Rhine Culvert Worms

As part of the redevelopment of the old Nibelungen Bridge at Worms it was necessary to relay the utility lines carried by it. A solution was found by undertunnelling the River Rhine with a culvert, which could accommodate the following utility lines:

1 DN 600 drinking water pipeline
420 kV medium voltage cable systems
1110 kV high tension cable system
5 protective pipes for communication cables.

The route was selected to comply with the particular aspects of influencing nature and the environment, favourable line connections with the existing network as well as the setting up of the pipe columns. After investigating the geology, which was mainly characterised by sand, gravel and silt, submissions for the tender could be invited. The project contained a special proposal, which foresaw the use of the direct pipe method for the first time. This newly developed method devised by the Herrenknecht AG and the Ingenieurbüro Dr. Kögler was selected because apart from the economic aspect, it was appealing on account of the minimal construction period, a calculable construction risk, a low negative effect on the environment and the fact that it did not hamper Rhine shipping. Towards this end a precast protective column of pipes consisting of a total of six 90 m sections was laid by trenchless means on the side of the Rhine in Hesse. The excavation was carried out using the navigable direct pipe tunnelling machine based on the water-supported face principle. The muck was carried to the separating plant via a flushing circuit and separated there. The real novelty is that the pipe thruster has the task of pushing the precast pipeline forward. The pipe column transfers the required jacking force to the head. An average thrusting force of only 80 t was measured (given a maximum 500 t force for the pipe thruster) for the jacking period of 13 days - given a total route length of 464 m. The minimum overburden along the route amounts to 3 m. The main advantage of this method was that operations could be confined to the construction site on the Hesse side of the river, where the pipe jacking installation was set up along with the pipe column laid on a raised slipway. A special laying concept was developed for installing the various utility lines. The subsequent DN 600 water pipeline in this case served as the carrier system, which had four rollers and a clamping system attached to it, which was able to hold the other utility cables. After concluding the pipe jacking operations the remaining cavity was filled with porous light concrete for positional stability and protect against corrosion.

Country: Germany
Region: Worms
Tunnel utilization: Utilities
Type of utilization: Water Pipeline, Energy and Communication Cables
Client: EWR Netz GmbH
Feasibility Study: Ingenieurgesellschaft de la Motte & Partner GmbH
Contractor: Sonntag Baugesellschaft mbH & Co. KG/Sax+Klee GmbH
Main construction method: Trenchless
Type of excavation: Shield machine (SM)/Direct-pipe?
No. of tubes: 5?
Tunnel total length: 464 m
Cross-section: 1.18 m (internal diameter), 1.22 m (48'; external diameter)
Construction start/end: autumn 2007
Opening: February 2008