December saw Herrenknecht hand over an E-Power Pipe machine to Heitkamp Construction Swiss GmbH for use – among other projects – on its section of Germany’s SuedLink Project, a new underground cable connection to transport wind power from northern Germany to Bavaria and Baden-Württemberg. At a length of 700km, SuedLink will be the largest transmission cable in the network and the longest underground power cable in the world. With E-Power Pipe®, cable protection pipes can be installed quickly and safely underground over long distances of more than 1km without the need for trenches.
In Germany alone, the upcoming network expansion projects will require around 4,500 so-called crossings. Crossings are the most challenging sections of underground high-voltage cable routes. Trenchless technologies are essential for overcoming geographical obstacles such as rivers, swamps and wetlands, for protecting nature reserves and recreational areas, groundwater zones, the landscape and valuable agricultural land, or for passing under transport infrastructure, supply and disposal lines or buildings.
The innovative Herrenknecht E-Power Pipe method is used for trenchless installation of protective pipes at shallow depths. Both pressure-resistant and non-pressure resistant product pipes can be laid quickly, safely and precisely over long distances of up to 2km, says Herrenknecht. The two-phase process integrates aspects of proven horizontal directional drilling (HDD) and pipe jacking (microtunnelling).
The centerpiece is the fully remote-controlled AVNS350XB jacking machine, which is designed for lengths of over 1,000m with a drilling diameter of 505mm. The machine can follow the planned route with a high degree of precision, safely passing under existing infrastructure such as pipelines, roads, railways or smaller bodies of water. Individual drillings can be realized at a small distance of only 1–2m and thus several lines can be laid in parallel.
The tunnelling machine is equipped with a jet pump and an integrated hydraulic unit. To date, the cramped space conditions limited the technical possibilities for the removal of material over longer sections using conventional methods and thus also restricted the possible jacking length. By using the jet pump to remove the excavated material, jacking distances up to 10 times longer can be realized at high speeds in the small diameter range.
A thrust unit is installed at the starting point, and the thrust force of this unit is used to push the jacking pipes and jacking machine along the predetermined alignment towards the target point. The borehole remains permanently and securely mechanically supported by the machine and the jacking pipes. After breaking through at the target point, the jacking machine is disconnected from the jacking pipes. The prefabricated cable protection pipe is then connected to the jacking pipes still in the borehole and pulled back through the launch shaft using the thrust unit, thus completing the deployment of the E-Power Pipe. The underground cables can then be pulled in by specialized companies.
“The planned bores must be very precise, with some very low and some very high overburden. The longest planned route is about 1,600m long and under difficult conditions,” says Philipp Kohlschreiber, CEO of HEITKAMP Construction Swiss GmbH. ”Herrenknecht is currently the only provider of a suitable technology with EPower Pipe and is the undisputed market leader in the field of underground drilling technology with extensive expertise.”
Maximilian Bischoff, Product Manager E-Power Pipe at Herrenknecht, explains: “EPower Pipe combines the advantages of microtunneling and HDD, thus complementing our product portfolio. In the context of current grid expansion projects, we are seeing increased interest in this innovative technology, which has already proven itself in various projects. E-Power Pipe can particularly demonstrate its strengths in long sections, near-surface bore profiles and narrow pipe corridors.”
Heitkamp Construction Swiss will be laying cable protection pipes for the extra-high voltage direct current transmission line in various construction lots of SuedLink, each in a series of sections, starting in April 2025. Heitkamp Construction Swiss has founded a new subsidiary in Germany, Heitkamp Energy Infra GmbH, for this purpose.
MACHINE DATA E-POWER PIPE®
› Machine type: AVNS350XB
› Boring diameter: 505mm
› Max. torque: 10kN
› Diameter of protective pipe: approx. ID250mm to ID400mm (ID710mm with reamer machine)
› Installation length: > 1,000m
› Installation depth: 1.5m to 10m
› Distance between lines: 1m to 2m
Herrenknecht
Pioneering Underground Technologies - Herrenknecht AG is the technology and market leader in mechanized tunnelling. As the only company worldwide, Herrenknecht delivers cutting-edge tunnel boring machines for all ground conditions and in all diameters - ranging from 0.10 to 19 meters.
More Information | info@herrenknecht.com | +49 7824 3020
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