Study on the safety velocity for concrete lining under P wave loading

The vibration is induced by blasting during tunnel excavation that can have some adverse effect on the adjacent concrete lining. A theoretical method to determine safety velocity of concrete lining under blasting vibration loading is proposed, by calculating the stress on concrete-rock interface caused by blasting seismic (P wave), and analyzing the tensile strength of the interface. Calculated results show that the safety vibration velocity decrease with the increase of elasticity modulus of bedrock, and that the effect of the frequency of blasting seismic is weak. The safety vibration velocity for young foundation concrete adopted in our country is of some safety.