遥感-岩石力学(VIII)——论岩石破裂的热红外前兆

REMOTE SENSING-ROCK MECHANICS (VIII)—— TIR OMENS OF ROCK FRACTURING

岩石破裂存在多种前兆,它是岩石力学和岩石工程中的一项重要研究内容。在总结多年遥感-岩石力学基础实验研究的基础上,对岩石破裂的热红外前兆进行了系统总结与分析,包括:前兆表现形式及其类型、前兆的时间及空间特征、前兆的机理等。研究表明:(1) 岩石破裂的热红外前兆有平均红外幅射温度-时间曲线异常和热像异常2种形式,分别反映前兆的时空特征;(2) 热像异常分为高温条带和低温条带两种类型,平均红外幅射温度-时间曲线异常分为降温、升温加速和降温转升3种类型;(3) 前兆出现在岩石载荷峰前s = (0.77～0.87)sp 的应力区间内,与微破裂带的形成密切相关;(4) 高围压和压性强的剪性破裂出现前兆的几率要大于低围压和压性弱的剪性破裂,而随着破裂向纯剪过渡,前兆出现的几率降低,且前兆发生的时间越接近岩石破裂时刻;(5) 岩石破裂热红外前兆机理是岩石热弹和摩擦热效应的综合。

There are many omens existing before rock fracturing,which is an important research issue of rock mechanics and rock engineering. Based on the fundamental experiments on remote sensing-rock mechanics,the thermal infrared radiation (TIR) omens of rock fracturing are systematically analyzed and studied. The research contents of this paper include the types and features of TIR omens,the occurring time of TIR omens,the spatio-temporal features of TIR omens,and its mechanism. It is concluded that (1) there are two kinds of TIR omens for rock fracturing,i.e.,TIR image anomaly and curve of average TIR temperature and time anomaly,which reflect the spatial and temporal features of TIR omens respectively,(2) the TIR image anomaly is classified as high-temperature strip and low-temperature strip,and the curve of average TIR temperature and time anomaly is classified as temperature drop,rapid rise of temperature and rise-from-drop of temperature,(3) the omens occur before peak load at the moment when load is 77%～87% of the peak load,and they are tightly related to the formation of micro-cracks,(4) the possibility of omens of shearing fracturing with high confining pressure or high compressive stress is higher than that with low confining pressure or low compressive stress,and the possibility of omens for pure-shear will be less and its occurring time is close to the fracturing moment,and (5) the mechanism for the TIR omens of rock fracturing is the comprehensive effect of rock thermo-elasticity and rock friction.