Permeability measurement for macro-fractured granite using water including clay

微視的亀裂を含む花崗岩を対象とした粘土を含む水を用いた透水試験

奈良 禎太*; 加藤 昌治*; 佐藤 努*; 河野 勝宣*; 佐藤 稔紀  

Nara, Yoshitaka*; Kato, Masaji*; Sato, Tsutomu*; Kono, Masanori*; Sato, Toshinori

地下を利用する様々なプロジェクトにおいて、長期的な地下水流動を評価することは重要である。長期的には花崗岩中の亀裂は鉱物の充填によって水みちが変化する。通常、岩石を対象とした室内試験では蒸留水を使用するが、実際の岩盤中では地下水に粘土鉱物が含まれる。そのような状態を模擬した透水試験を実施し、粘土鉱物の蓄積により透水性が低下する結果を得た。

It is important to understand the long-term migration of radionuclides considering carious rock engineering projects such as the geological disposal of radioactive wastes. The network of fractures and pores in a rock mass can play important roles as the pathway of the fluid flow of rock. Usually groundwater contains fine-grained minerals such as clays. It is probable that the accumulation of the fine-grained minerals occurs in a fracture if the groundwater flows in a fracture in a rock. In this study, we have conducted the permeability measurement using water including clays. Specifically, we used a macro-fractured granite as a rock sample, and investigated the change of the permeability under the flow of the water including clays. It was shown that the hydraulic conductivity decreased with elapsed time.