Study of technique for ensuring long-term integrity of rock mass and and environmental protection by mineral precipitation

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K04596
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 22030:Geotechnical engineering-related
• Research Institution: Kyoto University
• Principal Investigator: Nara Yoshitaka 京都大学, 工学研究科, 准教授 (00466442)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 岩石 / セメント系材料 / き裂 / 空隙 / 鉱物析出 / 透水係数

Outline of Final Research Achievements

To ensure the safety of a rock mass and structures, the tensile stress should be avoided. However, if the crack sealing and healing happen, the long-term integrity of a rock mass and structures can be ensured. In this stydy, it was planned to create the technique to ensure the mechanical integrity of rock and cementitious material using aqueous environmental condition where the concentration of ions are high. Especially, using rock and cementitious material, measurement of permeability was conducted to investigate the change of the hydraulic conductivity by the crack closure. It was clarified that the crack closure occurred by the mineral precipitation on the cracks and pores, which resulted in the decrease of the permeability.

Free Research Field

岩盤工学

Academic Significance and Societal Importance of the Research Achievements

岩石やセメント系材料内部のき裂や空隙が修復されていることから，本研究において示した現象は，材料の強靭化にもつながるものと考えられる。特に，カルシウムイオンや炭酸イオンが豊富に存在する水中環境下でカルシウム化合物が析出しき裂閉塞が起こることを見出しているため，カルシウムイオンが豊富な水中環境は，岩盤や構造物の長期安定性の確保に大きく貢献でき，放射性廃棄物処分のような岩盤工学プロジェクトの安全性確保に好都合であると考えられる。