关键词: 膨润土, 膨胀应变, NaCl溶液, 有效压力

Abstract: 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.

Key words: bentonite, swelling strain, NaCl solution, effective pressure