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Technology Spotlight: Retractable Head System by Herrenknecht Technologies

Retractable Technology in Direct Drilling

Kramer is an industry leader in providing the cutting-edge Retractable Head System by Herrenknecht Technologies


Over the years, there have been many technological innovations within the direct pipe and microtunneling industry. In 2008, underground technologies pioneer, Herrenknecht, first released their Retractable Technology. Since then, they have further developed this technology to enhance the Direct Pipe industry.

Advantages of Retractable Technology

The Herrenknecht retractable technology allows for direct drilling where no reception shaft is possible. Though blind hole drilling is required, this technology allows for minimum loss of material and equipment. The main advantages of retractable microtunneling are:

  • Site installation can happen in the same place
  • It’s an easy combination of technologies
  • Features a stabilizing steel sleeve
  • Serves as a drilling solution for unstable ground conditions
  • It widens the application of horizontal directional drilling (HDD)
  • Based on well-proofed technology
  • Up to 230 meters (755 feet) of 72 inch (6 feet) casing installed
  • Up to angles of 16.5 degrees

Did you know? Kramer Direct is the only company in North America offering this innovative technology in the direct pipe industry?

Case Study of Retractable Head System

Advantages of Retractable Technology

Project: Bellegarde, France

Overview: Combination of Retractable Technology and HDD. This project used the Herrenknecht Retractable Head System to bring in steel pipe casing for the HDD-Machine through difficult ground conditions.

Project Details:

  • Pipe Data: ID 1190 OD 1220
    • I=12m Steel Pipe
    • ID 3000 AD 3540
  • Tunnel Length: 200m (total)
  • Drive Length: 2 x 100m
  • Geology: Gravel driving into soft rock

Problem: The site was located near the surface where HDD was not possible. The upper level geology was composed of gravel with deeper layers being soft rock. There was a danger of bore hole collapse if traditional methods were pursued.

Advantages of Retractable Technology
Solution: By using the retractable head technology, contractors were able to get the casing tunnel down to the rock in order to move ahead with the horizontal drilling. This is a great example of how retractable technology innovation can further direct pipe projects in circumstances where ground conditions may not be favorable.

Do you have a project where retractable technology could help? Contact Kramer today to learn more about this service and how Kramer can help your direct pipe project.