Horizontal corridor optimization of highway using GIS & CFSC method in mountainous areas

Abstract

The highway planning process needs a complete assessment of existing conditions in the geographic region that may affect the construction of a new highway, and it must satisfy a set of design and cost constraints that hardly can be reached without using Geographic Information Systems (GIS). Many essential criteria related to construction, maintenance, and structural subjects cannot be considered during the horizontal corridor determination step.In this research, we studied the effect of road slope stability in determining the horizontal highway corridor at the preliminary design phase. The soil properties are predicted using California Bearing Ratio (CBR) test, and critical failure state charts (CFSCs) are proposed to evaluate the safe height of the slope and, consequently, evaluate the requirement of supporting systems like concrete retaining wall.The predicted retaining walls' locations are determined by applying GIS and Least-Cost Path Analysis (LCPA) method. Finally, a mathematical model for finding the optimum corridor between two points is implemented, and according to the adopted cost classification, the cost of the retaining wall can be classified as low.