基于声发射监测循环载荷下岩石损伤过程

Rock Damage Process Based on Acoustic Emission Monitoring Under Cyclic Loading

应用声发射技术对循环载荷下岩石损伤过程进行了实验研究.基于加卸载响应比理论和损伤力学理论建立了循环载荷下岩石破坏过程中的内部损伤和声发射关系的数学模型,分析了循环加载方式下的岩石损伤演化过程和岩石失稳破坏的前兆.实验结果表明,岩石加载的声发射活动规律反映了其损伤过程;在循环加载条件下,随着载荷的增加,岩石在卸载过程中的损伤逐步增大,声发射数加卸载响应比Y值逐渐减小;对于大多数岩石试样而言,在其处于弹性变形后期时,声发射数加卸载响应比Y值达到(或接近)1并在小范围内波动,可以作为岩石失稳破坏的前兆,这对于循环载荷下岩石失稳破坏具有预测意义.

Experimental studies on rock damage process based on acoustic emission（AE） technique were carried out under cyclic loading.On the basis of damage theory and load/unload response ratio theory,a mathematical model of the relationship between rock damage and AE numbers was established to study the rock damage process and the precursor of rock failure.The results showed that acoustic emission principles can reflect the rock damage process.Under cyclic loading,rock damage increases with stress level during the unload phase,but the Y value of acoustic emission load/unload ratio decreases gradually.For most rock specimens,the Y value reaches 1 and fluctuates in a small range when rocks reach the later phase of elastic deformation,which can be seen as a precursory characteristic to rock failure and this is meaningful to the forecasting of rock unstable failure under cyclic loading.