Consolidation of clay by sand drain under time-dependent loading

The mathematical theory and physical laws of one-dimensional consolidation of clayey soils are well-known. Sand drains accelerate the consolidation process. Several analytical and experimental studies have already reported on sand drain consolidation of clayey soils. However, the literature does not contain a nonlinear theory of sand drain consolidation under time-dependent loading that can take into account any effective stress/void ratio/permeability variations. A generalized governing equation, capable of yielding a large class of analytical solutions for these variations is derived in this paper. Closed-form solutions are presented for the variation of pore water pressure with a time factor and load increment ratio under time-dependent loading. The analytical formulation is validated by comparing the solution with the standard results available in the literature for instantaneous loading, constant permeability, and constant compressibility.