Abstract
The formation of desiccation cracks in clay has been understood based on tensile strength. However, this mechanistic model disregards the cohesionless, effective stress dependent frictional behavior of fine grained soils. We suggest an alternative theory using analyses, numerical simulations based on an effective stress formulation, and experiments monitored using high resolution time lapsed photography. New hypothesis assumes that desiccation cracks initiate as the air-water interface invades the saturated medium, driven by the increase in suction. Thereafter, the interfacial membrane causes an increase in the local void ratio at the tip, the air-entry value decreases, the air-water interface advances into the tip, and the crack grows. The effective stress remains compressive everywhere in the soil mass including at the tip of the desiccation crack.