Precisely laying up to 1,000 metres of underground cable without having to dig a continuous trench: that is the aim of the innovative E-Power Pipe® tunnel boring technique which Amprion has developed together with boring specialists Herrenknecht and RWTH Aachen University, funded by the Federal Ministry for Economic Affairs and Energy.
- The Cutterhead has a diameter of 505 millimetres.
- The cone crusher crushes the bored material for subsequent removal.
- The control cylinder holds the machine precisely on the preset course.
- The navigation system is connected to a control computer on the surface. It is based on a magnetic field which is generated by a power cable situated in the ground.
- The bypass is part of the supply and slurry circuits. By switching over the fluid circulation can be maintained during a machine stop without having to flush out the processed area.
- The hydraulic unit provides up to 22 kW for the propulsion of the cutter head.
- The jacking pipes are successively inserted into the launch shaft, thus forming a closed pipe string. They simultaneously provide the power supply for the machine and allow the removal of the soil via hydraulic circulation.
- The jet pump generates a vacuum in the jet nozzle whereby the removed soil and the slurry can be flushed out through the suction pipe.
Successful pilot project:
in spring 2017 Amprion and Herrenknecht tested the new technique under real conditions for the first time in the town of Borken in North Rhine-Westphalia. Three parallel, 300-metre-long borings with a depth of 2.5 metres were made. Under the local conditions, best performances of up to 126 metres of tunnelling per day on the pilot boring demonstrated the effectiveness of this tunnelling technique. “Using E-Power Pipe® we hope to gain benefits during the execution of future cable-laying projects, for example when we have to tunnel beneath roads, railway lines or areas with delicate surfaces”, notes Dr Jan Bruggmann, head of Amprion’s Cable Technology and Construction Department. However, further tests will be needed. Only after gathering sufficient experience will Amprion add this new technique to its tool kit.