ABSTRACT
Ground Support in Mining and Underground Construction-Villaescusa & Potvin (eds.) © 2004 Taylor & Francis Group, London, ISBN 90 5809 640 8
ABSTRACT: The paper briefly describes common reasons for rock failure and support installation in tunnel construction. Where tunnelling conditions cannot be calibrated to local experience or classification systems, the need for a thorough site-specific investigation of rock conditions is emphasized. This investigation should permit recognition and analysis of the full range of potential rock failure modes. The use of rock mass classifications systems in blocky rock conditions is discussed, as well as the need for complementary analyses and support criteria when developing tunnel designs in rock masses where there is a possibility of encountering heavily fractured or soil-like zones, overstress and/or swell/slake behaviour. The need for analyses that complement rock mass classifications is underlined by reference to a recently completed set of tunnels excavated in dolomite, siltstone and shale for the Neutrinos at Main Injector (NuMI) Project.
