ABSTRACT
The Miyama Tunnel is a 768m double-track tunnel located on the Hokuriku Shinkansen Line (between Kanazawa and Tsuruga) and in the city of Tsuruga in Fukui Prefecture. The site has many active faults which could lead to sudden groundwater seepage. The tunnel is also near the Nakaikemi Wetlands, which are registered under the Ramsar Convention. This made the prevention of any lowering of the groundwater level a concern. Five measures were taken, to reduce any negative effects on the wetlands due to excavation. First, the route was realigned, based on the suggestion by experts. Second, watertight lining was applied to keep the groundwater level stable. Third, various measures were taken to shorten the time of construction. Fourth, extensive and continuous survey were conducted. Lastly, a water level recovery plan was created. No major effects on the wetlands have been observed but monitoring surveys are conducted to help maintain the wetlands.
