Development of coupled THMC numerical simulator and it application to geological disposal

2022 Fiscal Year Final Research Report

• Project/Area Number: 19H02237
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 22030:Geotechnical engineering-related
• Research Institution: Ehime University
• Principal Investigator: YASUHARA HIDEAKI 愛媛大学, 理工学研究科(工学系), 教授 (70432797)
• Co-Investigator(Kenkyū-buntansha): 岸田 潔 京都大学, 工学研究科, 教授 (20243066) ; 木下 尚樹 愛媛大学, 理工学研究科(工学系), 准教授 (30263958) ; 青柳 和平 国立研究開発法人日本原子力研究開発機構, 核燃料・バックエンド研究開発部門 幌延深地層研究センター, 研究職 (40636841)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: 熱・水・応力・化学連成 / 連成数値シミュレータ / き裂性岩盤 透水・物質移行挙動 / 地層処分事業

Outline of Final Research Achievements

Roughness stiffness tests and flow-through experiments were conducted under high temperature, high pressure, and saline water conditions to simulate an underground environment in granite with a single fracture. Roughness stiffness tests were conducted to improve the interlocking of the rock samples, and flow-through experiments were conducted to evaluate the effect of simulated seawater under high temperature conditions on the permeability properties of the granite fracture. ICP emission spectroscopic analysis, fracture surface profiling, and scanning electron microscopy were also conducted to investigate the factors that cause changes in permeability over time. In addition, a coupled simulator was developed to describe the permeability change of cracks in a coupled thermal, hydraulic, stress, and chemical field, and the validity and usefulness of the simulator were verified by reproducing and analyzing laboratory tests.

Free Research Field

岩盤工学

Academic Significance and Societal Importance of the Research Achievements

本研究では、地層処分時に想定される温度、応力、地下水環境を模擬した条件で室内試験を実施し、亀裂性岩盤の透水特性の長期変性メカニズムを明らかにした。また、変性メカニズムを記述する現象論モデルを実装した熱・水・応力・化学・連成解析シミュレータを開発した。本研究成果は、地層処分技術の信頼性向上のために必須事項と設定されている課題に真正面から取り組んでおり学術的意義は高い。