Rockfall analysis along transportation corridors in high hill slopes

Abstract

The paper discusses the problems pertinent to rockfall activities in highly jointed rock cut slopes, excavated without detailed geotechnical and geological investigations along the right bank of river Sutlej, Luhri, Himachal Pradesh, India. The cut slopes are near vertical to sub-vertical and overhangs are ubiquitous at several locations. Initially, probable zones of slope failure were identified from field inspection and kinematic analysis. The study then uses 2D rockfall analysis for estimating loss of energy due to the impact of falling blocks on the slope face and subsequently on the road. Several parameters were also assessed from the study viz. bounce height, travel distance, kinetic energy and translational velocity. The result from rockfall analysis shows that the energy and velocity achieved by the falling blocks are considerably high, capable enough to cause severe damage. In relation to energy and velocity, bounce height achieved is not very large. Because of removal of trees from the slopes face and no measures to capture falling blocks, the problems have been aggravated and therefore, most of the rock covers very large distance to reach up to the valley crossing the roadways endangering travelers and infrastructures. Based on the results, preventive measures have been suggested to prevent future rockfall hazards.