The characteristics of blasting vibration frequency bands in jointed rock mass slope
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ORIGINAL ARTICLE
The characteristics of blasting vibration frequency bands in jointed rock mass slope Shenghui Zhang1 · Wenxue Gao1 · Lei Yan2 · Jiangchao Liu1 · Liansheng Liu2 Received: 9 July 2020 / Accepted: 30 October 2020 / Published online: 16 November 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
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. Keywords Blasting vibration · Peak particle velocity · Frequency · Joints · Vibration attenuation List of symbols ẍ Acceleration of the rock mass element ẋ Velocity of the rock mass element x Displacement of the rock mass element 𝜔 Excitation frequency 𝜔0 Natural frequency of the slope 𝜁 Damping ratio c Viscous damping coefficient m Mass of the rock mass element t Time 𝜏 Specific time v0 Initial velocity * Liansheng Liu [email protected] 1
College of Architecture and Civil Engineering, Beijing University of Technology, Beijing 100124, China
School of Resource and Environmental Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, China
2
d0 Initial displacement I Instantaneous impulse p Blasting load d𝜏 Micro-segment dt Time step-size dx Displacement step-size 𝜓(t) Arbitrary signal L2 (R) A signal space with limited energy R Re
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