ASSESSMENT OF ROCK MASS QUALITY WITH BLAST-INDUCED DAMAGE AT THE DAM SITE OF JINPING I HYDROPOWER STATION

Jinping Ⅰ hydropower station is a double-curvature arch dam, the designed height of which is 305m. The foundation rock masses are mainly assigned to class Ⅱ, Ⅲ₁. The rock masses are damaged in different degrees during the blasting excavation. For assessing the degree of rock mass damage quantitatively, the detection results of blasting excavation are used, in which rock mass relaxation depth and single-hole sonic attenuation of the relaxation rock after excavation are applied as an indicator to classify the degree of rock mass damage. A rapid detection method and classification standard of rock mass damage are proposed. Evaluation of rock mass damage after dam excavation is completed and treatment suggestion is proposed for the rock mass under different degree damage.