Vibration characteristics of blasting in bed rock mass at Sanxia Project

摘要

Taking the excavation blasting of bed rock mass in Sanxia Project as the background, six blasting experiments have been done at the bottom of weak weathering granite in Sanxia dam and the 36 sets of seismic waveform at different positions away from the explosion sources are measured. Through the analyses of both frequency and statistics, it is found that the vibration frequency varies inversely as both the charge weight and the distance away from the explosion source and that the duration of seismic waves varies directly as the charge weight and inversely as the distance. The attenuation law of seismic waves is determined by applying the neural network theory. Meanwhile, the microcracking zone boundaries of rock mass in blasting are measured using the computer tomography (CT) and their corresponding critical vibration velocities of rock particles are also calculated.