The tunnel under the Martwa Wisła river is part of an infrastructural project “Trasa Słowackiego”, which included several investment packages. Trasa Słowackiego is a road link between Rębiechowo airport and the eastern part of the Port of Gdańsk, where the road connects to Trasa Sucharskiego, forming a ring bypass around the Gdańsk centre.
Minerals DC Nowak was awarded the contract for the supply of natural marine aggregate for this project. The construction process took more than two years and used approximately 100,000 tons of marine aggregate. The marine aggregate sourced from the Baltic Sea deposit known as “Południowa Ławica Środkowa – Bałtyk Południowy” was used in cast-in-place concrete structures, especially the tunnel concrete lining, concrete piling, and sub-base layers.
The construction of the tunnel is a project of gargantuan proportions and the only of its kind in Poland to date. The 1.4 km section comprises two road tunnels running under the Martwa Wisła river with the lowest structural point nearly 35 m below terrain level. Each of the two tunnels has two lanes. The two tunnels are interconnected with seven mini emergency tunnels. The tunnels were built using a TBM (tunnel boring machine). The construction of the tunnel, plus the already completed three sections of Trasa Słowackiego, required an investment of PLN 1.420 billion, of which PLN 1.154 billion were granted by the European Union. The construction process formally began at the end of 2011, but the work started in 2012 Q1. The project was completed at the turn of 2014 and 2015.