Use of nonwoven geotextile in the
rehabilitation of a railway line
Location of work/project:
Geo & Tex 2000
Mud pumping in railway subgrade under the repeated loadings generated by trains can seriously affect the lifetime of a railway. In the rehabilitation of railway lines, the installation of a separation and filtration nonwoven geotextile should be always considered as efficacious solution to prevent pumping phenomenon, enabling the infrastructure to last for the designed service time.
After the end of Yugoslav Wars, the Countries of former Yugoslavia have begun to rehabilitate the infrastructure network, investing also in a new efficient railway system integrated in the Pan-European Corridors.
Of all the projects related to the modernization of the Balkan railway network, one of the most important has been the Vinkovci-Tovarnik line in Croatia, at the Serbian border, with a section of about 35 km to be reconstructed.
The project has indicated a large use of a nonwoven geotextile and of a geogrid in the construction of the track substructure. The primary role of geotextile has been to separate the soils out of which the railway embankment was constructed from the sub-layer, in order to keep the characteristics of both materials unchanged. The technical specifications for the geotextile have considered:
Type, mechanical characteristics and water permeability of the materials of the embankment
Size of granular materials of the new sub-layer
Compressibility module value at the level of bedding formation
Resistance of the geotextile to all kind of stresses during the installation phase and during all its service life
Properties required for the non woven geotextile:
Wide-width Tensile strength MD/CMD: ≥ 20/20 kN/m (EN ISO 10319)
Elongation at maximum load MD/CMD: ≥ 30/30%
Static puncture resistance: ≥ 3200 N (EN ISO 12236)
Permeability coefficient normal to the plane ≥ 1 x 10-3 m/s (EN ISO 11058)
Characteristic opening size: 6 micron ≤ O90 ≥ 200 micron (EN ISO 12956)
Resistance to UV radiation
Resistance to chemical and microbiological degradation
Installed material was a high tenacity staple fibre polypropylene non woven geotextile, UV stabilized, type GEO PP 4 NG (280 g/2m).
Quantity installed was 300.000 sqm, on a rail section of 50 km.