Water Stopping in a large and deep excavation
Client: Geotech, an Acciona Company
Location: Baldivis, WA
Sector: Water Infrastructure
The problem
Our client was involved in the construction of a water pumping station for the Water Corporation using secant piling. The secant piles, at depth, were misaligned allowing ground water and sand to flood into the excavation. This was significantly delaying the project’s construction program.
A Secant Piled Wall is a retaining wall constructed for ground retention prior to excavation. The wall is formed by constructing alternating primary (female) and secondary (male) piles where the secondary piles partially cut into either side of the primary piles to form a continuous impervious structure.
The solution
The excavation was 20m deep in clean sand with a high water table. Water stopping with high ground water pressures and on such a large scale is often akin to an artform rather than a science that requires on-the-hop experimentation with various materials until you find the optimum combination. And it requires persistence. Just when you think you are on top of the leak, it will surprise you with a new challenge.
To solve this problem Ironstone Civil’ team drew on all their water stopping experience and product knowledge. The crew drilled between and through the secant piles to inject water stopping materials whilst toiling to keep sand out of the hole. A combination of polyurethanes, acrylates and rapid set repair mortars was used.
Pleasingly, persistence paid off and we were able to stop the water leaks to enable our client to recommence their construction works. Safety and quality assurance was paramount to this project success.
“From the early engagement stages, Ironstone Civil showed a high level of expertise in their field coupled with a fantastic approach to resolving the difficult remediation works on site. Their proactiveness and positivity continued throughout the delivery phase and when new challenges arose the team were quick to provide solutions that benefitted the nature of the work, the project program and the budget of the client. I can’t speak highly enough of the staff at Ironstone Civil, they are a pleasure to work with and this is reflected in the work they deliver which is safe, efficient and to a high standard. If you ever require specialist remediation of structures, then I would highly recommend engaging Ironstone Civil.”
Josh Winnicott – Geotech, Senior Project Engineer