Hydrogeological conceptual model determined from baseline and construction phase groundwater pressure and surface tiltmeter data at the Mizunami Underground Research Laboratory, Japan

瑞浪超深地層研究所における地表調査段階及び施設建設段階での地下水水圧モニタリング及び傾斜計計測に基づく水理地質概念モデルの構築

竹内 真司; 竹内 竜史  ; Salden, W.*; 三枝 博光; 新井 孝志*; 松木 浩二*

Takeuchi, Shinji; Takeuchi, Ryuji; Salden, W.*; Saegusa, Hiromitsu; Arai, Takashi*; Matsuki, Koji*

瑞浪超深地層研究所計画において、研究坑道の掘削前から掘削中において計測した地下水水圧及び地表傾斜データを用いて水理地質構造の概念モデルを構築した。その結果、地表からの調査段階で2本の立坑間に予測した地下水流動に対する遮水性断層の存在を、研究坑道掘削中の上記モニタリングデータ等の解析によって確認した。

A hydrogeological conceptual model has been developed based on pressure responses observed at multilevel pressure monitoring zones in seven boreholes and surface tilt data in and around the Mizunami Underground Research Laboratory site. Pressure changes caused by some earthquakes, cross-hole hydraulic testing, and shaft excavation activities are considered. Surface tilt has been measured from the half way of the shaft excavation phase. Continuous monitoring with some numerical analysis during the shaft excavation phase show the existence of the flow barrier fault predicted from the surface-based investigation phase and hydraulic parameter around the shafts.