盐溶液的渗透吸力计算方法

THE CALCULATION METHOD FOR OSMOTIC SUCTION OF SALINE SOLUTION

膨润土垫层在高放废料处置库环境中与围岩接触,力学性能会受到围岩裂隙中所含盐溶液的影响。盐溶液的渗透吸力会在膨润土上产生类似于竖向荷载作用的附加应力,量化盐溶液对膨润土力学性能的影响对评估地下处置库的安全性具有重要意义。溶液渗透吸力系数作为计算渗透吸力的关键,目前需要通过较为复杂的实验测得,对工程实际应用造成了阻碍。通过引入Debye-Hückel公式,提出含单价离子电解质、2-2型电解质及混合电解质溶液的渗透吸力系数及渗透吸力的计算方法。基于Debye-Hückel公式,分析溶剂种类和温度对渗透吸力系数的影响,结果表明:溶剂极性越大,渗透吸力系数越大;温度越高,渗透吸力系数越小。

When bentonite cushion contacts with surrounding rocks in a disposal repository of highly radioactive waste, its mechanical properties will be affected by the saline solution contained in surrounding rock cracks, and the osmotic suction of salt solution will add additional stress similar to vertical load on bentonite. Thereiore, quantiiying the effect of saline solution on the mechanical properties of bentonite is of great significance tor evaluating the saiety of underground repository. Osmotic coefficients as the key to calculate the osmotic suction are usually obtained by complex tests, which obstructs the practical engineering applications. The Debye-Htickel tormula are introduced to calculate the osmotic coefficients and osmotic suction tor monovalent ion electrolyte, 2-2 type electrolyte and mixed electrolyte solutions. The impact of various factors on solution suction coefficients, such as solvent type, solute type, solute concentration and temperature are analyzed. Then the calculation method of osmotic suctions of different solutions are obtained. Based on the Debye-Htickel tormula, the influence of solvent type and temperature on the osmotic suction coefficient is analyzed. The results show that the larger the solvent polarity, the larger the osmotic suction coefficient; the higher the temperature, the smaller the osmotic suction coefficient.