Influence of wetting-drying cycles on crack behaviour in fine soils: An experimental study

Abstract Desiccation characterised by extreme drying, poses significant challenges to the stability of structures like dams, particularly those constructed on fine-grained soils. Extensive crack propagation in these soils can significantly compromise the structural stability and safety of the infrastructure constructed upon them. This study examines the desiccation cracking behaviour of fine soils samples under wetting-drying cycles and different environmental circumstances, replicating both intense outside heat and moderate inside temperatures. Two types of soil samples were prepared: silty soils obtained from the site and manufactured kaolin clay. Four series of samples, consisting of both types of soils, were employed in the experiment, each measuring 10 mm in thickness and examined in a 22 mm diameter desiccation tray. Two series were exposed to uncontrolled outside heat, while the other two were kept at a stable interior laboratory temperature. All samples underwent wetting and drying cycles in their respective settings, with the drying process observed until a constant mass was achieved. Crack intensity and propagation patterns were examined, highlighting the differences between outdoor and interior samples. The tests demonstrated that soil samples exposed to outdoor settings experienced higher temperatures and a rapid drying rate attributable to significant desiccation cracking, marked by high Crack Intensity Factor (CIF) values and complex crack patterns. The overall findings highlight soil moisture loss followed a steady linear trend under stable temperatures, but became unpredictable under variable conditions, affecting desiccation crack patterns. Temperature fluctuations intensified crack complexity and increased crack intensity in later cycles.