不同应力水平下红砂岩短时蠕变声发射特征

为认识岩石蠕变过程中的声发射特征,进行了短时蠕变声发射试验,研究了红砂岩在不同应力水平下的声发射特征.试验结果表明:在减速蠕变至等速蠕变过程中,声发射事件率与能率随时间的增大而减小,并且减小的幅度随着应力水平的增大而减小;当加载应力约为峰值应力的40%~60%时,声发射振幅随时间的增大而减小;当加载应力约为峰值应力的70%~80%时,声发射振幅保持相对稳定.在加速蠕变阶段,声发射振幅发生跃迁的频率显著增大,而声发射事件率与能率在加速蠕变的中后期开始增大.因此,可根据不同应力水平下的声发射特征,对红砂岩不同蠕变阶段进行辨别.

Acoustic Emission Characteristics During Short-Time Creep Process of Red Sandstone Under Different Stress LeVel

The characteristics of acoustic emission (AE) of the red sandstone during short-time creep were studied under different stress level. The results show that the AE event ratios and energy ratios decrease with time increase during the period from decelerated creep to steady creep， and the corresponding reductions in amplitude decrease with the increasing stress level. The AE amplitude decreases and keeps relatively stable when the stress is about 40%~60% and 70%~80% of peak stress， respectively. The AE amplitude transition frequency increases obviously during the accelerated creep stage， and its event ratio and energy ratio begin to increase in the mid-late stage of accelerated creep. Therefore， the creep stage of red sandstone can be distinguished by the AE characteristics.