不同应力路径对岩石声发射Kaiser效应的影响

为了解在循环加载过程中使用不同应力路径岩石声发射Kaiser效应的特征,采用岩石破裂过程分析软件(RFPA2D)对三种不同应力路径下岩石试样的声发射特征进行了数值计算.在循环加载中采用不同的应力路径对试样加载,在二次加载过程中仍能观测到清晰的Kaiser效应,但是KF值却与先前的最大应力值有较大差别.研究结果表明,岩石Kaiser记忆的真实内容不是先前所受的最大应力,而是岩石内部的损伤程度.使用从原岩中取样,在实验室做单轴压缩声发射实验观测KF值的方法测得的应力值与真实的原岩应力有较大的差别.这一结论对于进一步认识Kaiser效应的本质和用Kaiser效应准确的测定原岩应力有重要的作用.

Effect of Different Stress Paths on Kaiser Effect of Rock Acoustic Emission

To understand the characteristic of Kaiser effect along different stress paths during cyclic load acting on rock,a numerical computation was conducted using the software RFPA2D(Rock Failure Process Analysis) for the characteristics of AE(acoustic emission) along three different stress paths in rock specimens.The results showed that the Kaiser effect is still clearly observed in the subsequent cycle when the specimens are under the action of cyclically loading though a big difference between KF values(the stress value at Kaiser effect point) and previous max stress value is found.It was revealed that what was actually recorded in the Kaiser effect memory is the damage level within rock other than the max stress acting previously on the specimens.So,if sampling from parent rock, the stress value measured from observing KF value by uniaxial compression AE testing in lab is different greatly from that in parent rock.The conclusion is significant to understanding the essence of Kaiser effect and how to use it to determine the in-situ stress.