Tunnel monitoring in urban environments

Urban tunnel projects such as new metro lines face particular challenges. Shallow overburden, difficult (hydro)geological conditions and sensitive buildings in close proximity are risks that often cannot be avoided, demanding large and complex geotechnical monitoring programmes. This paper considers the current situation of tunnel monitoring in urban environments and describes two specific monitoring solutions, one for shafts and one for structures, and emphasises the importance of efficient data management with the assistance of a tunnel information system. Finally, the paper gives an overview of recent research activity and emerging sensing technologies.