ABSTRACT
The Rhaetian Railways AG (RhB) manages about 384km of rail network in the Canton Graubünden in Switzerland. Due to the mountainous topography, many civil engineering structures had to be built along the network, 115 of which are tunnels realized between 1901 and 1914. 75 tunnels with an overall length of 26km have damages due to water income, therefore representing a serviceability issue. The challenge and the purpose of the RhB is the rehabilitation of these tunnels in the next 50 years defining an expected service life of 100 years. To reach this purpose, a standard method was studied called “Standard Tunnel Construction Method”, which allows to replace the masonry ring with a close ring of prefabricated concrete elements, to widen the cross-section, to excavate the invert and place prefabricated concrete slabs completed with poured concrete. Application of this construction method to the tunnel Mistail will hereby shown and described.
