SAFETY CRITERIA OF BLASTING VIBRATION IN HYDROPOWER ENGINEERING AND SEVERAL KEY PROBLEMS IN THEIR APPLICATION

The status and progress of the mechanism of blasting vibration-induced failure or damage,the evaluation method of dynamic stability for rock slope and surrounding rock mass of underground caverns under blasting vibration,and the influence of blasting vibration on early-aged concrete,etc.,are introduced and analyzed. The domestic safety criteria of blasting vibration and permitted standard of blasting velocity for high rock slope, underground caverns,foundation rock mass and early-aged concrete adopted in field of hydropower engineering are presented,which are compared with those employed in fields of mining. Main problems existing in the study of the damage mechanism induced by blasting vibration and deficiencies of currently adopted safety criteria are analyzed and discussed such as no distinction between different damage mechanisms induced by propagation of blasting seismic wave in rock mass and by dynamic response of rock slope and no consideration of influence of vibration frequency and duration on the adopted safety criteria. Finally,some proposals are given to further study in the fields of damage mechanism of blasting vibration,comprehensive safety criteria expressing blasting vibration incorporating factors of vibration amplitude,frequency and duration,allowable vibration standard for early-aged concrete considering the influence of thermal stress,etc..