Abstract: Loading experiment process, safety monitoring method and results of rock-anchored beam in Jinping I hydropower station underground powerhouse, are introduced. The results show that anchor stress,crack openings, rock deformation and anchoring load losses are caused by secondary stress; their increments caused by test loads is far less than monitoring physical quantities; most of the anchor bolts stresses are tensiles. C anchor stress increment reflects more sensitive than A, B anchor stress increments; anchor stress increment diminishes quickly with the buried depth increases; during the whole process, all levels of load variation monitoring physical quantities are less than their design control standard values. It is suggested that the rock anchor beam design and construction should consider surrounding rock and rock anchor beam jointed effects in surrounding rock deformation.

Key words: rock-anchored beam, loading experiment, safety monitoring ;stress of anchor, Jinping I hydropower station