The second Heinenoord Tunnel in the south of Rotterdam is a pilot project in order to gain experience in mechanized tunnelling in soft ground with high groundwater level – the typical geological formation encountered in the western Netherlands. The twin-tube tunnel is planned for slow traffic providing separate lanes for pedestrians, cyclists and agricultural vehicles. The objective is to relieve the existing first Heinenoord Tunnel beneath the Oude Maas River ("Old River Maas") between Rotterdam and the Europoort area.
A Herrenknecht Mixshield, 8.55 meters in diameter, excavated the tunnel. This machine type is specially designed for tunnelling in heterogeneous geological conditions. To stabilize the ground during excavation, a bentonite-water mixture is used for tunnel face support and the tunnel is lined with segment rings parallel to excavation. Only one year after the installation of the first segment, the first section was successfully completed. Breakthrough along the second section occured in July 1998. The new tunnel is opened to traffic on September 16, 1999.