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回填材料是高放废物地质处置库多重屏障系统的重要组成部分,以蒙脱石为主要成分的膨润土是较理想的回填材料,研究膨润土的非饱和渗透特性,对于回填材料选材和处置库安全性评价具有重要意义。文章通过室内试验开展柯尔碱膨润土的土水特性研究,用压力膜仪实测不同干密度柯尔碱膨润土的土水特征曲线,根据柔性壁渗透仪测得的饱和导水率数据,采用Van Genuchten(1980)预测模型分别计算得到每种干密度膨润土在不同含水量及基质吸力条件下的非饱和导水率,建立了非饱和导水率与含水量、基质吸力的相关关系,对比分析干密度对曲线的影响。结果表明,干密度对柯尔碱膨润土的土水特征曲线有着明显的影响,在初始含水量相同的情况下,干密度较大的膨润土脱水速率比干密度较小的膨润土脱水速率慢,表现出较高的持水性能。柯尔碱膨润土的非饱和导水率随含水量减小和基质吸力增大皆呈非线性降低,干密度越小,非饱和导水率越大。
Backfill material is an important part of the multi-barrier system of geological disposal repository for HLW. Bentonite with montmorillonite as the main component is the ideal backfill material for studying the unsaturated permeation characteristics of bentonite and the safety of material selection and disposal of backfill materials Evaluation is of great significance. In this paper, the soil-water characteristics of Kerr alkali bentonite were studied through laboratory tests. The soil water characteristic curve of different dry density Kerr alkali bentonites was measured by pressure-gauge instrument. According to the saturated hydraulic conductivity data measured by flexible wall infiltrometer, Van Genuchten (1980) prediction model, the unsaturated hydraulic conductivity of each dry density bentonite under different water content and matrix suction was calculated respectively. The correlation between unsaturated hydraulic conductivity and water content and matrix suction was established. The dry density Effect on the curve. The results showed that the dry density had a significant effect on the soil-water characteristic curve of Kor base bentonite. Under the same initial water content, the dehydration rate of bentonite with higher dry density was slower than that of bentonite with smaller dry density, High water holding capacity. The unsaturated hydraulic conductivity of Coke bentonite decreases nonlinearly with the decrease of water content and the increase of substrate suction. The smaller the dry density is, the larger the unsaturated hydraulic conductivity is.