Comparative analysis of limit equilibrium and numerical methods for prediction of a landslide.

Landslides that occur due to the rapid motion of a rock-mass are a primary risk in mountainous terrains and are a danger to human life and civil infrastructure. The application of geotechnical engineering methodologies for remedial purposes is to assess unpredictable behavior and the stability of the slope, and for analysis and design. The aim of the study is to quantify the global factor of safety (FOS) and describe a correlative and comparative assessment of the conventional Limit Equilibrium Model as compared with the advanced Numerical Model for the rock slopes of Amiya, Nainital, Uttarakhand in India utilizing Mohr-Coulomb failure criterion. The rock-mass characteristics were determined as a result of an estimation of the physio-mechanical properties of rock and debris from collected field samples with the help of the joint weakening coefficient for limit equilibrium (LE) and the numerical solution. Global FOS estimated by means of stability analysis procedures, such as Swedish slip circle, Ordinary method of slices, Modified Bishop, Janbu method, Finite difference static analysis, Finite element static, and Finite difference dynamic analysis, was found to be 0.65, 1.34, 1.38, 1.29, 1.57, 1.144, and 0.84, respectively. The results helped to deduce that the slope remains substantially stable and failure may only occur in the case of a down slope movement of rock debris (clastic mass of rocks) with a small local/global tremor. Combination of the LE technique and numerical approach (hybrid approach) has been found to be a better method for critical slip surface and FOS determination. [ABSTRACT FROM AUTHOR]