Bench-Scale Study of Desiccation Crack Development in Clayey Soil

Desiccation cracks play a crucial role in the stability of slopes by impacting mechanical and hydraulic soil properties in upper layers of the slope. Research involving a bench scale device for studying desiccation crack development is presented in this paper. The bench scale device contained a compacted clay soil bed approximately 0.9 m deep and instrumented with five soil moisture sensors at different depths. In plan, the soil bed was 0.6 m long and 0.1 m wide, and constrained at the ends so that transverse desiccation cracks would form. The sides were constructed of clear acrylic so that crack depths could be monitored. A soil water characteristic curve was determined so that total suction variations in the soil bed could be estimated using moisture contents. After 1.5 months the soil moisture loss became gradual and exhibited a similar steady rate at all depths. Measured crack depths at the end of 5 months compared favorably with those predicted using a simple analytical model.