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DSI USA  ›  Products  ›  Geotechnical Systems  ›  DYWI® Drill Hollow Bar System  ›  General Notes, Installation Advantages
Temporary works support using Soil Nails
Temporary works support using Soil Nails

DYWI® Drill Hollow Bar System

General Notes

The DYWI® Drill Hollow Bar System is a fully threaded steel bar which can be drilled and grouted into loose or collapsing soils without a casing. The bar features a hollow center for simultaneous drilling and grouting and a rope thread for connection to standard drill tooling. Manufactured by cold rolling heavy wall steel tubing, DYWI® Drill Hollow Bar forms a standard rope thread profile (R25 - R51, T76 has a trapezoidal thread). The rolling process refines the grain structure of the steel, increasing the yield strength and producing a durable drill rod suitable for a range of applications. DYWI® Drill Hollow Bars can be installed into a variety of different soils and ground conditions ranging from sand and gravel to inconsistent fill, boulders, rubble and weathered rock, as well as through footings and base slabs.

Soil Nails to resist subsidence
Soil Nails to resist subsidence

Installation Advantages

  • Ability to work with small drill rigs without casing in narrow spaces
  • Similar installation methods for all ground conditions
  • Simultaneous Drill and Grout Installation: Combines both operations into a single construction cycle, enabling high rates of production
  • No Casing Required: Can be installed into loose or collapsing soils without the need for a temporary casing to support the borehole
  • Rotary Percussive Drilling: Allows quick rates of installation, good directional stability and assists in the consolidation of the grout within the borehole
Simultaneous drilling and grouting
Simultaneous drilling and grouting

Wide Range of Applications

DYWI® Drill Hollow Bars are suitable for:

  • Soil Nails, Micropiles, Ground Anchors for temporary works, Rock Bolts and Spiles.

Material Characteristics

  • Fully Threaded Rod Sections: Continuous thread ensures that rods can be cut and coupled at any point.
  • Thread Profile Standard ISO rope thread (R25-R51) or trapezoidal thread (T76) produces an excellent bond between the bar and grout, and enables connection to conventional drill tooling.
  • The hollow core serves for flushing with air or water during drilling, but also for grouting the hole.
  • Choice of drill bits for different ground conditions
  • Enhanced corrosion protection is available upon request