Sealing of the Wien river flood-control wall by means of injections

Injections have been used to seal the flood-control wall that separates the Wien river bed from the tracks of underground line U4. A total length of wall of 5 300 metres are in need of repair. The repair area has been divided into segments of 50 m wall length each, i.e., 106 segments. The injection works for filling voids in the wall have been carried out in two stages. In 2009, Sections C1 to C6 were repaired and injected. Before this, binding criteria for injections and injection targets had to be set, which have to be inspected and regularly monitored by means of permeability tests and core sample analysis, among other methods.