Finite Element Study of Unreinforced and Reinforced Unpaved Roads Subjected to Repetitive Vehicular Loading

An unpaved road system is frequently subjected to distresses arising especially from rutting. This phenomenon is mostly imbibed by the repeated vehicular loading acting on the aggregate layer. Traditional design undrained analysis of unpaved road design leads to overestimated aggregate thickness, which has an eventual toll on the project cost. Hence, it becomes imperative to comprehend the behaviour of the unpaved road system subjected to repetitive vehicular loading and its consequent effects on rutting. This paper reports, the detailed outcome of Finite Element (FE) based analyses of unreinforced unpaved road system comprising a soil subgrade represented by generalized shear strength parameters. The aggregate layer is subjected to repetitive vehicular loading arising from different axle loads, and their influence on the rutting behaviour is illustrated. Further, to counteract rutting originating from higher axle loading, a planar geotextile with different stiffnesses is introduced at the aggregate-subgrade interface. The study successfully shows that even a single layer of high tensile strength geotextile can completely arrest the accumulation of deformation beyond certain number of loading cycles.