Temperature effects on shrinkage properties of swell-shrink soils

The swell-shrink soils are prone to water loss, shrinkage and cracking because they contain more hydrophilic clay minerals, which have a significant impact on the engineering properties of soils. Taking two typical expandable soils (Guilin red clay and Nanning expansive soil) in Guangxi as the research object, the soil shrinkage tests are carried out at the temperature of 5℃~45℃. The effects of temperature on the shrinkage characteristics of the two types of expandable soils are compared and analyzed, and the mechanism of temperature effects on the shrinkage characteristics of the expandable soils is explained. The results show that: (1) The shrinkage characteristics of the two kinds of swelling and shrinking soils are significantly affected by the temperature. The shrinkage deformation of the samples increases first and then decreases with the increase of the temperature. There is a critical temperature 35℃. (2) The shrinkage deformation of the expansive soil is larger than that of the red clay, and the temperature effects are more significant. (3) The essence of the effects of temperature on the soil expansion and shrinkage are the change of soil microstructure and the change of water form in the soil. After reaching a certain temperature, the thermal expansion of soil particles and pore water caused by high temperature and the intensification of soil-water interaction make the soil skeleton have no sufficient time to transform into a compact state, which is the main reason for the decrease of shrinkage deformation.