著者

奈良 禎太 加藤 昌治 佐藤 努 河野 勝宣 佐藤 稔紀

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.138, no.4, pp.44-50, 2022-04-28 (Released:2022-04-28)

参考文献数

34

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It is important to understand the long-term migration of radionuclides when considering rock engineering projects such as the geological disposal of radioactive waste. The network of fractures and pores in a rock mass plays a major role in fluid migration as it provides a pathway for fluid flow. The geometry of a network can change due to fracture sealing by some fine-grained materials over long-term periods. Groundwater usually contains finegrained minerals such as clay minerals, and it is probable that the accumulation of such minerals occurs within a rock fracture upon groundwater flow, thereby decreasing the aperture of a fracture and the permeability. It is therefore essential to conduct permeability measurements using water that includes fine-grained minerals to understand the permeability characteristics of a rock; however, this has not been studied to date. In the present study, we use a macro-fractured granite sample to investigate the change of permeability that occurs under the flow of water that includes two different amounts of clay. Findings showed that clay accumulated in a fracture and that the permeability (hydraulic conductivity) of the granite sample decreased over time, which was greater in for the higher clay content. We concluded that the accumulation of clay minerals in the fracture decreased the permeability of the rock. Furthermore, we consider that the filling and closure of fractures in rock is possible under the flow of groundwater that includes clay minerals.

著者

櫻井 春輔 清水 則一 芥川 真一 吉田 秀典 佐藤 稔紀 山地 宏志

出版者

公益社団法人 土木学会

雑誌

土木学会論文集F (ISSN:18806074)

巻号頁・発行日

vol.62, no.4, pp.662-673, 2006 (Released:2006-12-20)

参考文献数

25

被引用文献数

1

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超大深度地下開発のアプローチとなる超大深度立坑は,その重要性を再認識されつつある.しかし,国内石炭産業の縮小に伴い,深度1,000m級の立坑はほぼ20年以上施工されていない.筆者らは超大深度立坑技術の継承と,定量的な立坑設計技術の確立を目的として,過去に施工された超大深度立坑の技術文献調査,およびかつて施工に従事された技術者からの聞き取り調査を実施し,立坑工事において発生する蓋然性の高い崩壊形態を調査した.その結果,立坑における崩壊のほとんどは高抜けと異常地圧による覆工破損の二つに分類されることが明らかとなった.さらに,その発生状況を検証したところ,この二つの現象は同じ原因により発生するものと判断された.