RIPLEY LANDSLIDE ACTIVITY
Railways contribute to economic growth and therefore require safe, reliable and secure transportation of natural resources, agricultural product, manufactured goods, and people from coast to coast. As Canada’s economy grows, an increasing volume of imports and exports is expected to be transported by rail across the country. Parts of Canada’s railway network cross terrain that is susceptible to landslide hazards. To ensure long-term public safety and security of our rail system, various tools and techniques are being developed and used by the private sector to help monitor certain areas that are prone to slope hazard issues. In particular the section of the Canadian National (CN) and Canadian Pacific (CP) railway corridor that runs through the Thompson River valley between Ashcroft and Spence’s Bridge in southern British Columbia is an area of focus. During the past few years scientists from the Geological Survey of Canada have collaborated with representatives from China, academia, Transport Canada, CP and CN Rail in a unique study to test and evaluate a suite of various tools and technology useful in monitoring landslide prone terrain.
Using various shallow geophysical techniques including electrical resistivity, seismic refraction, fixed frequency electromagnetic induction and ground penetrating radar the nature of the moving slope materials at the Ripley Landslide near Ashcroft are better understood. Short and long term monitoring of the landslide involves a suite of techniques and methods including those listed below:
- Three (3) Permanent GPS stations installed which show movement up to 55 mm/year.
- Drill holes (5) retrieved solid cores to depth of 30 m.
- Drill hole samples for textural analysis, Atterberg limits and shear strength properties.
- Nine (9) Corner reflectors installed for RADARSAT2 interferometry which shows entire slide is moving but most movement at the south end (~68 mm/year).
- ShapeAccelArray (SAA ) installed.
- Optic ground based light detection and ranging (LiDAR) system applied.
- Five (5) vibrating wire piezometers installed.
- Ground penetrating radar (GPR) shows shallow stratigraphy and shear planes.
- Seismic refraction/reflection shows broader stratigraphic relationships.
- Distributed fiber optic strain monitoring technology deployed for first time in Canada.
- More data recovery and additional technologies are planned for the future.
David Anderson – Senior Policy Advisor