Size effect on soil desiccation cracking

Soil size significantly affects its desiccation cracking behavior, influencing both cracking pattern and associated mechanism. Although previous studies have qualitatively explored cracking in soils of varying sizes, a good understanding of how size specifically influences these patterns remains limited. This study addresses this gap through desiccation tests on strip and slab soil specimens with varying heights, widths, and height-to-width ratios. Evaporation rates, shrinkage behavior, and cracking patterns of the specimens are analyzed. Results reveal that soil size governs desiccation cracking by affecting evaporation rates and shrinkage-induced stresses. The evaporation rate drives the extent of shrinkage deformation, with differential shrinkage across dimensions generating tensile forces either at the container base or on the soil surface. These forces produce three main cracking patterns: parallel, networked, and transitional. The height-to-width ratio emerges as a reliable index of size effects on cracking patterns, with both high (>1.0) and low (<0.33) ratios producing networked cracks, while moderate ratios favor parallel cracks. This study enhances our understanding of size-dependent desiccation cracking in soils, offering insights applicable across diverse environmental conditions.