Tunnelling experiences on using conveyor belt for mucking at the world-longest and deepest subsea road tunnel
The Solbakk twin tube tunnel is currently the longest and deepest subsea road tunnel under excavation. The tunnel is excavated from Strand, and from Hundvåg, north of Stavanger, with a total length of 14.3 km and a maximum depth of 292 m. Marti IAV Solbakk DA has the 7.9 km tunnelling contract from Strand towards Stavanger. The excavation method is conventional drill and blast, with use of conveyor belt for the transportation of the excavated rock material. This paper aims to cover experiences from the Solbakk project on utilizing a conveyor belt for muck transportation. The paper describes the traditional mucking with trucks and the conveyor belt methods and their differences, highlights the logistic advantages and disadvantages and the resulting total project benefits, analyses the energy balance, the greenhouse gas emissions and the health & safety aspects. Additionally, it compares the results of the analysis of different projects with the Solbakk tunnel.