About 10 years ago a Swiss engineer, John Bernold, designed a tunnel support system that needs three requirements: (1) It seals off rock from the effects of air slacking and water entrainment; (2) It immediately provides a strong temporary support for the miners: (3) All of the steel placed can be used as part of the permanent tunnel support structure. With the Bernold system, shot-crete is supported, and together with the steel plates, has a very high shear strength. This support system, in addition to providing safety for tunnel employees, substantially reduces the work effort, because the need for vast quantities of temporary timber lagging no longer exists; it reduces the amount of steel needed for the permanent support; it eliminates the need for large quantities of concrete to cover a tangle of temporary steel arches and a mat of re-steel. This system can be compared to a thin arch dam, and it reacts to extreme ground forces by flexing to shift the load. A great number of tunnels in Europe have used the Bernold systems safety approach for tunnel support. The St. Gotthard Highway Tunnel through the Swiss Alps is notable for the use of this system. The subways in Tokyo also have used this system to good advantage. The Bernold system has been used in almost 1,000 miles of tunnels, and not one has fallen. It is stated that the Bernold system can easily meet the safety requirements of OSHA, the U.S. Corps of Engineers, and the State of California Tunnel Orders.

  • Corporate Authors:

    National Safety Council

    425 North Michigan Avenue
    Chicago, IL  United States  60611
  • Authors:
    • MacCollum, D V
  • Publication Date: 1976-12

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00157246
  • Record Type: Publication
  • Source Agency: Engineering Index
  • Files: TRIS
  • Created Date: Aug 4 1981 12:00AM