摘要
应用声发射及其定位技术,采用实验手段研究了不同加载方式(单轴加载、巴西劈裂及三点弯曲条件下)不同尺寸岩石以及不同岩样破裂失稳过程。实验结果表明,在岩石弹性变形阶段,声发射事件定位位置为岩样内部的应力集中位置;随着加载的进行,声发射仪器精确地定位出其裂纹初始位置、扩展方向,并直观地反映出其内部裂纹稳定扩展过程。从巴西劈裂实验的声发射事件定位结果可以看出,初始裂纹产生的位置具有随机特性,且初始裂纹产生是诱发岩石破裂失稳的首要因素。岩样尺寸影响其破坏模式,受加载过程裂纹初始时序不同影响其声发射活动规律表现不一致;不同岩样声发射活动随应力变化呈一定的规律性,其中砂岩在加载过程其声发射活动具有突跳特性,这主要与岩石均质程度相关。声发射定位结果直观地反映岩样内部裂纹初始、扩展的空间位置,这对于深入研究岩石破裂失稳机制具有一定的意义。
Acoustic emission（AE） and its location technique are utilized to study the failure process of different sized rock samples under different loading conditions（uniaxial loading, Brazilian splitting testing and three-point bending loading）. From experimental results, the position of AE events corresponds to the position of stress concentration during the elastic loading step. With the increase of external loading, AE instrument can exactly locate the position of crack initiation and propagation： and AE location events can reflect the stable crack propagation process. The AE location result of Brazilian splitting testing indicates that, the position of initial crack is generated randomly, and the initial crack is the primary factor inducing rock instability. The failure modes of rock samples are varied by the sizes of granite samples. The AE activity is influenced by crack generation during loading process; by contrast, the AE activity is different for various rock samples as well. The AE activity of granite sample shows stress jump, but few AE events are generated during initial loading processing and elastic loading period of sandstone. The AE events increase abruptly with the external loading, which is related to the characteristics of rock components. AE location results also directly reflect the spatial position, direction and spatial curved face of crack propagation in the rock samples, which provides very significant evidences for the study of rock failure mechanism.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2008年第5期990-995,共6页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(50574022,50674025,50504005)
国家重大技术研究发展规划项目(2007CB209405)
关键词
岩石力学
声发射
岩石破裂过程
巴西实验
单轴加载
rock mechanics
acoustic emission
rock failure process
Brazilian testing
uniaxial loading
作者简介
赵兴东（1975-），男，博士，1997年毕业于焦作工学院矿井建设专业，现任讲师，主要从事岩石破裂失稳与控制方面的教学与研究工作。E-mail：zhaoxingdong@mail．neu.edu．cn
