Effect of temperature on swelling pressure and compressibility characteristics of soil

Clays are being used for several construction purposes particularly as waste isolation barrier and undergo several temperature and hydraulic condition during operational period. Clays may undergo large compression during the particular loading condition. Bentonite is highly swelling clay containing high amount of montmorillonite mineral is considered as barrier and backfilling material for high level radioactive waste disposal repositories. The present study investigates the effect of temperature on swelling pressure and compressibility behavior of divalent rich Indian bentonite (liquid limit = 139%) from Bikaner, Rajasthan and effect of temperature on compressibility behavior of local soil (liquid limit = 35%) from Rourkela. A new oedometer was designed and developed in-house to carry out consolidation and swelling pressure tests at various temperatures. Swelling pressures tests on compacted bentonite specimens of targeted dry density 1.6 Mg/m3 were conducted under constant volume condition for the temperature range between 25 and 90 °C. Consolidation tests at various temperatures between 25 and 90 °C for both soils were carried out using distilled water as inundating fluid. The study revealed that with increase in temperature the swelling pressure and compressibility index of bentonite increased. However, effect of temperature on compressibility behavior of local soil was found to be minimum.