Analysis of soil shrinkage characteristics and dry shrinkage deformation mechanism on digital image processing

Soil water variation in desiccation process will cause soil shrinkage deformation, this leads to the settlement and cracking of the structure. Especially for the clay containing more hydrophilic minerals, the change of water content has a significant effect on its mechanical properties. By controlling relative humidity in the environment chamber, shrinkage deformation tests were carried out to explore the influence of water content on soil shrinkage deformation, especially clay soil. The shrinkage characteristic curves of the three soil samples show that, at the stage of proportional shrinkage, Denver Claystone and Sanmenxia Clay exhibit significantly higher volume change than Zhengzhou Silt. However, the difference of volume change between Denver Claystone and Sanmenxia Clay was not significant, which was about 21 % of the total volume change. But the shrinkage rates of the three soil samples were higher in the proportional shrinkage stage. Meanwhile, from the microscopic of pore water retention form in soil, analyzed the mechanism of shrinkage deformation in capillary stage and adsorption stage during evaporation process, and the reason of the obvious non-zero shrinkage stage.