EMERGENCY IN THE VALTELLINA VALLEY: TWO BORING MACHINES MAKE NEW TUNNELLING RECORD POSSIBLE. SECOND INTERNATIONAL TUNNELLING SYMPOSIUM, MUNICH, 12 APRIL 1989

This paper describes the construction of the diversion tunnels, together with the relevant intake and outlet works, that were constructed to bypass a landslide in the Valtellina Valley in North Italy. The tunnels were required to empty a lake upstream of the landslide before it flooded the neighbouring land. They were sized with sections allowing the Adda River to discharge possible exceptional floods up to 400 cu m per sec. The building of the tunnels was completed very rapidly, between November 1987 and April 1988. One tunnel has length 2.854 km, approximate diameter 6.0 m and a polycentric section; the other tunnel has length 2.898 km, diameter 4.2m and a circular section. Both tunnels have approximate gradient 2.52%. In the first tunnel, a Tunnel Boring Machine (TBM) was used to drive a pilot tunnel of diameter 3.0 m, which was then enlarged by blasting; the second tunnel was drilled by a TBM. It was found that the greater excavation costs of boring the pilot tunnel, due to use of a TBM, were more than compensated by: (1) the lower specific costs for explosives; (2) the reduced need for tunnel supports; (3) less overbreak; (4) a smaller work force; (5) lower total cost, due to reduced execution times. The German title of this paper is as follows: "Katastrophe im Veltlin-Tal - zwei Tunnelbohrmaschinen ermoeglichen einen Zeitreleord im Tunnelbohren". For the covering abstract of ths conference see IRRD 824157.

• Corporate Authors:

  Mining Journal Limited

  60 Worship Street
  London EC2A 2HD,   England 
• Authors:
  • Golinelli, G
• Publication Date: 1989-4

Language

• Undetermined

Media Info

• Pagination: p. 24-27
• Serial:
  • World Tunnelling and Subsurface Excavation Special
  • Publisher: Mining Journal Limited

Subject/Index Terms

• TRT Terms: Conferences; Construction; Costs; Excavation; Excavations; Full face tunneling; Tunneling machines; Tunnels
• Geographic Terms: Italy
• Subject Areas: Bridges and other structures; Construction; Finance;

Filing Info

• Accession Number: 00498523
• Record Type: Publication
• Source Agency: Transport and Road Research Laboratory (TRRL)
• Files: ITRD, TRIS
• Created Date: Sep 30 1990 12:00AM