Geosynthetic Reinforcement for Unpaved Roads – Recent Experience

Modern geosynthetic materials, including geotextiles and geogrids, are often used to generate savings in materials and time on construction projects. Geosynthetics are used as reinforcement and separation membranes for unpaved roads that are supported by low strength or unsuitable subgrades. When geosynthetics are used, unsuitable subgrades can be left in place and reduced thicknesses of road base are required. This paper reviews the design methods currently used to build geosynthetic reinforced unpaved roads and documents the validation of these design approaches. A number of recent case histories of projects in the UK and Ireland are outlined, showing the use of geotextiles and geogrids to reinforce unpaved roads founded on peat, alluvial soils, and low strength glacial tills. The cost savings achievable are commented upon and the results of performance monitoring over time are presented. The overall aim of the paper is to show how geosynthetic reinforcements can be efficiently utilised in unpaved access roads over unsuitable subgrades, leading to savings in materials, time, and reduced environmental impacts.