水对花岗岩受力灾变声发射主频特性的影响

Experimental Study on the Effect of Water on the Main Freqency Characteristics of Acoustic Emission of Granite

通过对干燥、自然、饱和3种状态下的花岗岩进行单轴压缩试验,并对加载过程中的声发射信号进行同步监测,分析了3种不同含水状态下岩石受力灾变的声发射信号主频变化特征,结果表明:不同含水条件下花岗岩加载至破裂全过程的声发射信号主频区间为0~110kHz,绝大部分信号的主频值集中在35~65kHz及15~25kHz频带区间;花岗岩加载过程的声发射主频演化可分为3个阶段,水会对各个阶段的声发射信号主频特性产生不同的影响;岩石失稳破裂前,声发射主频值由密集分布转向稀疏分布,35~65kHz的主频数量骤减,超低频值及高频值开始大量出现,可以认为是岩石受力灾变的前兆信息。

The uniaxial compression tests were carried out on the granites under dry, natural and saturated states, and the acoustic emission signals during the loading were monitored synchronously. The main frequency characteristics of acoustic emission signals of rock under different water-bearing states were analyzed. The results showed that, the interval of the main frequency of acoustic emission signal was 0-110 kHz for the whole loading process of granite until rupture under different water conditions, and for most of the signals, their main frequencies concentrated in the range of 35-65 kHz and 15-25 kHz. The acoustic emission frequency evolution in the granite loading process could be divided into three stages, and water would have different effects on the main frequency characteristics of the acoustic emission signals at each stage. Before the rock fracture, the main frequency of the acoustic emission shifted from the dense distribution to the sparse distribution, the number of 35-65 kHz frequency plummeted, and ultra-low frequency and high frequency began to appear in large numbers, which could be considered as a precursor to the rock disaster.