Abstract: At present, it is assumed that the consolidation coefficient of the soil remains constant for the nonlinear consolidation solutions of the double-layered soil considering the nonlinear compression and permeability of soil. There are few studies on the nonlinear consolidation solutions of double-layered soil considering the variation of consolidation coefficient. The classical e- and e- nonlinear relationships are introduced to describe the nonlinear compression and permeability characteristics of soil. Based on the assumption that the ratios of compression index and penetration index in both layers are the same and not equal to 1, the approximate solutions for one-dimensional nonlinear consolidation of the double-layered soil are obtained considering the variation of consolidation coefficient and time-dependent loading. Under the condition of 1, the solutions in this study can be degenerated to the existing one-dimensional nonlinear consolidation solutions of double-layered soil when 1. The influence of relative parameter ratios of the lower layer to the upper layer in double-layered soil on the nonlinear consolidation behavior finally is analyzed. The results show that, under the condition of single drainage, the nonlinear consolidation rate of the double-layered soil increases with the decreasing , the reducing relative compressibility, or the increasing relative permeability. When reduces or the thickness of the soil layer with low compressibility and high permeability increases, the consolidation rate of double-layered soil increases.

Key words: double-layered soil, nonlinear consolidation, variation of consolidation coefficient, analytical solutions