Geosynthetics in the renewal of East Railway Line

Abstract

Geosynthetics have been widely used in various geotechnical engineering applications to enhance the strength of geosystems, as well as the fact that they are economical and relatively easy to install. Separation, filtration, drainage, reinforcement and stabilization can be referred as the main functions of the geosynthetics. Regarding the reinforcement function, literature review shows that these materials can reduce the settlement and degradation of ballast. Placing geosynthetics under the ballast confines the aggregates via interlock or frictional resistance among ballast particles which then stiffen the surrounding aggregates and increase the shearing resistance of the composite system. This paper aims to present a case study where a geotextile was used for improving the subgrade bearing capacity and, therefore, reduce the settlements. The case study concerns a railway section between Elvas and Caia (border with Spain), about 11 km long. It is located at East Railway Line, a 140 km long railway line that connects Abrantes to Caia, serving as an alternative to the Center - North corridor with regard to the transport of goods. This paper describes the design, construction and installation issues related with the geotextile used.