爆破振动频率的研究是爆破振动危害控制技术发展的重要基础。基于引入介质阻尼项建立的黏性岩体爆破振动频谱表达式,并结合LS-DYNA有限元软件,数值模拟分析球状药包爆破振动主频和平均频率的衰减机制和规律;针对柱状药包,利用数值模拟其爆破振动频率的衰减规律。结果表明:无论是球状药包还是柱状药包,由于爆破地震波频谱曲线的多峰结构和高低频衰减速度的差异,其爆破振动主频随爆心距的增大并非严格的衰减,在衰减过程中出现局部突变或者波动,而爆破振动平均频率则随爆心距规则地衰减。该理论分析结果得到了工程实测振动资料的验证。
Frequency analysis of blast vibration is one of the important foundations for developing the control technology of blast vibration damage. Based on the spectrum expression of vibration with a damping term for the spherical charge in tough rock mass and LS-DYNA numerical simulations,the attenuation of dominant frequency and average frequency of blast vibration were analyzed. The attenuation of dominant frequency and average frequency of blast vibration induced by cylindrical charge were studied with the numerical simulations. The results show that for both the spherical or cylindrical charges,the dominant frequency of blast vibration does not attenuate strictly with the increasing of distance to the blast site. Both the multimodal structures of vibration spectrum and the difference of decay rate between the high-frequency and the low-frequency contribute to the mutation or fluctuation at some distance during the frequency attenuation. The average frequency has the pattern of regular attenuation. Theoretical analysis results were validated by the empirical data gotten from engineering.