不連続性岩盤における突発湧水を対象とした地質調査の価値に関する一考察

A Consideration on the value on geological investigation focusing on water inrush in discontinuous rock masses from viewpoints of construction contract

大津 宏康*; 有薗 大樹*; 三枝 博光

Otsu, Hiroyasu*; Arizono, Hiroki*; Saegusa, Hiromitsu

岐阜県瑞浪市において日本原子力研究開発機構が建設を進めている瑞浪超深地層研究所における立坑掘削工事を事例として取り上げ、不連続性岩盤サイトにおける突発湧水を対象とした地質調査データを蓄積することの価値に関して考察を加える。なお、突発湧水が発生する危険性の検討においては、不連続亀裂ネットワークモデルを用いた地下水流動解析を実施した。

This paper focused on the value on geological investigation from a viewpoint of construction contract, focusing on the risk caused by water inrush into underground structures such as tunnels/shafts constructed in discontinuous rock masses. In detail, water inrush evaluation using Discrete Fracture Network Model has been conducted focusing on the Mizunami Underground Research Laboratory construction project carried out by the Japan Atomic Energy Agency. Finally, it is pointed out that the accumulation of geological information help to mitigate losses due to geotechnical risk, and the contract of construction projects including unforeseeable geological condition should be regarded as incomplete contract, considering necessity of negotiation.