[1C05-07] Technology development

11:00 AM - 11:15 AM JST(2:00 AM - 2:15 AM UTC)

[1C05] Evaluation of Material Segregation Behavior of Backfill Material Using Screw Feeder Method

*Takayuki Abe¹, Ryosuke Takamatsu¹, Hisayuki Watanabe², Motoki Moriiwa², Takuo Mori², Daisuke Tsukamoto² (1. Radioactive Waste Management Funding and Research Center, 2. Obayashi Corporation)

Keywords:

Geological disposal,Backfill,Screw feeder method,Segregation

This study evaluated the material segregation behavior of backfill material composed of bentonite and crushed sand, focusing on the screw feeder method for tunnel backfilling in geological disposal. Screw backfilling tests were conducted with bentonite ratios of 15%, 30%, 50%, and 75%, and segregation tendencies were examined through particle size distribution tests of samples from upper and lower portions after backfilling. At 15%, coarse particles accumulated at the bottom due to slope sliding, while at 50% and 75%, fine particles accumulated due to mass collapse. At 30%, both sliding and collapse were minimal, showing the least segregation among the four mixtures. The 30% bentonite mixture, containing more fine particles than the Fuller curve, was identified as the most appropriate composition for suppressing material segregation.