传播介质特性对爆破震动信号分析中小波包时频特征的影响

传播介质是指爆破震动赖以向外传播的地层介质 ,其基本特征是影响爆破震动时频分布的主要因素之一。当传播介质中有爆破震动通过时 ,其动态响应将会因其原地结构的不同而在响应持续时间、频谱、响应的衰减等特征方面均有较大差异。本文利用岩体 (岩土混合体 )基本质量指标BQ值以及完整性系数Kv 来量化传播介质特性。通过对不同岩层地质条件下产生的爆破震动进行小波包分析 ,探讨了传播介质特性量化参数与爆破震动时频分布之间的关系。研究中发现 ,传播介质特性对单段波形小波包细节信号的主振频带分布、峰值质点振速及衰减阻尼比等时频特征参数均有较大影响 ,其中主振频带分布范围随着传播介质的完整性系数Kv 值减小而增大 ,优势频率值随完整性系数Kv 值减小而增加 ,而峰值质点振速及衰减阻尼比与完整性系数Kv 值之间的规律性不强

EFFECT OF PROPAGATION MEDIUM PROPERTY ON TIME-FREQUENCY CHARACTERISTICS OF BLASTING VIBRATION WITH WAVELET PACKETS ANALYSIS

The propagation medium involved in this paper refers to a rock mass or stratum in which blasting vibration waves are transmitted Its property is one of main influencing factors for the time frequency characteristics of blasting vibration When a blasting vibration goes through the propagation medium,the different structures of the propagation medium will bring on a great difference in dynamic response with respect to duration and attenuation of response and frequency spectrum In this paper,the Basic Quality(BQ) index and the integrality coefficient K v of rock mass or rock soil hybrid are used for quantization of propagation medium property,and the relationship between the quantization parameters of the propagation medium property and the time frequency distribution of blasting vibration is discussed through analysis of vibrations from blasts in different strata by wavelet packets It is found in experimental investigation that the property of the propagation medium has asignificanteffectontheparametersofdescribingthetimefrequencycharacteristicsofthedetailedsignalswithwaveletpacketsanalysis,suchasdominantfrequencybandwidthdistribution,peakparticlevelocityandattenuationdampratioThedistributingscopeofdominantfrequencybandwidthandthevalueofdominantfrequencyinsuchbandwidthincreaseastheintegralitycoefficientKvdecreasesThepeakparticlevelocityandtheattenuationdampratioofthedetailedsignalshavenostrongrelationtotheintegralitycoefficientKv