Bhawani Singh, R. K. Goel, J.L. Jethwa, A. K. Dube

Himalayan tunnels provide challenging opportunities for working on the problems of assessment of support pressure in tunnels. A resume of the efforts by Indian researchers on this topic is presented in the paper, with a brief review and comparison with the approaches of Bieniawski (1979) and Barton et al. (1974; Analysis of Rock Mass Quality and Support Practice in Tunnelling, A Guide for Estimating Support Requirements, Report by NGI, June). It is noted that Goel's classification of tunnelling conditions (Goel, 1994; correlations for Predicting Support Pressures and Closures in Tunnels, Ph.D. Thesis, Nagpur University, India, p.308) is complementary to the Q-system. Contrary to Terzaghi's theory, support pressures are observed to be independent of opening size.