[1C13-18] Bentonite chemistry

4:30 PM - 4:45 PM JST(7:30 AM - 7:45 AM UTC)

[1C14] Investigation of the Effects of Aggregate Particle Size Characteristics on the Development of a Hydraulic Conductivity Model for Bentonite Mixtures

*Okuto Nihei¹, Ryo Yasuda¹, Takeshi Ishiguro², Masafumi Hirata² (1. Radioactive Waste Management Funding and Research Center, 2. Maeda Corporation)

Keywords:

Intermediate-depth disposal,Bentonite mixtures,Hydraulic conductivity,Base soil particle size,Multiple regression analysis

Bentonite mixtures are considered for low-permeability layers and upper backfill zones in engineered barriers for intermediate-depth disposal. Their hydraulic conductivity depends not only on bentonite properties (e.g., swelling, mixing ratio, and compaction) but also on the particle size characteristics of the base soil. However, existing evaluation models do not adequately account for these effects.In this study, experimental data from multiple base soils were analyzed using multiple regression with water content, dry density, mean particle size, and uniformity coefficient as variables. The results show that conductivity increases with mean particle size and decreases with uniformity coefficient. These findings highlight the importance of incorporating base soil particle size into evaluation models for improved material selection and mixture design.