Case Study | Ooashigawa,
Kurokawa and Nanma in Japan

Glued Tunnel Seals with a Hydrophilic Round Cord
for the Omoigawa tunnel construction
at the NANMA Dam in Japan

In recent years, Typhoon No. 6 in 2002, Typhoon No. 15 in 2011, and heavy rains in Kanto and Tohoku regions in 2015 have caused damage such as house flooding in Shikawa. In order to manage the water flow more efficiently, the river arms of the Shikawa River will be connected by the new Nanma Dam.

It is expected that after the dam is in service, future flood damage will decrease significantly for the river basins of Nanma, Shikawa and Tone.

The challenge with this project

The three branches of the Shikawa River were connected by two water tunnels to ensure an efficient flow of water into the Nanma Dam. Due to the local conditions, the tunnels were of different lengths and both the diameter and the segments used per ring varied. The resulting complexity of this project with over 50 different frame types, as well as the high requirements for the tightness tests with over 80 bar, represent a challenge for our SEALABLE development and technology team that has not been comparable up to now.

Solution and benefits

Our individual planning and development of the required profiles and frames, tailored to the customer and his requirements, enables the realization of such complex projects. With our modern, digitally supported technology, we can record the test process digitally, safely and completely traceable over long period of time, even with high pressure tests. The customer was given the opportunity to follow the 72h water tightness test via video conference at any time.