Method for Balancing Cut-Fill and Minimizing the Amount of Earthwork in the Geometric Design of Highways

Abstract

In highway projects, economic considerations are as important as other design controls and elements of design. As a result, the highway designer should consider cut and fill balance along with minimizing earthwork which may significantly decrease construction costs. In practice, one way to reduce the amount of earthwork is to set the grade line as closely as possible to the ground line while also considering cut and fill balance. However, this practice may be misleading since balancing is achieved along the centerline of the road. In reality, the centerline ground elevation rarely represents the whole cross section in terms of cut and fill balancing. Especially in mountainous terrain, transverse changes in ground elevation with respect to the centerline elevation of cross section are abrupt. The aim of this paper is to propose a method that considers a hypothetical “weighted ground elevation” representing the average of transverse changes in the ground elevation rather than the elevation at the centerline. Consequently, conforming the grade line to the weighted ground line (integration of the weighted ground elevations along the centerline) would give balanced cut and fill and lesser amount of earthwork, resulting in a much more cost effective result.