Cracking characteristics of rock-anchored beam system during construction of underground powerhouse under high in-situ stress and complex rock mass structures: A case study of Yebatan hydropower station - Peiyang Yu; Xiuli Ding; Shuling Huang; Xinhao Zhu; Yang Qin; Jianhua He; Yuting Zhang; Gang Han (Tunnelling and Underground Space Technology, 2026)