LI Zhiwen 1,2, LI Jianchun 1, HONG Shengnan 1,2, LI Haibo 1, ZHANG Guokai 1,2,3
JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 107-114.
Due to geometric diffusion of wave fronts and absorption of medium,amplitude and frequency of blasting seismic waves have a series of changes in their propagation process. In order to study generation and propagation laws of blasting seismic waves,rock mass was considered as a viscoelastic medium,blasting loads were equivalently exerted on the boundary of the vibration zone,the integral solution to the problem was obtained in frequency domain. The numerical calculation and parametric analysis were done for the integral solution. The results showed that the shorter the rise time of blasting loads,the larger the boundary vibration amplitude of the vibration zone; the longer the duration for blast loads lasting,the longer the duration for the boundary vibration lasting,but the vibration amplitude is not influenced; under the action of the same blasting loads,the smaller the medium’s elastic modulus and viscosity coefficient,the larger the boundary vibration amplitude; geometric decay of blasting seismic waves is divided into near-field attenuation and far-field attenuation,the decay rate of near field is obviously larger than that of far field; with increase in the ratio of viscous coefficient to elastic modulus,medium absorbs blasting seismic waves more obviously; with increase in the propagation distance of blasting seismic waves,their higher frequency components decrease relative to their lower frequency components,the larger the viscosity coefficient,the faster the decrease speed.