The damage area is much larger than the blasting excavation area

so rock mass would be damaged several times and result in accumulative damage. The left bank diversion tunnel at Wudongde hydropower station is monitored and simulated for blasting vibration and rock mass deformation during excavation. Based on accumulative damage theory

the damage threshold and damage variable are adopted to consider the parameter weakening in different damage areas. The weakened rock mass parameter is adopted in each damaged element

and numerical simulations are conducted to simulate the accumulative damage induced by blasting excavation. By comparing monitored data and calculation results

the results considering accumulative damage is more close to the monitored values of both blasting vibration and rock mass deformation. Therefore

in numerical simulations of blasting excavation of tunnels

accumulative damage effect should be considered.