ABSTRACT
This paper presents a preliminary study to investigate possibilities for standardizing and optimizing rock support system for typical tunnelling conditions in Sweden. The support design methodology in Sweden was established for three decades ago, with focus on the adhesion strength between shotcrete and rock surface. The design methodology has shortcomings. For instance, the choice of rock supports during rock constructions based on on-site judgements of the adhesion strengths is troublesome, because the past experiences show that the adhesion strengths have significant variations. Questions have, therefore, been raised on the rock mechanics bases for the design methodology and more rational rock support systems are wished. This paper is an attempt to propose an optimized rock support system based on enhanced analyses of the support mechanisms as well as sound engineering judgements.
