Membrane underneath the tunnel entrance

To create enough space for the construction of a bus traffic lane, the existing underpass at Doornboslaan had to be extended. This underpass, whose approaches were equipped with one of the first membrane constructions in the 1960s, has been constructed in the new approaches in the same manner. Van Werven Projecten BV carried out all the earthwork, diving work, and underwater concrete on behalf of Colijn Aannemingsbedrijf.

Following the specifications in the tender, Genap applied two membrane constructions beneath the groundwater level for the approaches to the railway underpass. To realize this membrane construction, the sheet piles were protected with a plastic facing wall, and the entire excavation was covered with a non-woven protective fleece.

In the Doornboslaan project, a total of more than 8,500 square meters of Aquatex 1.0 mm PVC membrane and 17,000 square meters of protective fleece weighing 1000 grams per square meter were applied.