[1C13-18] Bentonite chemistry

5:00 PM - 5:15 PM JST(8:00 AM - 8:15 AM UTC)

[1C16] Effects of Material Type on Compaction and Swelling Characteristics of Bentonite-Soil Mixtures

*Kinji Yoshimoto¹, Hirohito Kikuchi¹, Ryo Yasuda¹, Takayuki Abe¹, Hikaru Oguri², Ayumu Ito², Masakazu Chijimatsu² (1. RWMC, 2. HAZAMA ANDO)

Keywords:

Geological Disposal,Backfill material,Bentonite sand mixture,Compaction properties,Swelling properties

Bentonite-soil mixtures using locally excavated materials are being considered as backfill materials for tunnels in geological disposal facilities. Compaction tests (JIS A 1210) and swelling pressure tests were conducted on mixtures combining six types of bentonite from three domestic deposits and four types of domestic aggregates (simulated excavated soils) to compare their effects on compaction and swelling characteristics. The influence of bentonite type was greater than that of aggregate type on both compaction and swelling characteristics. Bentonite type was suggested to affect compaction characteristics through differences in exchangeable cation composition (leached cation content). Aggregate type was suggested to affect compaction characteristics through differences in particle size and pore size distributions. Swelling characteristics were suggested to be influenced by montmorillonite content and exchangeable cation composition of the bentonite.