ACOUSTIC EMISSION CHARACTERISTICS OF GRANITE UNDER TENSILE LOADING
LI Tianyi1，2，LIU Jianfeng1，2，CHEN Liang3，XU Jin1，2，WANG Lu1，2
(1. State Key Laboratory of Hydraulics and Mountain River Engineering，Sichuan University，Chengdu，Sichuan 610065，China；2. Key Laboratory of Energy Engineering，Safety and Mechanics on Disasters，Ministry of Education，Sichuan University，Chengdu，Sichuan 610065，China；3. Beijing Research Institute of Uranium Geology，Institute of Environmental Engineering，
Beijing 100029，China)
摘要利用MTS815 Flex Test GT岩石力学试验系统和PCI–2声发射(AE)三维定位系统，对甘肃北山花岗岩在直接拉伸和间接拉伸试验条件下的强度、变形及其破坏全过程的声发射特征进行研究。试验结果表明：直接拉伸得到的抗拉强度的平均值、最大值和最小值均分别高于间接拉伸，且前者峰值应力时的应变量小于后者，约为后者的6.03%；直接拉伸试验加载开始至40%峰值应力阶段，声发射较为平静，此后声发射计数和能量均开始增加，接近峰值应力时，声发射事件数达到最大；间接拉伸试验整个破坏过程的声发射计数率基本持平，但40%峰值应力前的初期加载阶段的声发射能率高于40%峰值应力后；间接拉伸过程中，试件受压缩应力及加载接触部位屈服破坏的影响，能量释放量高于直接拉伸。
Abstract：The granite samples from Beishan of Gansu Province were tested on MTS815 Flex Test GT rock mechanics test system，including direct tensile test and indirect tensile test. The mechanical behaviors of granite were studied，and the acoustic emission(AE) was monitored by PCI–2 system. The test results showed that：the average value，the maximum and minimum values of tensile strength in direct tensile tests were greater than indirect tensile tests；the tensile strain of direct tensile tests was 6.03% of that of indirect tensile tests at the peak stress. Few AE signals were monitored for direct tensile tests before the loading stress was below 40% of the peak stress. When the loading stress was larger than 40% of the peak stress，AE counts and AE energy all increased. Especially，when it was close to the peak stress，AE events were the largest. For indirect tensile tests，the AE count rate during the full process was almost similar，and the energy release ratio at initial loading stage，e.g. less than 40% of the peak stress，was larger than the latter loading stage. Due to the effect of loading mode，the energy release ratio for indirect tensile tests was larger than that for direct tensile during the full failure process.
邓广哲，王广地. 北山花岗岩热黏弹性流变特性分析[J]. 岩石力学与工程学报，2004，23(增1)：4 368-4 372.(DENG Guangzhe，WANG Guangdi. Analysis of characteristics of thermo-viscoelasto rheology of Beishan granite[J]. Chinese Journal of Rock Mechanics and Engineering，2004，23(Supp.1)：4 368-4 372.(in Chinese))
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2013, Vol. 32 
