Abstract: Method for nonlinear consolidation of underconsolidated clay under arbitrary loadings is paramount in engineering practice; however, few solutions in this area have been available. By the method of Laplace transform, according to the Gibson’s governing equation for one-dimensional consolidation of saturated thick clay layers, a short paper has studied the behavior of this kinds of soils. Results are presented by the inverse Laplace transform. The solutions manifested that the degree of consolidation and the settlement are depended only on the parameter (governing equation parameter), and the development of the degree of consolidation as well as the normalized void ratio is a vibrant process under arbitrary loadings such as cyclic loadings, the degree of consolidation lags the imposed loadings and the amplitude does not reduce as time goes on. Method presented in this paper can be adopted to calculate the degree of consolidation and the void ratio of underconsolidated saturated soft soils under arbitrary loadings at any instance T with different boundary conditions (pervious and impervious). The results are meaningful in engineering practice.

Key words: nonlinear, underconsolidated, arbitrary loading, Laplace transform