ABSTRACT
The Botlek Railway tunnel (construction completed in 2001) near Rotterdam has a bored length of approximately 1800 meters. To receive the TBM a construction pit, the receiving shaft, has been built. Underwater concrete was placed to seal the bottom of the construction pit. This concrete slab was only temporary, the sole function is to keep the water out. Normally, plain mass concrete, without reinforcement is used for underwater concrete.
