Abstract
Expansive soil is highly susceptible to water loss and shrinkage cracking in dry conditions, resulting in the formation of crisscrossed cracks during tensile failure. This significantly compromises its engineering properties across various fields, including geotechnical, water conservancy, environmental, and agricultural engineering, and can trigger a range of geological hazards. To investigate the impact of initial water content, thickness-to-width ratio (the ratio of the sample's thickness to its side length), wind speed, and light intensity on water evaporation and crack development, drying and cracking tests were conducted on expansive soil specimens using homemade experimental setups and image recognition processing technology under controlled conditions. The findings reveal distinct stages in soil water evaporation and fracture development. Specifically, the initial water content greatly influences fracture generation and development, with higher initial water content leading to faster water evaporation during drying and an extended time for fracture stabilization. Additionally, the thickness-to-width ratio plays a significant role in water evaporation rate, correlating with crack area size and inversely correlating with crack length. Furthermore, ambient wind speed and light intensity promote water evaporation, accelerating crack generation to some extent, albeit with minimal impact on stabilized crack area. These research outcomes provide crucial insights for preventing and mitigating engineering geological issues associated with expansive soil drying and cracking.