ABSTRACT
A comprehensive evaluation procedure for the two long tunnels through the Swiss Alps was performed based on requirements established by AlpTransit Gotthard AG and BLS AlpTransit AG. Special influences such as high geothermal heat, high pressure of mountain mass, construction, and high expectations for the service life-time – 100 years – had to be considered. Polymeric products combined to waterproofing systems (membranes: PE, PE-Cop, PVC-P, drainage materials: PE, PP, PA, PES) were tested in a 24 months program. Existing test methods were complemented, e.g. by ageing at elevated temperatures and in oxygen-enriched water at elevated temperatures, respectively, compression creep tests, behaviour under combined lateral compression and horizontal shear, and installation tests. The installation tests showed that the waterproofing membranes develop regular folds with small radii of curvature during construction. Since most products did not meet all requirements, optimised systems were re-evaluated.
