The Key to Keeping Tunnel Portals Safe

Tram, train and metro tunnels offer passageway for thousands of commuters and goods every day. It is fair to say that tunneling remains one of the most intricate civil engineering challenges globally. These technological masterpieces have driven the market for new and updated solutions to complex problems over the years to keep them safe for public and private use.


Preventing Portal Problems in Mining and Tunneling Industries


Mining and tunneling industries involve a number of risks and hazards including rock falls, scaling, mud inflow, and explosions.

Collapse may occur in any of the following circumstances:

  • Face or crown collapse
  • Collapse along finished tunnel length
  • Tunnel portal collapse

Due to limited escape options, designers must identify and solve portal problems as early as possible to ensure the safety of people and equipment. Hollow bars can be one of the most effective solutions to help prevent portal problems like these from occuring.


The Effectiveness of Hollow Bars and Rock Drills


The hollow bar system is easily the most popular method for holding in position collapsing, or loose soil at tunnel portals. A threaded steel bar is drilled into the soil and grouted into place. The hollow center in the bar acts as a conduit for simultaneous grouting and drilling. It features a rope thread that connects to drilling equipment. Drill bits, rock bolts, and soil nails normally accompany the hollow bars in the portal stabilization process.

Since it is created by a cold rolling manufacturing process, hollow bars have:

  • A refined grain structure
  • High yield strength
  • A wide range of applications

These bars offer excellent support in different ground conditions and types of soils around the tunnel portal.


Partner with TEI Rock Drills to Keep Your Workers Safe


According to the Safety and Health Regulations for Underground Construction, portal openings, access areas, and adjacent areas shall be secured and guarded for safety within the portal and in access areas.

TEI Rock Drills is a leading manufacturer of excavator rock drill attachments, rock drill components, and limited access rock drill rigs. By partnering with us you can apply state-of-the-art measures, like hollow bars installed using hi-tech rock drills, to help you keep employees as well as the public safe and limit downtime.

Learn more about your options for hi-tech rock drills from Or call our corporate office at 1-800-777-3745.