岩石摩擦滑动变形演化及声发射特征研究

进行岩石摩擦滑动变形演化过程的声发射特征试验研究。以数字散斑相关方法和声发射系统为试验监测手段，采用双面剪切模型试验方法，开展界面摩擦滑动速率与声发射振铃计数、界面摩擦滑动位移与声发射累计能量、试件变形能密度与声发射b值的对应关系研究。结果表明：（1）声发射振铃计数演化受岩石界面摩擦滑动速率影响，界面摩擦滑动速率的突变与声发射振铃计数激增有较好对应关系；（2）界面摩擦滑动位移与摩擦滑动过程中声发射累计能量演化趋势具有较好的对应关系，可以利用声发射累计能量对岩石摩擦滑动位移的变化趋势进行定性判断；（3）通过声发射b值演化分析可以得出，在剪应力缓慢增长阶段，界面摩擦滑动以随机分布的小尺度微破裂为主；在剪应力线性增长阶段后期，界面摩擦滑动以锁固段的大尺度微破裂为主；在剪应力波动增长阶段，岩石摩擦滑动失稳既可能是由小尺度微破裂为主引发的状态转化，又可能是由以锁固段大尺度微破裂为主引发的稳定状态转换。

Study of acoustic emission characteristics and deformation evolution during rock frictional sliding

The acoustic emission characteristics of deformation evolution during rock frictional sliding is studied in the present work. Digital speckle correlation method and acoustic emission system were adopted to measure deformation and AE information in the experiment process. The corresponding relationship between the interface frictional sliding rate and the acoustic emission ringing count, the interface frictional sliding displacement and the acoustic emission cumulative energy, the specimen deformation energy density and the AE b-value were studied. The results show that: the evolution of acoustic emission ringing count was influenced by frictional sliding rate of rock interface. There was a close correlation between the sudden change of acoustic emission ringing count and surge of rock interface frictional sliding rate. The acoustic emission cumulative energy was related to the frictional sliding displacement of rock interface. The change trend of frictional sliding displacement of rock interface could be qualitatively identified by the evolution characteristics of the acoustic emission cumulative energy. Based on the evolution characteristics of AE b-values, the interface frictional sliding was dominated by small-scale microcracks of random distribution during the period of slowly increasing shear stress, while the interface frictional sliding was dominated by large-scale microcracks of locking area during the period of shear stress linear growth stage late. The failure of rocks frictional sliding might be caused by small-scale microcracks, and might be also caused by large-scale microcracks of locking area during the fluctuation process of shear stress.