Protective duct section in liquid soil

A redundant power line from the north substation on the EVO premises in Offenbach to a new data centre was laid in a joint venture with LUPP Netzbau on behalf of ENO Energienetze Offenbach.

Empty pipe bundles were laid along a route of around 800 m, into which control cables and 20 kV and 1 kV cables needed to be pulled.

The cable sections were to be backfilled with the excavated material, which was to be screened and filled along the route area using a liquid soil system and mixing vehicles set up on site.

Liquid soil was specifically chosen because its properties can be defined. It was not only important that the liquid soil could be installed effectively in the empty pipe bundles section. It was also essential for pipes to be embedded homogeneously without any air pockets and, in particular, for thermal conductivity (λ > 2) to be determined during liquid soil production by adding special components (compound).

The pipe bundles needed to be secured by installing buoyancy protection devices to prevent the cable ducts from floating up while liquid soil was being laid.

To ensure watertight pipe sections, the cable ducts were pressed downwards individually before and after the liquid soil was installed.