Rock mass movements across bedding in Kananaskis Country, Alberta

Abstract

Rock mass movements in sedimentary rocks across bedding in Kananaskis Country, Alberta, are controlled by discontinuity orientations and topography. When bedding planes dip at less than 50°, small rock masses can slide along strike joints or fall and slope angles remain unchanged. When bedding surfaces dip at 65–70°, large rock masses topple and then slide or simply slide along sheeting joints or combinations of bedding surfaces and strike joints to reduce slope gradients. Block toppling and sliding models of large slope movements in highly jointed rock masses indicate that toppling mode is more critical than the sliding mode. A natural example, the 6 × 106 m3 Elk Ridge landslide, shows toppling from bedding planes followed by sliding can be catastrophic. Key words : topple, slide, landslide, rock, Rockies.