Abstract:
The statistical method is commonly adopted by many researchers for the estimation of the permeability function
of unsaturated soil. The statistical method is developed based on the assumption that the pores are randomly
connected to each other. Water can only flow through the water phase in those pores. In other words, the statistical
method is only applicable when the water phase in soil is in a continuous condition. However, past studies
indicated that the water phase in unsaturated soil became discontinuous when the soil suction goes beyond the
residual suction. When the water phase is discontinuous, the water in some of the pores may not be able to
provide the flow path because water cannot flow into the surrounding pores. Therefore, there will be a threshold
suction where the statistical method becomes inapplicable for suctions beyond this threshold value. In this
parametric study, the effect of the threshold suction on the estimated permeability function obtained from the
statistical method was investigated.