膨润土-砂混合型缓冲／回填材料液塑限试验

为研究掺砂率对高庙子膨润土一砂混合型缓冲／回填材料液塑限的影响，利用液塑限联合测定仪进行了试验研究，并运用最小二乘法对混合物液塑限试验数据进行了分析。试验结果表明膨润土一砂混合物的可塑性、液塑限值和塑性指数均随掺砂率的增大而降低。对试验结果进行分析，得到了考虑掺砂率影响的混合物液塑限经验公式。混合物的液塑限并不是随掺砂率增大成比例降低，而是液限的实测值小于理论值，塑限的实测值大于理论值。得到的不同掺砂率的膨润土一砂混合型缓冲／回填材料液塑限试验数据可为高放废物深地质处置库建设提供科学依据。

Study on Liquid and Plastic Limit of Bentonite-sand Mixtures as Buffer/Backfilling Materials

To study the influence of different sand mix ratios on the liquid and plastic limit of Gaomiaozi bentonitesand mix ture used as buffer/backfilling materials, experiments are performed by macrofunction tester, and the test data is analyzed using least square method. Experimental results show that the plasticity of bentonitesand mixture decreases with increasing sand mix ra tios, and the boundaries of water content of liquid and plastic limit and plasticity index decreases linearly with increasing sand mix ratios. Empirical formulas for liquid and plastic limit of bentonitesand mixed buffer/backfill materials under conditions of different sanding, mining ratios are proposed by fitting the experimental data. Liquid and plastic limit of the mixture don＇t decrease propor tionally with the increase of sand mix ratios, but the measured value of the liquid limit is less than the theoretical one, the plastic limit being the opposite. The obtained test data of liquid and plastic limit of bentonitesand mixed buffer/backfill materials, with dif ferent sand mix ratios would provide good reference for the construction of repository for deep geological disposal of high level radio active waste.