Macro- and Microstructural Characteristics of the Tension–Shear and Compression–Shear Fracture of Granite

Excerpt

In various complicated geological conditions, the redistribution of stress in rock masses due to excavation unloading activities causes many failure accidents and is a critical issue in the safety and stability of rock structures (Durrheim et al. 1998; Wu et al. 2009; Zhang et al. 2012; Xu et al. 2017). Tensile stress concentrations often occur in fractured rock masses under unloading conditions, which will lead to the tension–shear failure. For fractured rock masses, different types of mechanical tests have been conducted (Huang and Li 2014; Huang and Huang 2014) to explore the fracture mechanism of rocks and the evolution of cracks. The results indicate that rock usually fails in three modes: tension, tension–shear and shear. In recent decades, a number of researches (David et al. 2005; Maximiliano et al. 2014; Meng et al. 2016, 2018a, b, 2019) have been conducted to study the shear mechanical behaviors and deformation characteristics of rock joints under compressive stress. However, the shear fracture mechanism of rock under tensile stress is often neglected, and a systemic study on rock in a tension–shear condition is lacking. …