertical flows will occur within the surrounding soil during the consolidation of ground reinforced by impervious piles. In addition, the variation of the horizontal permeability of soil due to the pile construction has no influence on the consolidation of ground. Analytical solutions are then derived for the consolidation of composite ground subjected to an instant loading and a ramp loading, respectively. The consolidation behavior of foundation reinforced by impervious piles is subsequently investigated. The results show that the consolidation rate of composite ground with impervious piles is greater than that of the natural ground, but is less than that of the composite ground with granular piles; and with the reduction of the radius ratio (radius ratio of the influence zone to the column) or the increase in the pile-soil compression modulus, the consolidation rate is accelerated. There is an optimal value for the influence of the radius ratio on the consolidation rate. When the radius ratio is larger than this optimum value, the consolidation rate of ground is almost not changed. The loading period has a greater influence on the consolidation rate. The longer the loading period is, the rapider the consolidation rate is.