A simplified model of local fracture processes to investigate the structural stability and design of large-scale tabular mine layouts

摘要

The stable and safe mining of deep tabular excavations is an ongoing problem of considerable technical and economic interest requiring an understanding of the interactions between local rock failure processes (metre scale), the structural impact of the overall layout shape (tens to hundreds of metres in scale) and the regional mobilization of geological structures (kilometer scale). In this paper, a limit equilibrium model is used to simulate local on-reef fracture processes that may also exhibit time-dependent failure characteristics. The traditional energy release rate design criterion (ERR) is re-interpreted as a metric of extraction sequence stability by including explicit energy dissipation mechanisms in the computational framework. A desirable feature of the limit equilibrium model outlined here is that it provides an explicit representation of the extent of the fracture zone near the edges of a tabular excavation that is responsive to regional stiffness variations induced by individual mining pattern configurations. The model is illustrated by considering the extraction of a raise connection through a pillar and by observing the implications of mining rate changes at one edge of a parallel-sided panel on released energy values.