The White River Dams hydro project comprised of building two dam liners. This hydro project is located 50km south of the town of White River in Northern Ontario, Canada. A joint venture between Regional Power and Pic Mobert First Nation, development started in August 2013 and continued through all of 2016. There are two separate hydro generation locations Gitchi Animki Bezhig (Upper) and Gitchi Animki Niizh (Lower) positioned 10km from each other. They are both considered ‘greenfield’ projects.
The dam liner was constructed to be a free-standing low-permeability wall, built on a concrete foundation tied to the riverbed, held inside a plinth of compacted rock and gravel. Obstacles with coating and sealing to achieve the required low permeability excluded conventional steel sheet piles in favor of composite. Our composite sheet pile solution was also favorable when correlated on cost over the expected 50 – 70 year lifespan of the dam liner project.
With hydraulic head of 14 meters in the Upper Dam, regulation 35-foot composite sheet piles were used, amalgamated with hand-applied hydrophilic sealant, to accomplish a permeability of no less than 10-11.
The Lower Dam, with a White River composite installation hydraulic head of 21 meters, required a dam liner 72-foot in height. With the largest composite sheet available being 52 feet in length, Wolf Hammer designed, tested and built an H-Clip to join sheets vertically, extending the wall to the required height.
To reinforce the large sheets while being installed our project lead designed a tailored framing solution of soldier piles and whalers.
The stainless steel prototype H-Clip (patent pending) took six weeks for development and testing. The testing apparatus granted the H-Clip between two sections of 4’ composite sheet pile to place a force downwards to create 2" of deflection while underwater, with 20lbs psi. MWH Global Engineering Vancouver office authorized the testing criteria and findings.
We were able to test their sealing techniques in the joints of the sheets to allow for 70’ of head pressure on the upstream side of the Dam wall. This testing was done with pressure of up to 110lbs psi with no leakage.
The use of FRP sheet piling as the core of a hydropower dam is relatively unique. This paper focuses on the use of the sheet pile core in the dam design and includes a summary of the testing and analyses performed to evaluate the FRP sheet pile core material, a review of the methods adopted for construction, the lessons learned during the construction of the dams, and presents a summary of the instrumentation installed at both dams. This paper is intended to serve as a reference for those considering the use of FRP sheet piling in a similar application.