循环荷载下红砂岩损伤破坏过程次声波特征

The Infrasound Characteristics in the Damage and Failure Process of Red Sandstone under Cyclic Loading

为研究岩石损伤破坏过程中次声波信号特征,对红砂岩进行单轴循环加、卸载次声波试验,分析了岩石加、卸载过程中次声幅值和累计振铃计数等参数特征,在此基础上,对比分析基于耗散能法和次声波法表征岩石损伤破坏演化过程特征。研究结果表明,单轴循环加、卸载条件下,红砂岩的次声信号活动可描述为相对稳定期、活跃期和破坏前兆期3个阶段;用次声波累计振铃计数可较好的反映红砂岩内部损伤演化过程,加载与卸载阶段都会产生损伤,且损伤随应力的增大而增大。峰值应力前,次声幅值变化相对平缓,累计振铃计数增量并不明显,但仍有大量的次声信号产生。

In order to study the infrasound characteristics in the rock damage and failure process,infrasound experiments of red sandstone under uniaxial cyclic loading and unloading were carried out.And the characteristics of amplitude and accumulative count were analyzed.On this basis,the characteristics of rock damage and failure process were compared and analyzed based on the dissipative energy method and the infrasonic wave method.The results showed that under uniaxial cyclic loading and unloading,the infrasound signal activity of red sandstone had three phases including relatively stable phase,active phase and failure precursor phase.The accumulated count could well reflect the internal damage process of red sandstone.The damage would occur in loading and unloading phase,and increased with the increase of stress.Before reaching the peak stress,the change of infrasound amplitude was relatively stable,the increment of accumulative counts was not obvious,but a lot of infrasound still generated.