Fabric for Reinforcement and Separation in Unpaved Roads

摘要

Researchers performed laboratory experiments on soil-fabric-aggregate systems to211u001eevaluate the effect of a geotextile on unpaved road performance. Direct shear 211u001etests performed on gravel indicated a 42 degree friction angle. Similar tests 211u001eperformed on soil-fabric-aggregate systems resulted in an interface friction 211u001evalue for the nonwoven geotextile system similar to that of the gravel alone. The 211u001eslit film and heavy weight woven systems generated friction angles about 20 211u001epercent lower. Observations of model tests showed that in terms of rut depths, 211u001ethe nonwoven performed better than the slit film woven geotextile for all gravel 211u001ethicknesses, most likely because of the nonwoven's higher frictional 211u001echaracteristics. The rut diameters for the slit film and nonwoven reinforced 211u001esystems tended to be larger than those observed for the unreinforced systems 211u001eindicating an increased load-spread angle through the gravel. Based on rutting 211u001ealone, the unreinforced model with 200 mm (8 in.) gravel was equivalent to that 211u001eof the slit film in reinforced model with 150 mm (6 in.) gravel and the nonwoven 211u001emodel with 100 mm (4 in.) gravel. A so-called bearing capacity factor for the 211u001eunreinforced models was approximately 50 percent less than the nonwoven 211u001ereinforced models, in reasonable agreement with theory.