Interpretation of hydrogeological characteristics based on data from long-term cross-hole pumping test

長期揚水試験結果に基づく水理地質構造の解釈

尾上 博則 ; 竹内 竜史  ; 三枝 博光; 大丸 修二; 狩野 智之

Onoe, Hironori; Takeuchi, Ryuji; Saegusa, Hiromitsu; Daimaru, Shuji; Karino, Tomoyuki

Groundwater flow conditions in crystalline rock are usually heterogeneous due to presence and characteristics of faults. Uncertainty of the hydraulic heterogeneity is influenced to safety assessment for geological disposal of high-level radioactive wastes. Therefore, evaluation of hydraulic and solute transport properties of the faults are a high priority investigation issue. A long-term cross-hole pumping test was carried out to evaluate hydraulic properties of a major fault in study area. In the test, completely different pressure responses were measured in monitoring boreholes on opposite sides of the fault. As a result, adequacy of groundwater flow conceptual model taking into account a hydraulic compartment structure was confirmed, and additional hydraulic compartment structure was inferred to occur. This study indicates long-term cross-hole pumping test are an effective method for hydrogeological characterization of heterogeneous fractured rock.