Abstract
Abstract
The Chakki Moad section of National Highway-05 (NH-05) in Solan District, Himachal Pradesh, represents one of the most landslide-prone corridors within the Lesser Himalayan region. The area experiences recurrent slope failures that significantly disrupt transportation, damage infrastructure, and threaten public safety. The present study evaluates the geological, geomorphological, structural, hydrological, and anthropogenic factors controlling slope instability in the corridor. The regional geology comprises the Subathu, Dagshai, and Kasauli Formations, while local exposures include highly weathered sandstone, siltstone, mudstone, shale, and unconsolidated colluvial deposits. Structurally, the area is influenced by the Main Boundary Thrust (MBT), Surajpur Thrust, and associated fault systems, resulting in highly fractured and sheared rock masses. Unfavourable bedding orientation, intense monsoonal precipitation, river-induced toe erosion, inadequate drainage, and extensive slope cutting associated with highway widening have collectively increased landslide susceptibility. Historical landslide records demonstrate repeated failures between 2010 and 2026, highlighting the persistent instability of the corridor. GIS-based landslide susceptibility studies classify Chakki Moad among the highest hazard zones along NH-05. The study concludes that slope instability is controlled by the combined influence of weak lithology, active tectonics, adverse geomorphology, hydrological conditions, and anthropogenic disturbances. Comprehensive slope stabilization, improved drainage systems, and continuous monitoring are recommended for long-term risk reduction.