Identification And Mitigation Of Rockfall Risk Zones

Abstract

Rockfall cases are a natural and dynamic geologic process, commonly occur within mountainous areas near by the cliffs undercut by human for developing building or highway infrastructures. These paper objectives were to; (i) identification of slope surface parameters and simulating of rockfall trajectory, (ii) identification of rockfall risk zones, and (iii) mitigation of the rockfall risk zones. Manmade slope in the quarry at the Kloch, Austria was chosen as the case study in this paper. Seven Kloch slope surface parameters were identified, including; dynamic and static friction angles, normal and tangential damping, rolling resistance, amplitude of roughness, and frequency of roughness. Based on the simulation results, it was identified that the rocfall would yield the kinetic energy of 230 kJ, and the bouncing height was 0.5 m. This paper also identified the distance of rock blocks run-out on the flat ground near the slope toe (rockfall risk zones). The rockfall zones were then divided into 3 areas, e.i ; red zone, yellow zone, and green zone or safe area. The distance of red zone was 5.0-12.5 m from the x axis of the slope, yellow one was 12.5-17.5 m, and green one was > 17.5 m. Hence, in order to protect the red and yellow zones from the rockfall risks, it is recommended to construct a barrier located at a distance of 7.0 m form the x axis of the slope, with a minimum height of 1.0 m. The barrier type was proposed as a retaining wall (with a capacity to restrain the rockfall kinetic energy up to 500 kJ).