In the 1960s the A2 to the south of Lucerne was one of the first sections of motorway to open in Switzerland. In the mid-90s the refurbishment of this section started including the "sinking" of two stretches of the route into cut & cover tunnels to improve the local environmental conditions as the motorway is in an urban area. All of this work had to be carried out with minimum interference to the traffic, as the route forms a crucial link in the country's motorway route through the Gotthard Tunnel between Germany in the north and Italy in the south. Details are given of the development of the designs for the ventilation systems in the 1.0 and 1.6 km long twin tube tunnels through the life of the project including the impacts of the recent major changes to the ventilation requirements for Swiss tunnels. The impact of the ongoing reductions in vehicle exhaust emissions and the need for portal exhaust air extraction systems are described together with the design of the system that has been installed. The piecemeal construction of the tunnels means that measures have had to be provided to ensure adequate ventilation during all the different phases of each tunnel's construction and these are also described.
展开▼
