岩石蠕变过程中声发射活动的实验研究

在常温下、单轴加压下对两种岩石完整样品进行蠕变破坏过程中声发射活动实验.根据实验获得的数据讨论了蠕变三个阶段中声发射活动特征.在瞬态蠕变阶段,随着加载,声发射活动逐渐增强;在稳态蠕变阶段,在较低的声发射活动背景上,可能出现较强的信号,声发射幅值-频度关系的 m 值可能稳定于某一低值,也可能下降;进入加速蠕变阶段,声发射活动水平增强,m 值下降加快,也可能表现为明显回升后再下降,并与岩石样品的性质有关.将蠕变破坏三个阶段中声发射活动与地震孕育过程中某些地震活动图象变化(如 b 值、前震活动)进行了联系,提出地壳岩石蠕变破坏机制形成前震——主震——(余震)型地震序列类型的可能性. 

THE EXPERIMENTAL STUDY OF ACOUSTIC EMISSION DURING CREEP OF ROCKS

Under normal temperature, uniaxial compression, creep experiments with whole samples of Gabbro and Marble rocks are made. According to the data obtained by tests, AE activities during three stage of creeping process are discussed. At the stage of instantaneous creep, AE events increase slowly with loading for samples; at the steady creeping stage, large AE signals appear probably on a lower background of AE action; the m-value which discribes the relationship between AE amplitude and frequency remains stable and at a low value or decreases. At the accelerated creeping stage, AE activities increase and the m-value decreases quickly or decreases again after recovery. These experimental results are related to the quality of rock samples.The AE activities during the three stages of creeping and fracture process are compared with the seismic patterns (for example ?value, foreshocks) during the seismogeny of a strong earthquake. Finally, it is pointed out that possibly the mechanism of creep fracture of crus-tal rocks forms the foreshock-mainshock-aftershock earthquake sequence.