Floor Subsidence and Renovation
The two adjacent tunnel tubes are located on the railway line Immensee - Arth-Goldau approx. 2 km from Goldau. The mountain-side tunnel tube (L = 202 m) was commissioned in 1882. The valley-side tube (L = 196 m) was opened in 1904 when the line was extended to have double lanes.
The tunnel renewal is designed for an intervention-free period of 50 years.
The following had to be investigated in particular:
• Repair of the tunnel lining and masonry walls
• Securing of the unclad rock surfaces (tunnel / preliminary cut)
• Compliant rail gauges, safety margins and contact wire height
• Functionality of the drainage system
• Substructure refurbishment / formation level protection, particularly repair of local problem areas (floor subsidence)
• Compliant safety provisions (safety recesses)
Project period: 2009 - 2014
Services: Preliminary design, construction permission design, design, tendering, detailed design, implementation, commissioning and conclusion