ANALYSIS OF SQUEEZING OF. TUNNELS IN JOINTED ROCKS

Abstract

This thesis deals mainly about the tunnelling under squeezing rock conditions. In India, the rock masses in Himalayas pose unique problems to tunnels. One such problem is squeezing in tunnels in jointed rock masses. Assessment of squeezing potential in jointed media is an unresolved problem till date. That is why; the squeezing is recently receiving great attention in the field of rock mechanics and tunnelling. In the present work, various approaches have been discussed for identification and quantification of squeezing, along with the empirical and semi-empirical approaches presently available in order to anticipate the potential of squeezing tunnel problems. A methodology proposed by Singh et al. (2004) has been used to predict the closure around the periphery of.the tunnel which is based on the constitutive modeling as. is presented by Haung et al. (1995). In this methodology constitutive equations are given for plain strain deformations in uniaxial, biaxial and triaxial conditions. This methodology is applied to a case study and validated the .results, through programming and FEM analysis. The methodology is also applied to data collected on different case studies and validated the results, through programming.