含多种尺寸缺陷岩体中的弹性波散射

Scattering of Elastic Waves by Multi-Size Defects in Rock Mass

研究了含多种尺寸扁平椭圆缺陷的岩体中弹性波散射规律.细观上应用Green函数方法,考虑了入射波与基本的扁平椭圆缺陷相互作用,宏观上采用线性叠加原理,得到了缺陷岩体的频散和衰减规律.频散曲线中特征频率与裂纹尺寸负相关.含几种不连续尺寸裂纹的岩体中其频散曲线呈"阶梯跳跃"形,其衰减曲线也有不同的峰值;而含"均匀分布"与"正态分布"裂纹尺寸的岩体,与含单一尺寸缺陷的岩体相比,其频散曲线具有较宽的特征频率段.结合两个声波测试实例,讨论了这一理论模型的合理性与可行性.

Scattering laws in rock mass which contained flat ellipse crack was researched. The Green function method was presented at mesoscopic scale; linear superposition idea was ap- plied into this model to get wave velocity dispersion and attenuation coefficient at macroscopic scale. The characteristic frequency in frequency dispersion curve is negative correlation with crack size. It had been discovered that a Ladder jump pattern could be presented in frequency dispersion curve ff rock mass contains discontinuous size crack, while its characteristic fre- quency region would be widened if the crack size continues to distribute, such as uniform dis- tribution or Gauss distribution. With two acoustic testsc combined, the rationality and feasibili- ty of this theoretic model is been discussed.