APPLICATION OF SHOTCRETE IN THE NATM (OPERATING EQUIPMENT, PAYMENT PROVISIONS AND PRACTICAL EXAMPLE)

The New Austrian Tunneling Method (NATM) is a double shell building method consisting of a shotcrete outer arch (reinforced by welded wire fabric and steel rib sections) and a systematically anchored rock carrying ring. The rock carrying ring is the primary supporting element and thus of the greatest importance. The advantages of shotcrete in the NATM lie primarily in its good applicability in sealing exposed cavities as fast as possible and thereby avoid detrimental loosenings around the rim of the cavity; besides, it provides immediate protection for the crews. In the rock conditions encountered at the Arlberg West tunnel there was, however, a critical ridigity of the shotcrete outer arch. If said critical point was surpassed, shear fractures were the result. This rigidity of the shotcrete outer arch could be avoided by a methodical placement of contraction slots (fault slots) which keep the shotcrete shell from being destroyed. The paper discusses the excavation method used at the Arlberg West tunnel and the operational equipment used for applying shotcrete.

Media Info

  • Pagination: p. 297-322

Subject/Index Terms

Filing Info

  • Accession Number: 00173551
  • Record Type: Publication
  • Source Agency: Engineering Index
  • Report/Paper Numbers: ACI Pub SP-54 Proceeding
  • Files: TRIS
  • Created Date: Jun 28 1978 12:00AM