This paper proposes a preliminary highway alignment optimization model incorporating slope disaster risk management. Previous researches in highwayalignment optimization have not considered detailed slope instability condition. Various types of natural disaster including landslide, slope failure, flood, earthquake etc are very common in the Himalayan regions becauseof rugged topography and fragile geology. Construction of highway in the Himalayan regions disturbs naturally formed slope and consequences instability on the slope. An inclusive slope failure susceptibility map has been prepared by considering various types of landslide controlling factors including lithology, slope, aspect, land use, drainage density, stream drop, distance to stream and distance to lineament. In addition to slope failuresusceptibility layer, land acquisition cost, slope, landuse and unit costof earthwork excavation are considered while optimizing highway alignment. The whole process is performed in Geographic Information System (GIS) environment. A case study is carried out to investigate the influence of theslope failure susceptibility condition in alignment optimization. Preliminary alignments are searched in cost-weighted distance raster that has been created with and without consideration of slope failure susceptibility condition. The influence of slope failure susceptibility condition is noticed distinctly both with respect to location and length of alignment. Alignments obtained from preliminary optimization are compared with previously proposed alignments, and newly optimized alignments fairly verify the previous studies. Being a preliminary optimization, this study could not consider all cost functions which is the main limitation of this study, and will be considered definitively in future work.
Abstract