Managing rockfall risk through baseline monitoring of precursors using a terrestrial laser scanner

Abstract

Rockfalls represent significant risks to safe and efficient use of transportation corridors. In this paper, we address the management of rockfall risk through baseline remote monitoring of susceptible slopes (every 2–4 months) along a transportation corridor along the Fraser River valley in western Canada using a terrestrial laser scanner and supporting remote sensing technologies. This includes identifying potential rockfall source zones based on incipient signs of failure, tracking kinematics in three dimensions to better understand the mechanism of failure, estimating potential failure volumes based on bounding joint structure, and transmitting this information to the railway operator for an assessment of risk. We demonstrate our approach for one case along the line where we identified several potential failures ranging in volume from 48 to 4200 m3. Our projections of the location of failures were successful, in that volume projections were within 10%–55%, and the anticipated kinematics and failure mechanism were consistent with the assessment of post-failure rockfall scar geometries. Accurate volume and kinematics estimates are important for the assessment of hazard and risk as well as the planning of risk mitigation options. In general, this approach can be used to better manage risk from rockfall hazard in communities, transportation corridors, or other infrastructure.