甘肃北山被首选为修建高放废物处置库的地区。考虑到该地区地下水中含有总溶解固体(TDS),选择NaCl-Na2SO4作为溶解固体。以高庙子钠基膨润土为试验材料,利用单向固结仪,进行不同TDS浓度盐溶液和蒸馏水饱和的膨胀试验。根据蒙脱石孔隙比的概念,统一整理了饱和高庙子膨润土在盐溶液和蒸馏水饱和下的膨胀特性。结果表明,当TDS浓度为12.3 g/L(预选处置库区的最高离子浓度)时,在双对数坐标中蒙脱石孔隙比与膨胀力关系和干密度与膨胀力关系均呈直线且平行于蒸馏水的试验结果;对于给定干密度试样,膨胀力的对数与TDS浓度呈线性关系。根据以上试验结果,给出了由高庙子钠基膨润土的设计干密度和离子浓度计算相应膨胀力和膨胀变形的表达式。
Beishan in Gansu province has been selected as the most potential area for the deep geological disposal of the high level radioactive waste. Considering the groundwater in the region containing the total dissolved solid (TDS), NaCl – Na2SO4 was chosen as a dissolved solid. In this paper, one-dimensional swelling deformation tests and swelling pressure tests were carried out on Gaomiaozi sodium bentonite saturated by the salt solution with different TDS concentrations and distilled water. Based on the concept of the montmorillonite void ratio, the deformation characteristics of Gaomiaozi Na-bentonite at saturation were consistently identified in the salt solution and distilled water circumstances, respectively. The results show that both the relationships of the montmorillonite void ratio versus the swelling pressure and the dry density versus the swelling pressure are the straight lines and parallel to the condition of distilled water circumstance in the double logarithmic coordinates when the concentration of TDS is 12.3 g/l, and the swelling pressure in the logarithm changes linearly with the concentration of TDS. As a result, a method to predict the swelling pressure and deformation is given from the dry density of the buffer materials and the ion concentration of salt solution.