On Acoustic Emission and Post-peak Energy Evolution in Beishan Granite Under Cyclic Loading

Excerpt

Cyclic tests (loading–unloading) provide an effective way for a better understanding of damage and deformation characteristics in rocks. In general, elastic and plastic strain components can be distinguished during cyclic experiments (Elliott and Brown 1986). In addition, the influence of accumulated damage on rock strength can be studied by this method (Martin and Chandler 1994). Detectable acoustic emission (AE) signals are emitted when the specimen is loaded, and AE monitoring techniques have been used to provide a detailed view of fracture nucleation and growth (Lockner et al. 1991; Thompson et al. 2005, 2006; Cai et al. 2001, 2007; Cai and Kaiser 2005). Since the AE events are closely related to the damage or fracturing of the rock, rock degradation or damage can thus be measured (Falmagne et al. 1998). Furthermore, energy is dissipated during the whole failure process and can be quantified (Xie et al. 2009, 2011; Wasantha et al. 2014). In this study, cyclic tests were carried out on Beishan granite chosen as potential host rock for a high-level radioactive waste (HLW) repository in China (Wang 2010). AE recording system was utilized to monitor the fracturing process during the test. In addition, based on stress–strain curves, the energy evolution in the post-peak stage of Beishan granite was studied. …