Remedial Works to Avoid Flooding in the Biassa Tunnel Rail Connection from La Spezia to Genova

摘要

The Biassa tunnel was subject to severe flooding inside during rainy seasons and train traffic suffered unwanted stops due to submerged rails. The tunnel drainage system was poor and to solve the problem, a new water collecting system was designed by taking into consideration the total estimated amount of water for each portion of the tunnel. Building new drainage required an important excavation below the tunnel with technical problems of tunnel lining and rock stability and technological problems of cutting 1.5-1.7 m thickness of medium to hard rock at the bottom of the tunnel for an 830 m long alleyway. The new large culvert has hold under the weight of the ballast, the rails and the train's weight or that of a heavy cement mixer truck.