89 / 2019-07-31 17:56:00

Experimental Research on Shrinkage and Cracking Characteristics of Clayey Soils

Clayey soil; desiccation cracking; sample size; fine content; wetting-drying cycle

水库地质灾害防治与生态环境保护 > 表生地质作用与地质灾害演化过程

Drying induced soil shrinage and desiccation cracking of clayey soils are common natural phenomena. A series of laboratory desiccation tests were performed to study the effects of sample size, fine content and wetting-drying (W–D) cycles on the cracking of clayey soils. In this study, initially saturated soil slurry samples were subjected to drying at a constant temperature of 60℃. The crack patterns at different water contents captured by a high-resolution camera were quantitatively analyzed using a software “Crack Image Analysis System” (CIAS). Experimental results show that most of the cracks initiate when the soils are still fully saturated and the corresponding critical water content at onset of cracking is likely higher than the liquid limit. The flaws on soil surface can result in stress concentration and trigger the initiation of cracks. The soil surface crack ratio and mass fractal dimension increase with an increase in the diameter of soil sample. For the soil sample with a higher fine content, the final surface crack ratio and the average width of cracks become larger. With increasing numbers of wetting-drying cycles, the cracks become more irregular and more short and narrow crack segments can be observed.