非贯通裂隙介质中波传播特性试验研究

 以研究非贯通裂隙对波传播的影响为主要目标，采用类岩石材料模型试件模拟节理裂隙介质，对不同裂隙长度、裂隙厚度、裂隙倾角、裂隙密度、裂隙形态(连续与非连续)的非贯通裂隙试件的声波特性进行超声波试验研究，测试和分析纵波在裂隙介质中的波速变化和振幅衰减规律。以国际大型的岩土工程分析程序FINAL为数值分析平台，进行与模型试验相对应的裂隙介质中的波传播数值仿真分析，对比分析纵波波速和波幅衰减的变化规律。研究结果表明，波速随裂隙长度变化很不明显；波幅的衰减取决于与波传播方向相垂直方向的裂隙水平投影长度，裂隙水平投影长度越大，波幅衰减量越大；随裂隙排数的增加，波幅发生衰减，2排裂隙试件的波幅值约为1排裂隙波幅值的1/2，3排裂隙试样的波幅值约为1排裂隙波幅值的1/3，且随裂隙增加，最大波幅值发生滞后现象。

EXPERIMENTAL STUDY ON CHARACTERISTICS OF WAVE PROPAGATION IN MEDIA CONTAINING INTERMITTENT CRACKS

To study the influence of intermittent cracks(joints) on wave propagation in fractured rock media，the rock-like material samples are adopted to simulate rock media with different lengths，thickness，densities，angles and forms of cracks. Supersonic tests on these samples are conducted to study the changes of velocity and amplitude attenuation of longitudinal wave in cracked media. Additionally，the corresponding numerical simulations are conducted to study the characteristics of wave propagation in cracked media with international large-scale geotechnical analysis software FINAL. The numerical results are compared with laboratory results. The research results show that crack length nearly has not influence on longitudinal wave velocity. Attenuation of stress wave amplitude depends on the projection length of cracks which are perpendicular to wave propagation direction. The larger the projected length of crack is，the more the wave amplitude attenuates. With the increasing rows of cracks，the stress wave amplitude will attenuate. The stress wave amplitude of sample with two rows of cracks is about half of that of sample with one row of cracks，and stress wave amplitude of sample with three rows of cracks is about one third of that of sample with one row of cracks. Furthermore，the largest stress wave amplitude will be delayed with the increasing rows of cracks.