The goal of this project is to secure the reinforced concrete bottom and wall slabs of the incoming water channel and also to prevent their final breakage and flushing away by water flow.
The project owner is Russian State energy company «Rushydro» and it is projected by OAO “Lenhydroproject” engineering company from St. Petersburg in cooperation with Robit Rocktools. From Robit´s side the project was supported by Mr. Kari Juntunen and Mr. Juha Sorjonen. The project also included underwater drilling which was made during the operation of hydro power plant.
The project included the following stages:
- diving operations in the depth of 8-9 m with water flow rate of 0,5 – 1,0 m/s
- drilling through 1,7 – 1,95 m reinforced concrete bottom slabs using 1 m diam. diamond bit
- removal of 1 m diam. pieces of reinforced concrete slab from the bottom
- construction of 720 mm pipe pile wall (height 11,5 m) on the river bottom through the drill hole in reinforced concrete slab
- concreting of the seam between the reinforced concrete slab and pipe pile wall
- underwater concreting and installation of the pipe pile wall on the whole length of channel
After the operations above the complete pipe pile wall is installed according to the cross section of the incoming water channel of hydro power plant. This construction is used to prevent the breakage and flushing away of reinforced concrete bottom slabs what has already taken place during the last 20 years of operation.
Time of the project is 2 years but due to the working schedule of the power plant surface and underwater operations can be commenced only in July – September.
The installation of pipe pile wall was started in July 2013 by contracting company “OOO SU-299” from St. Petersburg. Till the end of September 15 piles were drilled and 20 m of pipe pile wall was installed. The method has proved to be successful and economical in the extremely hard working conditions of Yakutia.
From “OOO SU-299” company the project was managed by Mr. Vitali Korshunov, Project Manager and Mr. Vladimir Klimov, Development Director.
The following machinery was used in the project:
- “BRAUN” diamond drilling equipment and tools
- “ROBIT ROCKTOOLS” drilling technology and tools, Wing Bit DTH SF 720/10 N180
- “COMACCIO” DTH drilling rig
- “ROBIT” 18” DTH hammer
- 200 t and 500 t barges, floating crane 5 t , a towing vessel