Undrained Bearing Pressure of Desiccated Non-homogeneous Ground Accounting for Compressibility

Normally consolidated soils have strength increasing with depth and with a desiccated layer near the top due to diurnal variations of temperature and weathering effects. Desiccated depth usually has high stiffness and strength which reduce to those values that correspond to the normally consolidated lower depth whose undrained shear strength increases linearly with depth. In this study, desiccated normally consolidated (DNC) ground was considered as a two-layer soil with non-homogeneities of these layers accounted for with decreasing and increasing rates of strength and stiffness with depth in top desiccated and the lower NC soil, respectively. A circular footing resting on desiccated zone overlying compressible NC deposit was analyzed considering the compressibility of the soils in the form of rigidity index. Bearing pressure–settlement responses of DNC are obtained by numerical analysis. Parametric study was carried out to study the effect of desiccation on undrained bearing pressure of footing on DNC. Bearing pressure of footings resting on DNC ground, increases with increase in rigidity index and non-homogeneity of NC soil. Thickness and non-homogeneity of desiccated zone significantly affect the ultimate bearing capacity of footing resting on DNC ground.