TITLE:
Geo-Mechanical Analysis of Landslide-Prone Road Cut Slopes along the National Highway-5, Powari to Akpa, Kinnaur District, Himachal Pradesh, North-Western Himalaya, India
AUTHORS:
Deepak, Satish Kumar, Kishor Kumar
KEYWORDS:
Landslide, RMR, SMR, Kinematic Analysis, Wedge and Planar Failure
JOURNAL NAME:
Open Journal of Geology,
Vol.16 No.9,
September
17,
2026
ABSTRACT: Landslides are one of the most damaging geological hazards in the hilly and mountainous regions of India, including IHR (Indian Himalayan Region). Most of the National or State highways in the hills are affected by landslides of various magnitudes, attributing part from natural and triggering causal factors, as well as anthropogenic reasons like unplanned excavations. The National Highway-5, which connects the rest of the country with border areas of the region, also passes through important townships including the capital city of Shimla and district Headquarters of Solan, Shimla, Rampur and Kinnaur, thereby serving the both security as well as socio-economic purposes. Though the NH-5 gets impacted from landslides, particularly during monsoon, starting from Kalka to Kaurik border area, this research mainly focuses on the slope stability evaluation on the National Highway-5 and the adjoining slopes from Powari to Akpa using Rock Mass Rating (RMR), Slope Mass Rating (SMR), and Kinematics analysis. Seven road-cut slopes were identified for a detailed study to identify the causes and types of failure. The study reveals that the slopes, which are composed of good to fair categories of rock masses, fall under the completely unstable to partially stable conditions. Out of the seven slopes, two were critically unstable, whereas four were classified as unstable and one was partially unstable with localized zones exhibiting potential instability; however, three were classified as planar, another three as wedge, and one slope exhibits compound involving both the planar and wedge conditions.