Desiccation crack depth and tensile strength in compacted soil

Considering desiccation cracks is important in the stability analysis of earthen slopes subjected to drying and wetting climatic events. To incorporate desiccation cracks into the analysis requires knowledge of the expected depth and distribution of cracks. In this paper, a simple method for estimating the depth of desiccation cracking in compacted soil based on elastic theory is presented, and an innovative method for determining tensile strength of desiccating soils is discussed. Measured tensile strengths compared favorably to predicted strengths based on a Mohr-Coulomb model that incorporates a microstructurally based effective stress to account for differences in macropore and micropore degrees of saturation. Predicted crack depths were reasonable compared to field observations, but predictions can vary depending on estimated soil parameters. An example of a preliminary approach to slope stability analysis incorporating desiccation cracks is presented.