OPEN-FACE BORERS IN ITALIAN ALPS

This article reviews the use of open-face tunnel boring machines (TBMs) for hydroelectric scheme tunnels and pilot tunnels for railways and roads in the Italian Alps. The pilot tunnel technique was mainly developed by Italy, and can provide much data about underground conditions and data used for cost estimates. Pilot tunnels can sometimes be enlarged to full-size tunnels by using appropriate drill-and-blast techniques. Pilot tunneling by TBM is also playing an important part in the NEAT (New European Alpine Transit) project in Switzerland. The article considers the use of open-face TBMs in the Prato Isarco, Val d'Arzino, and Spriana tunnels. It also discusses: (1) the O-norm B2203 rock classification system, developed specifically for TBM tunnelling; (2) causes of major collapses at TBM projects in the Alps, and how to recover from such collapses; and (3) the following rock reinforcement facilities and techniques: (a) rock bolts; (b) bolting equipment; (c) probe drilling; (d) forepoling and jet grouting; (e) an over-boring system; and (f) steel ribs. The new-generation TBMs have high thrust, increased cutterhead power, and cutters with larger diameters; they can reach penetration rates exceeding 4-6n/h, even in tough granite. In stable rock formations, average advances can exceed 40m per day.

  • Availability:
  • Corporate Authors:

    THE MINING JOURNAL LTD

    60 WORSHIP STREET
    LONDON,   United Kingdom  EC2A 2HD
  • Authors:
    • SCOLARI, F
  • Publication Date: 1995-11

Language

  • English

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00720788
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD
  • Created Date: May 24 1996 12:00AM