The characteristics of blasting vibration frequency bands in jointed rock mass slope

Abstract

High-slope and rock mass joint development are the factors for predicting and controlling blasting vibrations under open pit mining. Blasting vibration adversely affects the stability of jointed rock slopes, thus studying the characteristics of blasting vibration frequency bands in jointed rock masses slope is an important task to ensure the safety of blasting operations. In the present study, vibratory ground motions were measured during blasting excavation in open-pit mining, and the blasting vibration frequency band characteristics of jointed rock masses and high slope were studied through the wavelet transform and response spectrum method. The results demonstrated that the amplification effects of the peak particle velocity (PPV) and energy between different frequency bands exhibited distinguishing characteristics. It was found that, with the increase in elevation, the PPV and energy amplification effects were the most obvious in the 0–16 Hz band, while they were attenuated in the 32–64 Hz band. Furthermore, the distribution of dominant frequency bands of vibration signals observed to be low and narrow, and the average frequency had been reduced. In the development of joints in rock masses, the PPV and energy in each frequency band were attenuated, and the distribution of the dominant frequency bands of vibration signals was high and wide. Also, the average frequency had been increased and the multi-modal characteristics of the responses to blasting vibrations were more obvious. The rock mass structures had displayed different amplification effects on the frequency components of the blasting seismic waves. Finally, as the effects of jointed rock masses on the blasting load responses could not be simply considered as reducing vibrations, they must be analyzed using vibration theory and actual situations.