冻融温度区间对砂岩声发射特性的影响

为探究冻融作用对砂岩物理力学特性及内部破裂损伤规律的影响,对砂岩开展不同温度区间的冻融循环试验,并对冻融损伤岩石进行单轴加载作用的声发射试验,研究冻融温度区间对岩石物理力学参数及声发射特性的影响。结果表明：随着冻融循环温度区间增长,质量损失率和纵波波速变化率整体上呈先陡后缓的上升趋势,砂岩的峰值强度不断下降且峰值应变逐渐增加,单轴抗压强度和弹性模量逐渐减小,且同一冻融温度区间对弹性模量的影响较单轴抗压强度更为显著,泊松比呈现逐渐增长趋势;声发射振铃计数及累计振铃计数呈现逐渐增长趋势,沉寂期变小,声发射分布时间范围减小,峰值频率呈现向低频发展趋势。研究成果为寒区岩体工程稳定性预测提供实验依据。

Effect of Freeze-thaw Temperature Range on the Acoustic Emission Properties of Sandstone

In order to investigate the effects of freeze-thaw action on physical and mechanical properties and internal fracture damage of sandstone, freeze-thaw cycle tests were carried out on sandstone at different temperature range, and acoustic emission tests were carried out on freeze-thaw damaged rocks under uniaxial loading, so as to study the influence of freeze-thaw temperature range on physical and mechanical parameters and acoustic emission characteristics of rock. The results show that the temperature range increases with the freeze-thaw cycle, the mass loss rate and the change rate of p-wave velocity on the whole show a trend of first steep and then slowly rising, declining peak intensity and peak strain of the sandstone gradually increase, the uniaxial compressive strength and elastic modulus decreases, and the same freezing and thawing temperature range of the influence of elastic modulus under uniaxial compressive strength is more significant, and Poisson"s ratio shows a trend of gradual increase. With the increase of freeze-thaw temperature range, the acoustic emission ringing count showed a gradual increasing trend, the cumulative ringing count gradually steepened, the silence period became smaller, the acoustic emission distribution time range gradually decreased, and the peak frequency showed a trend of low frequency development. The research results provide experimental basis for predicting engineering stability of rock mass in cold area.