Client: Canadian National Railway
On November 25, 2012 a 53,000 m3 rockslide buried the Canadian National Railway (CNR) track at Mile 109.4, Ashcroft Subdivision, near Boston Bar, causing a 4-day service disruption on Canadian National’s main east-west railway connection. The rock landslide resulted in the collapse of a 21 m-long concrete rock shed originally designed to protect the railway from debris raveling out of a gully above the track. The landslide rupture surface is composed of vertical release fractures and exposed day-lighting discontinuities. A number of rock and debris landslide hazard types are identified in the post-landslide slope. The variety of magnitudes, frequencies, and seasonal occurrences estimated for these hazards posed a significant short and long term risk management challenge for construction of the track protection structure.
KCB designed an 80 m-long rock shed for CN Rail. KCB’s modular rock shed design allows for construction under railway traffic. Our five-phase methodology included:
- Characterization of rock slope hazards using LiDAR and field mapping
- Dynamic rock fall and stability analyses for conceptual design
- Detailed structural design of rock shed
- Preparing tender package and providing field services for installation of rock fall catchnet to protect work area
- QA / QC field services during construction.