Improving railway drainage with multi-linear geocomposites FIGURE 6 Drainage geocomposite installation on slope PROJECT HIGHLIGHTS RAILWAY DRAINAGE OF CUT SECTIONS OWNER RFF/SNCF LOCATION France GENERAL CONTRACTOR Roland/Eiffage Group ENGINEERS SNCF Reseau Ingenierie et Projets GEOSYNTHETIC PRODUCT DRAINTUBE FTF2 D25 GEOSYNTHETIC MANUFACTURER Afitexinov Geosynthetics 24 Geosynthetics | June July 2022 it requires more than 300 dump trucks to cover the same area with a 1 foot (300 mm) thick gravel drainage layer. Case study: Railway drainage of cut sections Cut sections involve massive, tall slopes designed to maintain stability and avoid landslides. In case of the presence of groundwater, drainage masks using granular material require large amounts of materials. The use of a multi-linear drainage geocomposite for subsurface drainage reduces that need for copious granular material. The drainage geocomposite is unrolled directly on the subgrade with the mini-pipes in the direction of the slope (Figure 6). It is anchored on top of the slope and connected to a French drain at the toe. The backfill is then placed on top of the product from the bottom to the top (Figures 7 and 8). The drainage geocomposite does not provide additional strength resistance for the stability of the slope. But due to the nonwoven needlepunched geotextile layers of the product, the geocomposite/ soil interface angle is approximately the same as the internal friction angle of the soil in contact.