Innovations and new developments

Boring-enabled steel sleeve pipe

(DMI patent no. 10 2008 005 452)

Subsidence often takes place due to ground extraction when producing boreholes for sleeve pipe injections, especially in the vicinity of groundwater and underneath buildings. DMI has developed a unique boring system for this eventuality with which it is possible to drill in the sleeve pipes directly without protective casing.

Around five to six work steps are normal for drilling procedures in accordance with the current state of the art. The DMI system requires just two work steps and it can be deployed in small spaces. The engineering office CDM Consulting Berlin evaluated the drilling procedure and injection on the basis of a test boring operation and compiled a positive report on it.

Benefit: Two work steps

Einbohrfähiges Stahlmanschettenrohr

Pipe shields with boring-enabled sleeve pipe

The current state of the art for pipe shields does not professionally allow for one-off or repeated grouting via the driven-in valves. The valves fall out during drilling in or do not close properly.

DMI has found a unique solution for this and further developed the patented DMI steel sleeve pipe for pipe shields that allow for repeated grouting.

  • Drilling in (drawing in) the pipes with drilling jumbo by excavation personnel
  • No ramps for anchor drill necessary
  • Repeated grouting possible
  • Post-grouting possible for sealing purposes, even after excavation ø 76.1 / 88.9 / 101.6 / 114
Boring-enabled sleeve pipe for pipe shield

Boring-enabled sleeve pipe for pipe shield

Ring drill bit with latched pilot bit

Ring drill bit with latched pilot bit


  • No ground extraction so lower risk of subsidence.

  • Just two work steps instead of five, which means significantly lower labour costs.

  • More precise drilling possible as a result of displacement drilling.

  • Boreholes with smaller diameters possible as the steel sleeve pipe is also used as a borehole pipe.

  • Drilling can be performed with a small device (rotary motor), which means that use in TBMs and narrow shafts or spaces is possible.

  • Simple handling during drilling in.
  • Grouting can be performed multiple times unlike with conventional pipe shield systems.

Possible uses:

  • Pipe shields
  • Elevation injections
  • Underpinning
  • Ground stabilisation