Comparative Analysis of the Effects of Excavation Unloading and Blasting Vibration on the Disturbance of Underground Caverns
In the construction of underground caverns by drilling and blasting,excavation unloading and blasting vibration are two common construction disturbances that the surrounding rock withstands.By analyzing the simulation methods for the two construction disturbances,we believe that the numerical simulation method for excavation unloading is relatively mature,whereas for blasting vibration,dynamic time history method should be adopted as it takes into account the dynamic loading effect of blasting and better reflects the blasting effect on surrounding rock.Considering the excavation unloading and blasting vibration effect,we conducted mechanical response analysis of surrounding rock in underground cavern for the underground powerhouse of pumped storage power station.By comparing the degree of effect of different construction disturbances on the stability of surrounding rock,we found that blasting vibration has a certain influence on the deformation of surrounding rock,especially the deformation of structural plane,but this effect is significantly less than that of excavation unloading.Therefore,as long as the blasting intensity and rock vibration level can be effectively limited during the construction process,the impact of blasting on the stability of surrounding rock can be effectively controlled.Moreover,excavation unloading and blasting load may trigger significant mechanical response in surrounding rock area crossed by structural plane,which,thus,should be the key focus in the support of surrounding rock local strengthening.
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