A numerical study of coupled consolidation in unsaturated soils

This paper first describes the numerical implementation of the coupled form ulation for the theory of consolidation of unsaturated soils. The developed computer code is verified using the Mandel-Cryer problem and then is appli ed to the solution of coupled multidimensional consolidation problems. Usin g a parametric study, it is demonstrated that, in unsaturated soils, the Ma ndel-Cryer effect is suppressed and the consolidation process in unsaturate d soils is affected significantly by the shape of the soil-water characteri stic curve. Finally, the developed model is used to analyze the consolidati on of an unsaturated-saturated soil column. Analysis results indicate that the classical "undrained" pore-water pressure response to an externally app lied load only occurs in the saturated zone while the pore-water pressure r esponse is subdued in the unsaturated zone. This paper also shows a method of deriving one of the two additional material parameters required for the analysis of unsaturated soils from laboratory test results.