Factors affecting erosion in unpaved roads

Abstract

More than 90% of the road network in developing countries is unpaved and comprises of either gravel or earth roads. Such roads are prone to erosion leading to the formation of potholes, rills and gullies. Many studies have been undertaken on soil erosion, but only a few are focussed on earth roads. A systematic analysis of research on erosion of soils in earth roads was undertaken to draw out lessons that can be learnt. 564 studies were assessed. Of these only 85 were relevant to earth roads. Most significant erosion driver was rain. In addition to rainfall duration and intensity, findings were that the key factors that affected soil erosion in earth roads were soil type, clay content, soil plasticity, particle size distribution and degree of the surface layer compaction as well as traffic loading and speed.