日本地球惑星科学連合2018年大会

講演情報

[EJ] ポスター発表

セッション記号 S (固体地球科学) » S-CG 固体地球科学複合領域・一般

[S-CG57] 変動帯ダイナミクス

2018年5月23日(水) 15:30 〜 17:00 ポスター会場 (幕張メッセ国際展示場 7ホール)

コンビーナ:深畑 幸俊(京都大学防災研究所)、竹下 徹(北海道大学大学院理学院自然史科学専攻)、岩森 光(海洋研究開発機構・地球内部物質循環研究分野)

[SCG57-P27] Change of pore connectivity in granular materials under confining pressures

南部 美菜子1渡辺 了1、*阿部 希道1 (1.富山大学)

キーワード:空隙、連結度、粒状物質

The pore connectivity in Berea sandstone (porosity~20%) is remarkably reduced under confining pressures. Electrical conductivity in Berea sandstone decreased by 22% as the confining pressure was increased to 40 MPa, while the pore-fluid pressure was kept at atmospheric pressure (0.1 MPa). Measured volumetric strain showed that the change in porosity under the confining pressure was less than 1%. The observed relatively large decrease in conductivity requires a significant decrease in the connectivity of pores. The effective medium theory (Kirkpatrick, 1973) suggests that around 20% of conduction paths must be closed to decrease conductivity by 22%. The observation of pore structures with X-ray CT revealed that a lot of thin pores were involved in a network of pores. These thin pores are likely to close under confining pressures to reduce electrical conductivity. Compression tests on packed quartz sand also showed that a small decrease in porosity causes a relatively large decrease in conductivity.