ABSTRACT
Shotcrete has been used for rock support in tunnels for many years, and is known to be a very satisfactory means of support. Traditionally, the design of shotcrete support has been based on the assumption that the shotcrete layer acts as a structural arch (similar to a thin cast concrete lining) or as a series of beam elements acting between point supports provided by rockbolts or cables. Whilst this design approach may be acceptable in civil engineering practice, where conservatism is necessary to ensure long term stability, it is not appropriate in a mining environment in which stability margins must usually be much less conservative. In fact, in such an environment, some instability should occur to prove that mining is being carried out economically. Such instability should not occur unexpectedly, however, nor result in unsafe conditions.
