ABSTRACT
In this study, the required cross-section size of railway tunnels from the technical viewpoint of civil- and railway engineering was investigated and compared to the cross-section sizes of the Norwegian technical regulations on railway tunnels. The reduction potential of the cross- sections was investigated with regards to its effect on the CO2-emissions and cost in the construction phase of railway tunnel projects. Cross-section measurements of two tunnels on Gardermoen-line was obtained and further demonstrated and analyzed to investigate the reduction potential in relation to today’s technical standards and newer tunnel projects in development. A simplified computational model for cost and CO2-emission from the building phase was established to investigate the effect of cross-section reduction on the cost and CO2- emissions, where the analyzed data from Gardermoen-tunnels were used as input parameters. It was found that the areas for evacuation, fixed installations and the track construction was the parts within the cross sections with the highest reduction potential, because of the possibility of combining the evacuation- and installation area and using ballast-less track. The reduction potential was found to be in the magnitude of 10m2. Giving a reduction in construction cost of about 4000 kr/m, a reduction of CO2-emissions of about 500 kg CO2 pr unit length and a reduction in the cost related to the CO2-emissions of 900 kr pr unit length. Through the study it was found that today’s design method is in small degree suitable for optimization of tunnel cross section size. Because of the great reduction potential found in the project, in addition to several factors related to the complexity of railway tunnels which makes the design process challenging.
