Investigation of geogrid reinforcement in unpaved road applications

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Geogrid materials' use in road projects is becoming an important geotechnical practice. Placed between the subgrade and base course, or within the base course, the geogrid improves the performance of unpaved roads. Currently, the design of geogrid reinforced unpaved roads is based on an empirical method, which doesn't allow efficient utilization of modern stronger geogrids. The main objectives of this project are to understand the reinforcing mechanism of geogrids and optimize the location of the geogrid layer and quantify its reinforcing effect. This will involve monitoring the performance of geogrid layers with different strength chracteristics and placed at different locations in a field study.The testing program will be carried out at the Environmental Site of Western University (ESWU), London. The ESWU has an unpaved road (entrance), which experiences significant rut due to the heavy traffic and will be considered here as the test road. It will be subdivided into 5 segments. Four segments will be reinforced with geogrid material (manufactured by Terrafix, i.e. TBX 1500, TBX2000, TBX2500 and TBX3000) and one segment will be used as base line (control). Each segment will be subdivided into two sections. In one section, the geogrid will be placed at 200 mm below the ground surface. In the second section, the geogrid will be placed at 400 mm below the ground surface. The global geogrid strain will be measured by using four Position Sensors. A set of earth pressure transducers will be used to monitor the stress state at different locations in the base and the subgrade. In addition, all geogrid layers will be strain gauged at various locations to monitor the stress distribution in the geogrid. In addition, the road surface will be surveyed regularly to establish the change in elevation (rut) after each hundred load cycles