砂岩单轴循环加卸载过程中声发射信号特征与时空演化规律

为深入研究循环荷载作用下岩石内部微裂纹萌生、发展及贯通的时空演化规律,以砂岩为研究对象,开展了砂岩在单轴循环加卸载下的声发射试验。结果表明:借助不同方向的波速测试,可获得声波在岩石中的传播速度,为声发射定位提供合理的波速参数;通过合理布置传感器的位置,可准确定位破裂面的空间位置;加卸载过程中声发射事件数和能量呈现台阶状上升,表明声发射具有记忆效应;通过声发射事件空间定位与破坏岩样的对比,验证了两者的位置基本一致,表明声发射可有效获得岩石内部微裂纹发展的全过程。

Characteristics of acoustic emission signals and spatiotemporal evolution law in the process of uniaxial cyclic loading and unloading process of sandstone

In order to reveal the spatiotemporal evolution regularities of the internal microcracks initiation, development and coalescence in rock under cycling loading, using sandstone as the research object, the acoustic emission tests of sandstone in uniaxial cyclic loading and unloading were carried out. The results show that: the propagation velocity of sound wave in rock can be obtained by the wave velocity test in different directions, which can provide reasonable velocity parameters for acoustic emission location; the space position of fracture plane can be accurately located by reasonably arranging the position of the sensor; the number of acoustic emission events and energy present a stepwise increase during the loading and unloading process, indicating that acoustic emission has memory effect; through the comparison between the space location of acoustic emission events and position of rupture surface in the rock sample, two positions are basically the same and the acoustic emission can effectively obtain the whole process of rock crack propagation. The results can provide important technical support for the rock mass stability analysis, which has an important value of engineering application.