爆破振动信号时频特征的三维分形特性研究

为进一步研究爆破振动信号能量特征,基于小波包变换方法对爆破振动信号时频能量特征进行分析。在二维矩形盒维数模型的基础上建立了计算三维曲面分形盒维数模型,并计算得到实测爆破振动信号时频能量谱的三维分形盒维数D3d=2.148 8。该分形维数满足空间分形条件2D3d3,验证了爆破振动信号时频能量谱具有三维分形特征。经研究三维分形曲面盒维数D3d与其剖面二维分形盒维数D2d之间的数值关系,表明计算空间分形曲面分维数的常规假设D3d=D2d+1并非严格成立。研究表明,所提出的长方体覆盖空间曲面的分形维数计算方法可行、有效,为进一步研究爆破振动信号特征、控制爆破地震效应提供了新的研究思路。

Three-dimensional fractal study on time-frequency characteristics of blast vibration signal

To further study the characteristics of blast vibration signals, time-frequency energy character-istics of blast vibration signals were analyzed based on wavelet packet transform. The three-dimensional fractal surface box dimension model was established based on two-dimensional rectangular box covering method. By analyzing the measured blasting vibration signal data, fractal dimension of the three-dimensional time-frequency energy spectrum is 2.1488, which meets the condition for space fractal dimen-sion , and verifies that the time-frequency energy spectrums of blasting vibration signals have fractal characteristics. By studying the relationship between the three-dimensional fractal surface and two-dimensional box dimension of its section, the assumption of for traditional surface fractal dimension calculation method is not exactly. The study indicates, cuboids’ covering surface calcula-tion method for fractal dimension is feasible and effective, which provides a new idea for further study of blast vibration characteristics and the blasting seismic effect control.