ABSTRACT
The presented paper deals with the self-supporting ring, formed by non-prestressed fully grouted rock bolts and the surrounding rock mass, around an extended cavity in squeezing rock. The self-supporting ring is considered as a separate statical system. To determine the global strength properties of this composite system studies of the stress-strain behaviour of an idealized ring element consisting of bolts and the rock mass were made. Results from variations of geometrical parameters obtained from model tests and finite element calculations are presented. They confirm the exponential increase of the system strength when the bolt distance decreases linearly. These and further studies shall result in a self-contained composite theory, which considers the bolt-rock mass system as an anisotropic compound system.
