加载速率对砂岩和花岗岩声发射事件宏微观形成机制的影响  

Influence of loading rate on macro and micro formation mechanism of acoustic emission events in sandstone and granite

作　　者：冯小静[1] 张睿哲 FENG Xiaojing;ZHANG Ruizhe(College of Mining Engineering,Taiyuan University of Technology,Taiyuan 030024,China)

机构地区：[1]太原理工大学矿业工程学院,山西太原030024

出　　处：《煤矿安全》2021年第5期47-53,共7页Safety in Coal Mines

基　　金：国家自然科学基金资助项目(51604184,51304143);国家重点基础研究发展计划(973计划)资助项目(2014CB047100)。

摘　　要：分析了砂岩、花岗岩在不同加载速率下声发射事件的分布特征,并对有、无声发射事件区域的岩石碎片进行电镜扫描,从宏微观并结合声发射信号特征分析了加载速率对声发射事件形成机制的影响。研究表明:随加载速率的增加,镜面区特征逐渐减弱,即其对应的颗粒间的滑移以及岩石内部微裂隙共同作用产生的破坏变少,同时岩石越易发生脆性破坏,其产生的声发射信号多为连续型(或似连续型),不利于形成声发射事件,所以声发射事件数逐渐变少;对于砂岩,微破坏及小的宏观破坏是声发射事件形成的根源,对于花岗岩,颗粒间的位错是声发射事件形成的根源;花岗岩镜面区特征及范围较砂岩明显,即颗粒间的滑移及微裂隙共同作用更加明显,同时宏观上砂岩的破碎程度和规模也远小于花岗岩,所以砂岩的声发射事件数远少于花岗岩;镜面区特征明显说明颗粒间的滑移以及岩石内部微破坏是岩石的主要破坏组成,所以花岗岩从加载开始便有声发射事件,而砂岩没有。砂岩和花岗岩声发射事件的形成机制有着明显的区别。The distribution characteristics of acoustic emission events of sandstone and granite at different loading rates are analyzed.Electron microscopy of rock fragments with and without acoustic emission events is performed.The effects of loading rate on the formation mechanism of acoustic emission events are analyzed from macroscopic and microscopic combined with acoustic emission signal characteristics.The results show that with the increase of loading rate,the characteristics of the mirror area are gradually weakened,that is,the slip between the corresponding particles and the micro-cracks in the rock become less,and the more likely the rock is brittle,the more the acoustic emission signals are mostly continuous(or quasi-continuous),which is not conducive to the formation of acoustic emission events,so the number of acoustic emission events is gradually reduced.For sandstone,micro-destruction and small macroscopic damage are the root causes of acoustic emission events.For granite,dislocations between particles are the source of acoustic emission events.The characteristics and range of granite mirror area are more obvious than that of sandstone,that is,the slip and micro-fracture interaction between particles is more obvious.At the same time,the fracture degree and scale of macroscopic sandstone are much smaller than that of granite,so the number of acoustic emission events of sandstone is much less than that of granite.The characteristics of the mirror area clearly indicate that the slip between particles and the micro-destruction inside the rock are the main failure components of the rock,so the granite has an acoustic emission event from the beginning of loading,but the sandstone does not.There are obvious differences in the formation mechanism of acoustic emission events between sandstone and granite.

关 键 词：加载速率 声发射事件 电镜扫描 宏观机制 微观机制 

分 类 号：TD313[矿业工程—矿井建设]