Bentonite is often used as buffer and backfill material in deep geological repository because of its high swelling potential and low permeability

but its expansion characteristics will be influenced by solution concentration of underground fluid. In response to this phenomenon

the deformation characteristics of commercial bentonite under different loads and different concentrations of NaCl solution have been studied using uniaxial oedometer apparatus. The results show that with the increase of concentration of NaCl solution

swelling potential of bentonite significantly reduces

and there is a good linear relationship between the ma2016-01-08ximum swelling strain and overburden load in the log-log plot. Using the concept and calculation method of effective pressure

volume change behavior of bentonite in NaCl solution with different concentrations can be expressed by a unique curve

which also proves the rationality of effective pressure theory.