Rock bolt supporting factor: rock bolting capability of rock mass

Abstract

Rock mass classification has played a crucial role in underground construction and mining projects in the past fifty years, especially the Rock Mass Rating (RMR) and Rock Tunneling Quality Index (Q) systems, which have been applied in many cases. The parameters of discontinuity conditions in the RMR system, along with the related ratings, were used to develop a new equation in order to introduce an intrinsic quality of a given rock mass, namely, rock bolt supporting factor (RSF). The RSF was used to develop a mathematical theory of the rock bolt supporting mechanism as a new principle in explaining rock bolting effects. Finally, using the parameters of the discontinuities in the Q-system, the QRSF is defined to present the capability of a given rock mass to be reinforced by rock bolting. The RSF leads to more reliable judgment of rock bolting capability of a given rock mass than the QRSF since it uses five parameters of discontinuity conditions while the QRSF uses only two parameters.