Experimental investigation of osmotic suction effect on hydro-mechanical behaviour of remolded clay

The chemistry of pore water obviously affects the hydro-mechanical behaviour of clay, but the quantitative evaluation of pore water effect needs to be further conducted. The oedometer tests on kaolinite and Ca-bentonite mixtures saturated with different concentrations of NaCl solution are performed to investigate pore water chemical effect on the hydro-mechanical behaviour of remolded clay, where the osmotic suction is adopted as the characterization parameter. The results indicate that the compression index exponentially decreases with the osmotic suction, while the swelling index is almost constant. The compression behaviors after pre-yielding can be normalized in the I_v-lgσ^’_v system proposed by Burland, but it is not suitable before pre-yielding. There is a negative correlation between the secondary consolidation coefficients and the osmotic suctions, furthermore, the ratio of the secondary consolidation coefficient to the compression index decreases with the osmotic suction. The coefficient of C_k =Δe/Δlgk_v to depict the hydraulic conductivity is related to the initial void ratio and can be expressed as a function of the osmotic suction, which extends the understanding of this parameter.