单轴加载条件下煤岩超声各向异性特征实验  

An experimental study of ultrasonic anisotropy of coal under uniaxial loading

作　　者：赵宇[1] 张玉贵[2] 周俊义[2] 

机构地区：[1]河南理工大学土木工程学院,河南焦作454000 [2]河南理工大学安全科学与工程学院,河南焦作454000

出　　处：《物探与化探》2017年第2期306-310,共5页Geophysical and Geochemical Exploration

基　　金：国家科技重大专项"全国重点煤矿区瓦斯(煤层气)赋存规律和控制因素"(2011ZX05040-005);河南省科技攻关计划项目"煤体吸附膨胀变形各向异性特性实验研究"(162102310427)

摘　　要：在煤岩弹性波响应特征研究中,较少系统地考虑轴压对煤岩纵、横波速度和衰减的影响。基于此,选取平煤八矿3种不同变质程度煤样,制备垂直层理、平行层理垂直面割理和平行层理垂直端割理3类煤样,进行煤岩单轴应力作用下的超声测试。实验结果表明:(1)在自然状态下,3种变质程度煤样3个方向的纵、横波速度以及品质因子均存在各向异性,一般情况下平行层理的两个方向纵、横波速度以及品质因子均大于垂直层理方向;(2)煤岩的纵、横波速度随着轴压的增加呈现先快速增加,后缓慢增大,直至煤样破坏后波速迅速降低的阶段性变化规律,横波速度阶段性变化规律不如纵波明显;(3)3个方向品质因子都随着应力的增加呈现先增加后减小的变化趋势,且Q_s普遍比Q_p大;(4)不同变质程度煤样,纵、横波速度和品质因子差异均比较明显,1/3焦煤纵、横波速度大于焦煤大于肥煤。In the study of coal rock elastic wave response characteristics,the influence of axial compression on longitudinal wave,transverse wave velocity and attenuation has not been given enough comprehensive consideration. In view of such a situation,three kinds of coal samples which experienced different grades of metamorphism were chosen from the Pingdingshan No.8 mine.Vertical-bedding samples,parallel-bedding and vertical-face cleat samples,parallel-bedding and vertical-butt cleat samples were prepared to conduct water absorption and ultrasonic experiment. Some experimental results have been obtained： First,in the natural state,longitudinal,transverse wave velocity and quality factor in three directions of the three kinds of coal samples are anisotropic,generally longitudinal,transverse wave velocity and quality factor in two directions parallel to bedding are greater than the corresponding data perpendicular to bedding plane.Second,in the coal rock,the longitudinal and transverse wave velocity increases rapidly with the increase of axial pressure in the early stages.After that,the velocity increases slowly and the wave velocity decreases rapidly until the coal sample is destroyed,the transverse wave velocity is not as obvious as the longitudinal wave.Third,in the three directions,the quality factor increases firstly and then decreases with the increase of stress,and Q_S is generally larger than that of Q_P.Fourth,in coal samples of different metamorphic grades,longitudinal,transverse wave velocity and quality factor differences are more obvious,longitudinal,transverse wave velocity of 1/3 coke is greater than that of coking coal and that of the fat coal.

关 键 词：单轴加载 各向异性 弹性波速度 衰减 割理 

分 类 号：P631.4[天文地球—地质矿产勘探]