Ruth Falls Hydro Plant, Geotechnical Design, Nova Scotia Power
Meco was retained by NSPI to conduct an investigation of the slope failure for the Ruth Falls Power Canal embankment.
This project demonstrates Meco’s ability and knowledge in earth embankment design as well as geotechnical investigation and dam remediation expertise.
Meco was responsible for the geotechnical investigate as well as the remedial design and analysis to ensure the earth embankment slope stability is safe. Meco was also involved in the construction management and supervision during the re-construction of the failed slope.
The main components of the project deliverables were:
- Emergency response with on-site guidance for temporary stabilization pending further investigation.
- Geotechnical Investigation and development of design parameters for slope stability.
- Prepare an options analysis of remedial solutions for stabilization of the slope and the toe of the embankment.
- Prepare contract documents for preferred remedial solution, including tender and capital cost estimates.
- On site resident engineering services to verify construction was completed as per the design and tender documents.
Risk Assessment of Snare Forks Dykes Foundation Failure, Northwest Territories Power Corp (NTPC)
Meco was retained by Northwest Territories Power Corporation (NTPC) to assess the risk of vertical and lateral deformation of saddle dykes at the Snare Forks Hydroelectric Project.
The dykes are constructed on a glacial lacustrine foundation with discontinuous permafrost. The dykes have experienced differential settlement and the grade is re-established bi-annually, or tri-annually.
The NTPC conducted a subsurface investigation in 2014 that identified continuous ice lenses for areas of the dam foundation. Meco conducted a risk assessment of failure modes related to internal erosion, vertical deformation and lateral spreading by developing a thermal and geotechnical model of the structure, using data from the 2014 investigation, with the objective of developing remedial options.
The objective is to deploy Best Applicable Practices (BAP) and Best Available Technologies (BAT) within the framework outlined in Canadian Standards Association Technical Guide Document Plus 4011-10, “Infrastructure in permafrost: A guideline for climate change adaptation” (CSA 2010).
The project deliverables included:
- A review of the risk methodology in CSA 4011-10 and applied it to foundation design for dams and use of BAP.
- Prepare foundation models for static stability, thermal stability and seepage analysis (internal stability).
- Comment on foundation failure mode analysis for shear and settlement failure using a risk approach to model varying parameters.
- Comment on adaptations and remedial options to provide long term solutions to the potential loss of dam integrity.