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Hermann-Hesse-Bahn Althengstett Tunnel Forst

Slope Stability - Hermann-Hesse-Bahn Althengstett Tunnel Forst 2019

Protective mesh at the tunnel portal, with bat culverts

Slope Stability - Hermann-Hesse-Bahn Althengstett Tunnel Forst 2019

TECCO® G65/3 covering the heavily weathered retaining wall

Slope Stability - Hermann-Hesse-Bahn Althengstett Tunnel Forst 2019

Stabilized natural stone retaining wall up to 6 meters high

Slope Stability - Hermann-Hesse-Bahn Althengstett Tunnel Forst 2019

Protected tunnel portal with a cutout for the stairs

Slope Stability - Hermann-Hesse-Bahn Althengstett Tunnel Forst 2019

Overall view of the stabilized wall

 
 

Year of installation

2019

Initial situation

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.

Geology

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).

Description

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.  

Country/Region

Germany

Other participating companies

Protected object

Railway

Corrosion protection

GEOBRUGG SUPERCOATING

Your local contact

Kevin Coyle
 

Kevin Coyle

Regional Manager Northeast

Natural Hazards
Hydraulic Engineering
Geobrugg North America, LLC,3 Beaudet Terr,CT 06237 Columbia / United States Regional Manager Northeast

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Saleh Feidi
 

Saleh Feidi

Natural Hazards
Hydraulic Engineering
Geobrugg North America, LLC,8921 Emperor Ave.,91775 San Gabriel, California / United States

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John Kalejta
 

John Kalejta

Natural Hazards
Hydraulic Engineering
Geobrugg North America, LLC,KS 67226 Wichita / United States

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Bob Lyne
 

Bob Lyne

Natural Hazards
Hydraulic Engineering
Geobrugg North America, LLC,8004 Windspray Drive,NC 27358 Summerfield / United States

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Pierce Runnels, Civil Engineer
   

Pierce Runnels

General Manager Geobrugg North America

Natural Hazards
Geobrugg North America, LLC,22 Centro Algodones , Civil Engineer General Manager Geobrugg North America

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Tim Shevlin
 

Tim Shevlin

Natural Hazards
Geobrugg North America, LLC,OR 97302 Salem / United States

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