Evaluation of Slope Stability Analysis using Kinematic and Chart Method: A Case Study

The variability and unpredictability of climatic conditions are adding to the complexity in the prediction of the natural hazards. The Himalayan region is having a very complex geological and tectonic setting. Besides, climatic conditions and geological setting of the area, human encroachment is adding to the vulnerability of mountain slopes. The landslide, particularly rockfall, became a big problem for commuters and inhabitants in the hilly region. The landslides are mostly occurring either in the summer season or in the rainy season due to the percolation of water along the jointed weathered rock mass slopes. The researchers/scientists have investigated various reasons for the slope failure using conventional methods like kinematic and limit equilibrium method or using numerical methods like finite difference method (FDM), finite element method (FEM), discrete element method (DEM). The numerical methods FEM, FDM, and DEM has wide application but these are very costly and requires high end computation system. On the other hand, the conventional methods, which were used in the present study, is economical and requires geological experiences only. In the present study, slope stability analysis was performed for roadcut slopes of National Highway -109 (NH-109) from Bhowali to Almora (53 km) in the district of Nainital and Almora, Uttarakhand, India. A total of fourteen vulnerable locations were identified and their instability was evaluated. The types of failure were determined using the kinematic method, stability and classification of the slope were examined using slope mass rating (SMR). In addition, the chart method was used to calculate the factor of safety (FoS) for only wedge type of failure. A new graph has been proposed to find out vulnerability of slope considering only field-based approach.