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DSI Austria  ›  Products  ›  Tunneling & Mining  ›  DYWI® Drill  ›  DYWI® Drill S-D Expansion Bolts Type T
DYWI® Drill Expansion Bolt Type T
DYWI® Drill Combination Rock Bolt versions MN and GT-TU
DYWI® Drill Expansion Bolt

DYWI® Drill Expansion Bolt Type T

Within the last few years, various so-called “one-step” rock bolt systems have been developed. This is a result of steadily increasing demands on rock bolting procedures in underground Mining and Tunneling and the ensuing higher demand for self-drilling rock bolts. The self-drilling rock bolt product family has now been extended by providing an expansion element for the DYWI® Drill Hollow Bar System.

The key factor for the success of this rock bolt is the combination of the longterm proven DYWI® Drill Hollow Bar with a robust and innovative expansion element. The DYWI® Drill Expansion Bolt is installed self-drilling; borehole drilling and bolt installation are accomplished in one operational step. The system’s adaptability to changing rock and ground conditions is an important feature of the DYWI® Drill Expansion Bolt.

Immediately after the self-drilling installation, an activation of the expansion element leads to immediate load-bearing capacity. The DYWI® Drill Expansion Bolt can be optionally tensioned following the fixation of plate and nut. Subsequent grouting, de-coupled from the actual installation procedure, permits further optimization of installation cycle times.

The DYWI® Drill Expansion Bolt is available in two different versions. Type M is mainly used for systematic rock bolting in underground Mining (see separate brochure). Type T is used for rock bolting in hanging wall areas and in applications that require an extension of bolts using couplings.

Fields of Application


  • Systematic rock reinforcement
  • Rock bolting in remote areas or areas of difficult access
  • Supplementary bolting
  • Utility and hanger bolts


  • Rock bolting in underground caverns
  • Face bolts
  • Driving in critical ground conditions
  • Squeezing ground

Civil Engineering

  • Rock fall and rock slide protection
  • Anchorage of avalanche barriers
  • Reinforcement of excavation pits and retaining walls

Main Advantages

  • Simultaneous drilling and installation
  • Installation using standard drilling machinery
  • Immediate load-bearing capacity after installation and activation of the expansion element
  • Reduction of cycle time due to the de-coupling of the grouting procedure from installation
  • Ability to maintain load-bearing capacity even when undergoing large deformations
  • Tough system components
  • Safe, easy, and reproducible installation procedure
  • Improved drilling accuracy thanks to the directional guidance of the self-drilling expansion element
  • Trouble-free application in unstable borehole conditions
  • Easy extension using couplings
  • Design and diameter of the expansion element can be adjusted to suit different and varying ground conditions
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