Abstract：On the basis of the numerical simulation of dynamic finite element method(DFEM)，the dynamic response of rock-anchored beam of large underground powerhouse under blasting vibration is studied. It is found that the key to ensure the safety of the rock-anchored beam under blasting vibration is to prevent the cracking of the bonding interface between the beam and the vertical rock wall，and to control the horizontal peak particle velocity，which is vertical to the side wall. Combined with the blasting vibration control practice of the rock-anchored beam at Longtan Hydropower Station，considering the comprehensive factors such as the structure characteristic of rock-anchored beam，the strength properties of concrete，the strength development with the increase of the cured age of young concrete，the microstructure and the strength of the bonding interface，the feasibility of rock excavation by blasting in underground powerhouse below the beam is studied under the condition that the cured age of concrete is no older than 28 d；the control standard of peak particle velocity(PPV) for rock-anchored beam in different cured ages is proposed. It is concluded that the PPV control standard for young concrete proposed by code could be used to rock-anchored beam with an age no older than 28 d；and the PPV of 7 cm/s for rock-anchored beam with an age older than 28 d has certain safety margin.
