NAUE protects groundwater
Location of work/project:
Germany – Wendlingen-Ulm – Deutsche Bahn
For a new high-speed rail line, NAUE meets special requirements
Part of the future high-speed railway line Wendlingen-Ulm, Germany, runs over karstic
ground. These soils require extra groundwater protection measures. NAUE geomembranes and protective nonwoven geotextiles were selected for the project to meet the railway construction’s stringent engineering requirements – including numerous elaborate connections.
One of the challenges has been constructing atop karst in what is known as the “Alb plateau”. The inconsistency of the karst allows water to seep quickly into the ground, often to a significant depth. Project officials required a design according to the German Water Protection Act. This meant that the track needed a sealed system in these zones. The cut slopes and embankments needed to be sealed from below to at least 2m above the top of the rail with clay. It was therefore necessary to have a separate seal at the edge between the slab track and the lateral drainage.
Carbofol® HDPE 406 2.0 F/F DB geomembranes were installed along with Secutex® R 901 DB nonwoven geotextiles above and below the barrier layer. The geomembrane featured a texturing on both sides to increase frictional characteristics and intimate contact at the interface with the protective nonwoven geotextile. This design guarded against mechanical damage to the geomembrane, even with horizontal forces from railway activity transferring into the ground.
The geomembrane layer was installed at least 0.5m under the base course on the rail side and was integrated into the drainage ditch on the field side. A particular challenge during the installation was the need to incorporate more than 500 penetrations. This required many separate connections with the posts of the overhead line. Roughly 70,000m² of Carbofol® and around 140,000m² of Secutex® were installed.