Development of a simplified design approach for shallow ballasted track forms with geocells reinforced sub-ballast

Abstract

ABSTRACT With increasing demands for higher axle loads and line speeds, designers are left with no choice but to significantly increase track bed design thickness to accommodate the new operating conditions. In recent years, the use of geosynthetic materials has become more common in railway construction to reduce construction depth. Geosynthetic materials such as geocells have shown promising potentials to achieve this. However, there is no universally agreed method to design track bed with geocells. Therefore, the aim of this paper is to quantify the reinforcing effect of geocells on the track bed via means of laboratory testing and then incorporate the findings with existing track bed design methods to propose a simplified approach to design track bed with geocells. The research is further supported by case studies from the UK railways and found that the use of geocells can significantly reduce track bed thickness, resulting in significant cost savings.