摘要
通过对不同岩性的岩石进行单轴压缩声发射试验,获取岩石破裂全过程中的载荷-轴向变形曲线及声发射参数,观察试件破裂失稳时的破坏情况,分析破坏过程的载荷变化关系。着重对比了不同岩石的不同力学性质、岩石声发射序列的时域特征和声发射序列的分形特征。研究结果表明,采用声发射率、能率可以很好地描述岩石破裂损伤的整个阶段;计算岩石声发射率、声发射能率的关联维数,可得出岩石破裂过程的声发射序列具有分形特征;岩石破裂过程的声发射分维值D反映了岩石内部微裂隙的统计演化规律;不同岩性的岩石破裂过程的声发射参数序列的分形特征具有一定的共性;归纳总结出岩体声发射序列分维曲线的演化模式,即波动→持续下降演化模式,提出可以将分维值的持续下降作为岩体破裂失稳的前兆。
Fractal dimension of AE （acoustic emission） serials of different types of rocks was investigated by uniaxial compression test. The complete stress-strain curves, the AE characteristics and the fracture patterns were obtained. The rupture instability specimens of destruction were observed; and the load change relationships of failure process were analyzed. Different mechanical properties, the AE sequence of time domain features and fractal feature of different rocks were researched emphatically. The results show that the AE rates ad AE energy rates can be very good to describe the collapse of the rock masses. The correlation dimension of the AE rates and AE energy rates during the progressive failure process has a strong characteristic of fractal feathers. The fractal dimension of AE sequences reflected the statistical evolution of the initiation and propagation of the microcracks in the rocks. The fractal dimension for all the specimens decreased when the loading stress increased. The evolutions of the fractal dimension of AE during failure can be divided into a mode for rocks. The fractal dimension for a mode of ＂fluctuation→gradual descending＂. The descent of the fractal dimension can be regarded as the precursor information to predict the collapse of the rock masses.
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2012年第12期3561-3569,共9页
Rock and Soil Mechanics
基金
国家自然基金(No.51079017
No.50804006
No.51174071)
教育部新世纪优秀人才计划(No.NECT-09-0258)
全国优秀博士论文专项资助(No.200860)
关键词
岩石力学
破裂失稳
声发射
分形
演化模式
rock mechanics
failure instability
acoustic emission （AE）
fractal
the mode of evolution
