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爆心至测点的位置条件是影响爆破震动时频分布的主要因素之一。在考虑到段药量变化的情况下,位置条件由比例距离和高差系数来进行量化。运用小波包分析方法对监测获得的爆破震动信号进行时频特征分析,探讨时频分布与比例距离及高差系数之间的关系。试验研究发现,位置条件对震动波形小波包细节信号时频特征的影响主要体现在峰值质点振速、优势频率大小及波形衰减阻尼比的变化上。其中峰值质点振速随比例距离的增加呈指数衰减,其与高差系数的相关规律性不强;优势频率随比例距离增加也呈衰减趋势,高差系数对其有较大影响,但规律不明显;衰减阻尼比在不同的主振频带内与比例距离及高差系数有不同的关系,较低频率部分其阻尼比随着比例距离的增加而增大,较高频率部分则基本保持不变。
The location condition of blasting heart to measuring point is one of the main factors affecting the time-frequency distribution of blasting vibration. Taking into account the changes in the amount of drug case, the location conditions by the proportional distance and height coefficient to quantify. The time-frequency characteristics of blasting vibration signals obtained by monitoring are analyzed by wavelet packet analysis, and the relationship between time-frequency distribution and proportional distance and height difference coefficients is discussed. Experimental results show that the influence of location conditions on the time-frequency characteristics of the wavelet packet detail signal is mainly reflected in the change of the peak particle velocity, the dominant frequency, and the damping ratio of the waveform attenuation. Among them, the peak particle velocity decays exponentially with the increase of the proportional distance, and the correlation regularity between the peak velocity and the differential coefficient is not strong. The dominant frequency decays with the increase of the proportional distance, but the difference coefficient has a great influence on it. However, Obviously, the damping damping ratio has different relations with the proportional distance and the height difference coefficient in different main vibration frequency bands. The damping ratio of the lower frequency part increases with the increase of the proportional distance and remains unchanged at the higher frequency part .