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

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

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.