The excavation of a deep hard rock roadway or tunnel is easy to induce a spalling roughly parallel to the excavation surface of surrounding rock,which seriously affects the stability and safety of deep engineering.The formation of spalling are related to the lithology and stress environment of deep rock before excavation and the stress paths experienced by surrounding rock during roadway excavation.La⁃boratory test is an important method to study the spalling of deep surrounding rock,and the key to obtaining the spalling characteristics and sc...
