Effect of crack on soil damage response induced by wetting

Desiccation cracks due to drought can significantly weaken soil engineering properties around cracks and induce shallow landslides after rainfall. However, to date, no known studies in the literature present a comprehensive investigation of the soil failure mechanism with desiccation cracks during rainfall. In this study, a series of water infiltration tests were performed on cracked soil specimens with different initial crack sizes. Photogrammetry and particle image velocimetry (PIV) were employed to enable efficient and non-destructive recording of soil morphology and displacement of specimens during wetting processes, and the evolution of crack morphologies and the associated damage to surrounding soils over time was examined. Results indicated that the soil damage response around cracks during the wetting process could be categorized into three stages: in a swelling stage, the crack depth remained unchanged while the crack width decreased; in a collapse stage, soil particles began to collapse, and quickly filled the crack; in a stable stage, the crack shape tended to stabilize. Moreover, the soil damage response was highly related to the initial crack shape. For the specimens with the same crack width, an inverted bell-shaped pattern was identified for those with a deeper crack due to the preferential water infiltration into the crack and the softening of deep soils. By contrast, at a given crack depth, the specimens with a larger crack width exhibited higher wetting resistance. The study provides informative ideas and valuable insights on the desiccation crack development and its role in earth structure stability during the entire drought-rainfall processes.