ABSTRACT
Indian transportation network in mountainous terrain and hilly areas suffer due to frequent failure of slope and occurrence of landslide predominantly during the periods of heavy rainfall. This occurs due to disturbance of equilibrium between resisting force and driving. Such failures result in ground movement in the form of slides, creeps, falls, or flows. Therefore, slope stability is a very important part of design of transportation systems, which depends upon ground soil conditions, slope geometry characteristics and pore-water pressure, The construction activities for transportation systems in hilly areas, which include proper topographical survey, fixing of alignment, geotechnical investigation, formation of layout, laying of different subgrade layers with other associated structures, are also quite challenging and risky. Hence, absence of appropriate men-materialsmachineries, poor contract documentation, unrealistic assumption, and improper design in DPR stage leads to instability and failure during construction. The present paper focusses on slope failure of transportation system in hilly areas and its possible remedial measures. A parametric study has been conducted for different soil parameters and water table conditions with a common slope geometry to understand the slope stability criteria. In the present research, an attempt has been made to develop correlation between results with considered parameters, such as, factor of safety against slope failure. Different finite element models have been developed for three separate ground conditions, which are loose to medium sand, medium dense sand and very dense sand layer followed by soft rock layer. It has been found that with the improvement of ground condition from loose to medium sand to medium dense sand and from medium dense to very dense sand factor of safety increases appreciably with reduction of surface settlement by 7-12% and 20-21% respectively. The present case study may help practising engineers to design transportation systems under similar situations.
