ABSTRACT
Objects in transport infrastructure, such as bridges, tunnels and culverts, are usually built using reinforced concrete structures. However, since the 1970s, many structures have been constructed with corrugated steel plates and surrounding backfill to form soil-steel composite structures. The paper analyses the soil-steel composite railway tunnel located in Tolpinrud, Norway. The analysed tunnel has a cross-section in the form of a pipe arch with a 7.81 m span and a 6.92 m rise. The tunnel is constructed of steel plates with a 200 mm corrugation pitch, 55 mm depth and 6.8 mm plate thickness. The depth of the soil cover over the steel shell crown varied from 1.1 to 1.6 m. The study’s main aim is to show the long-term behaviour of the soil-steel tunnel as well as earth pressure, which has been monitored for 25 years. Experimental studies of the soil-steel railway tunnel were compared with the results of finite element analyses (FEA) performed in the numerical program DIANA FEA. The numerical analysis took into account subsidence and earth pressure during the operation of the tunnel. The long-term behaviour of the soil-steel tunnel demonstrates that there are changes in earth pressure distribution and structural response over time after construction. The numerical analysis performed can be helpful in the design of new soil-steel tunnels and bridges situated on roads and railways. In addition, the study results may help assess the technical condition of the existing soil-steel composite structures.
