Abstract: The soil crack resulted by desiccation leads to many engineering and environmental problems.Taking bentonite with a high shrinkage rate for example,the soil desiccation and cracking tests are carried out.the results showed that the process of desiccation and crack were divided into three stages of pre-crackⅠ,rapid crackⅡ,and cracking stagnation Ⅲ.Cracking evolution is influenced by the boundary and relief of basement.At the early stage of rapid crackingⅡ,the cracking is mainly developing in the boundary of the model.However,in the late of crack,the cracking evolution is mainly influenced by relief of basement.In the stage Ⅲ,though the surface cracking still happens,the pattern of cracking development has not significantly being changed.The later cracks are approximately perpendicular to the early cracks,especially in the zone of basement from the view of the cracking shape.

Key words: Bentonite, Desiccation cracking, Cracks ratio, Relief of basement