Facing the supreme discipline:
Underwater cutting at the Flumenthal power plant in Switzerland
At the Flumenthal power plant in the municipality of Riedholz in Switzerland, a completely new fish ladder is currently being built in the form of a bypass channel – the ideal construction site for Tyrolit diamond tools and machines.
After the construction of the Flumenthal power plant 50 years ago, fish in the Aare were able to overcome the difference in height between the upper and lower water via a fish pass. However, this no longer meets today’s fish migration requirements, which is why Alpiq Hydro Aare AG commissioned a completely new fish ladder in the form of a 480-meter-long bypass channel. Within the framework of this project, the old concrete bank wall below the power plant’s estuary had to be removed and replaced by a new one.
For this job, three companies were involved: Bohrex AG as the executing company, Tyrolit for consulting and supporting the project, as well as the diving company TAF Taucharbeiten AG. In a first step, various holes were drilled with Tyrolit core drill bits in order to feed the saw wire for the vertical cuts and to secure and recover the dismantling elements. After several vertical cuts, the major challenge, however, was the final 25-metre horizontal cut, which could not be carried out with standard machines due to the required machine power and the enormous cutting length under water. The project team therefore successfully used a special construction in the form of two connected Tyrolit SB wire saws.
No project without its challenges
The heavily reinforced concrete and the loose material on the one hand, as well as the strong water flow caused by heavy rainfalls on the other, made the work a challenge for all parties involved. The fact that a large part of the dismantling work was carried out under water also made this project very special. Safety was also a top priority during the cutting work: The operators were secured by a safety line at all times and the cut elements were additionally secured to prevent them from being carried away by the current.
Safety was a top priority in this project. The users were secured at all times with a safety line.
A diving team monitored and supported the dismantling work under water and was always in contact with the team onshore.
In order to overcome the underwater cutting challenge, the team came up with a special construction of two connected SB wire saws by Tyrolit.
Illustration of the horizontal cutting works.