ABSTRACT
In this paper we present issues related to the performance of immersed tube tunnels in the Netherlands. A range of issues are experienced for the ageing structures including long-term settlement at tunnel joints and consequent leakage. Because of the age of these structures some important aspects are often unknown thus creating uncertainty regarding remediation measures. Having discussed general issues the paper presents a case study of the Kil Tunnel which has experienced relatively large settlements over the past 40 years. In this case a lack of geotechnical engineering information for the soils below the tunnel was identified. A geophysical survey was undertaken and this provided ley insights into the ground conditions at the tunnel site.
