Experimental Investigation of the Progressive Failure of Multiple Pillar–Roof System

Excerpt

In room-and-pillar mining systems, pillars are left to support the overlying rock strata and prevent collapses. Thus, pillar stability is an important prerequisite for safe working conditions and avoiding roof fall accidents (Ghasemi et al. 2014; Zhao et al. 2017). A great deal of effort has been devoted to investigating the mechanics characteristic of a single pillar (Martin and Maybee 2000; Zhou et al. 2017a). For instance, several empirical formulae for pillar strength have been proposed that take into consideration both failed and sucessful pillar cases from various databases (Hustrulid 1976; Esterhuizen et al. 2011). Elmo and Stead (2010) applied an integrated numerical modelling-discrete fracture network approach to analyse the failure modes of naturally fractured pillars. Salmi et al. (2017) used a modified tributary area method to analyse the lifetimes of pillars when considering the effects of deterioration rates and then assessed the stabilities of the shallow abandoned room-and-pillar coal mines. …