Usually the effective stress analysis will provide a lower allowable bearing capacity for very stiff
or hard saturated plastic soils. This is because such plastic soils are usually heavily overconsolidated
and they tend to dilate (increase in volume) during undrained shear deformation. A portion of the
undrained shear strength is due to the development of negative pore water pressures during shear
deformation. As these negative pore water pressures dissipate with time, the shear strength of the
heavily overconsolidated plastic soil decreases. For the long-term case (effective stress analysis), the
shear strength will be lower resulting in a lower bearing capacity.