Improved Performance of Subballast Stabilized Using Geocell for High Speed Train

Rapid urbanization and growing industrial demand in many developing countries has led to frequent congestion of the transport infrastructure. Therefore, the expansion of high-speed rail (HSR) networks is crucial to meet this growing demand. Nevertheless, applying high cyclic stress causes significant lateral spreading and in turn excessive settlements of the track substructure. This problem becomes more crucial when the subballast layer is constructed using locally available poor quality granular material in order to keep the construction costs to minimum. The use of planar form of geosynthetics (geogrid, geotextile, geocomposite) to improve the performance of rail track is well established. Large-scale laboratory and full scale field studies conducted in the past at the Center for Geomechanics and Railway Engineering (CGRE) of the University of Wollongong, NSW, Australia, have shown that geogrids and geocomposites of appropriate technical specifications can effectively reduce track settlement. Recent studies have shown that cellular confinement, known as geocell mattress, can offer more confinement than planar geogrid for the infill material. By employing geocell as reinforcement in subballast layer, tensile strength mobilized as an additional confinement and arrests lateral spreading of infill material and help to maintain track geometry.