Due to the fixed negative charges in the skeleton of expansive soil

there are exchangeable cations between the layers that balance the negative charges in expansive soil. That makes the soil exhibit strong expansion and shrinkage properties. The research results show that the expansion and shrinkage of expansive soil will be affected by the chemical composition of the pore solution. In this paper

based on the strong expansive soil in Guangxi

a series of tests are carried out to investigate the soil-water retention curve (SWRC) and the soil shrinkage curve (SSC) for the soil saturated with solutions of different NaCl concentrations. To address this issue

the concept of intergranular stress is introduced

which takes into account the effects of osmosis

capillary

and adsorption. The results show that pore saline solution affects the SWRC through osmotic suction

with a lesser effect on matric suction. The shrinkage deformation of soil samples during the drying process is controlled by intergranular stress

similar to the phenomenon of pressure-induced consolidation. The majority of shrinkage occurs during the capillary stage

exhibiting elastoplastic deformation; less shrinkage occurs during the adsorption stage

which is characterized by elastic deformation. A cutoff point on the compression curve is identified to distinguish between the regimes of capillarity and adsorption

consistent with the independently measured SWRCs at different compactness. The intergranular stress is shown to better describe the chemo-mechanical behavior of expansive soil

particularly at low water content.