盐溶液对膨润土膨胀性的影响

膨润土因其优良的膨胀性和低渗透性常被用作深层地质处置库的缓冲和回填材料，但其膨胀性会受到地下流体溶液浓度的影响。针对这种现象，利用单轴固结仪研究了压实商用膨润土在不同上覆荷载和不同浓度NaCl溶液作用下的膨胀变形特性。结果表明：随着NaCl溶液浓度升高，该膨润土的膨胀性显著降低，且最大膨胀应变与上覆荷载之间在双对数坐标系下存在良好的线性关系。利用有效压力的概念和计算方法，实现了用唯一一条曲线来描述不同盐溶液浓度作用下膨润土的膨胀变形行为，同时证明了有效压力理论的合理性。

Effect of salt solution on swelling characteristics of bentonite

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.