Abstract
In this paper, an attempt is made to apply the fuzzy sets theory to the rock mass classification of granite tunnels. By using the fuzzy regression analysis, it is possible to develop an objective and simplified equation to classify rock masses, which can be applied to a tunnel face under construction. Each classified region derived from the proposed equation has sectional and continuous values with possibility distribution. Discussions on the adequacy of the equation in rock engineering, the comparison with the usual statistical approach and a methodology of modification to adapt it to each granite tunnel are mentioned.
