myGeobrugg
2019
The Black Forest Railway has been recently reactivated between the cities of Weil der Stadt and Calw. The Hermann Hesse Railway has now once again connected Calw to the Stuttgart region. A particular challenge was the 1200 meter long and up to 36-meter deep cutting between Althengstett and Calw, which dates back to 1872.
Its embankments were originally supported at the foot by up to 6 meter high natural stone walls, which in some areas are heavily weathered and are exposed to further erosion. In addition to the stability and economic efficiency, high demands on nature conservation had to be taken into account during the rehabilitation. The entire cutting area is located in the Black Forest Nature Park.
Middle Triassic strata of the Lower Muschelkalk
The region contains the Freudenstadt Formation, which is up to 55 meters thick and consists of clayey, sometimes also sandy dolomitic marls with intercalated harder dolomite layers.
The formation is underlain by an approximately three-meter red clay formation of the Upper Buntsandstein. The layer boundary is recognizable in the terrain by its colors gray-beige (Muschelkalk) to dark red (Buntsandstein).
The stabilization of the embankment and the protective wall was accomplished with 3,200 m² of high tensile TECCO® G65/3 mesh. An additional 320 m² of stabilization was installed on the right side of the tunnel portal. The access stairs, as well as bat culverts, were also stabilized. The high tensile mesh was selected due to its strength properties, corrosion resistance, low visibility, uniform strength for anchor placement and speed of installation.
The water flow conditions and the current sintering in the retaining wall are now largely preserved by the mesh. The broken-out wall stones were replaced, prior to meshing and thus an attractive surface has been created. The historic site is now protected by the TECCO® system.
Germany
Railway
GEOBRUGG SUPERCOATING