The Use of Draintube Drainage Geocomposites Under Railway Infrastructures: Fid-Bau Portal

The Use of Draintube Drainage Geocomposites Under Railway Infrastructures

Fourmont, Stephan / Riot, Mathilde

Railway construction involves substantial earthworks (embankments and cuttings). Cuttings may reach the water table, and embankments may need preloading when on soft soils. Even during operation of the railway line, the ballast put into place under the railways undergoes densification and degradation over time which reduces the hydraulic conductivity of the material. This phenomenon may affect the durability of the structure if the ballast is not able to evacuate the water during heavy rainfall, flooding or snowmelt. Drainage systems for soil water were traditionally made with granular material layers and perforated collector pipes, one of the main reasons being the ability of that system to support heavy loads over time. As their flow capacity is not load or time-sensitive when confined in soil, drainage geocomposites with mini-pipes Draintube are often used instead of the granular drainage layers. At the different stages of the railway construction, it protects the cuttings against high water table, decreases the time for consolidation on soft soils and increases the overall drainage capacity of the system under ballast. It also allows the use of Hydraulically Bound Materials (HBMs) on top of it. This publication presents a case study for each application, along with the related laboratory study or on-site monitoring. Drainage geocomposites with mini-pipes have been successfully used for 30 years; the product is designed for each project function of the specific site conditions. It requires less machinery to install and reduces the Greenhouse Gas (GHG) emissions compared to a granular material solution.