Slope Protection Works for Rockfall Prevention in NH-22
NH–22 connects the states of Punjab, Haryana, and Himachal Pradesh. In this road, Zirakpur to Parwanoo stretch (length 17.5 km) has now been four-laned. A part of this four lane road has been constructed along new alignment, which is in hilly terrain involving extensive slope cutting up to 25 m height. Geologically, this area comes under Siwaliks. The rocks along new alignment of this road comprise mainly of shale, slate, sand stone, conglomerate and to small extent quartzite. These rocks in general are high to moderately fractured and weathered. Prominent weathering can be observed in shale, slates and sand stone, due to which suitable slope protection measures are required to prevent occurrence of landslide/ rockfall. At the request of project authorities, CRRI undertook a study to evaluate and advise regarding rockfall protection measures to be adopted at critical locations in this stretch. This paper provides highlights of the study at two locations investigated.