REINFORCING THE ENA-SAN TUNNEL

Large-scale rock faults and the effects of hydrothermal action have caused construction problems of Japan's Ena-San tunnel. With an overall length of 8500 M the tunnel is the second longest vehicle tunnel in the world compared with Europe's Mont Blanc tunnel. The Ena-San Tunnel has a vehicle capacity of 2000 vehicles per hour compared with the 450 vehicles per hour of the Mont Blanc tunnel. Severe hydrothermal action on a section of granite has caused earth pressures of 70-100 t/sq M. To counteract this the side drift method of reinforcement was used with double steel h-shaped supports and a concrete lining. To repair sections of this lining, cracked by earth pressure, the lining was replaced by a steel-fibre reinforced secondary concrete lining applied using steel lining forms and concrete pumps. The fibre/concrete mix used Tesusa fibres measuring 0.5 X 0.5 x 30 mm long in a 1.5 per cent by volume mix having A compressive strength of 400 kg/sq cm and a bending strength of 100 kg/sq cm.

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  • Corporate Authors:

    Morgan-Grampian (Professional Press) Limited

    Morgan-Grampian House, Calderwood Street
    London SE18 6QH,   England 
  • Publication Date: 1976-10

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Filing Info

  • Accession Number: 00159771
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Report/Paper Numbers: Analytic
  • Files: ITRD, TRIS
  • Created Date: Dec 27 1977 12:00AM