Effect of Groundwater Salinity on the Hydro-Mechanical Behavior of Compacted Bentonite

A good understanding of the hydro-mechanical behavior of compacted bentonite is essential when evaluating the safe and effective operation of the high-level radioactive wastes management system. In this paper, the hydro-mechanical behavior of Gaomiaozi bentonite with different times synthetic water was investigated by the swelling pressure, permeability, and water content. Results show that the peak swelling pressure decreases rapidly when salinity is introduced. The compressed behavior of diffuse double layer induced by the high salinity solution is the main reason for the deterioration of axial swelling pressure and leads to an increase in the inter-aggregate pores, which expands the water flow channels inside bentonite and enhances the permeability coefficient. Also, the intrusion of hydration solution filled in technological void from the outside to the inner results in a gradient profile of water content. The present study will provide an effective reference for the establishment and improvement of the hydro-mechanical performances of bentonite under the complex chemical environment.