Case Study of Landslide in NH –13 at Kethikal Near Mangalore – India

The disastrous slope failure occurred at the Kethikal hill, in the outskirts of Mangalore city in NH 13, India, during the month of June 1998 soon after the heavy and continuous monsoon rains. Many closely built dwelling houses at the top of hill are damaged and the traffic along the road is also diverted for some duration. Typical stratified slope with three layers is considered for the stability analysis and the general computer program is developed in C language for optimization of factor of safety. The factor of safety is calculated using Janbu’s generalized procedure of slices and Davidon-Fletcher-Powel (DFP) technique for optimization. The road is acting as a berm in Kethikal slope. The program gives factor of safety and the co ordinates of critical slip surface. The program is modified to take the effect of tension crack and the effect of berm. The automated stability analysis program gave least value of factor of safety in base failure with tension crack and a berm. The obtained result matches with the field observation. Kethikal landslide is due to the development of high pore pressure in soil