常温下花岗岩受力热红外光谱变化与敏感响应波段

Stress-related thermal infrared spectral variation and sensitive waveband of granite

通过对两种花岗岩进行室内常温下单轴压缩加载,利用热红外光谱辐射计(8～14μm)对加载过程中试样的热红外光谱辐射进行观测,研究岩石受力过程热红外光谱变化特征,揭示其应力敏感波段.结果表明,花岗岩辐射亮度(增量)与应力呈线性关系,矿物组分及结构差异对应力敏感波段有重要影响.按红外光谱辐射亮度与载荷的相关系数、拟合直线最大变幅-标准偏差比两项指标进行综合分析,揭示富含钾长石的斑状花岗岩的应力敏感段为8.4～10.6μm,中心波长为8.75μm;富含斜长石的等粒花岗岩的应力敏感波段为8.2～11.7μm,中心波长为10.25μm.上述波段可分别作为相应花岗岩的应力与灾变红外遥感监测的优势波段.

This paper studied the variation of the stress-related thermal infrared spectrum of the rock under pressure. The thermal infrared spectrum radiation from two kinds of granites under uniaxial compression at room temperature was moni- tored with a spectroradiometer （8 - 14 μm）. The experimental results show that the infrared radiance （amount of in- crease） of rock varies linearly with the stress. The stress sensitive waveband is determined by the mineral component and structures of the rock. The correlation coefficient between infrared radiance and load was analyzed comprehensively, so was the ratio of maximal variation to standard deviation. The results show that sensitive waveband to stress is in the range of 8.4 - 10.6μ m for rich-feldspar porphyritic granite with central band at 8.75 μm; while for rich-plagioclase and equigranular granite, the sensitive waveband to stress is 8.2 - 11.7 μm, and centered at 10.25 μm. These wavebands can be used as reference for monitoring of the stress and catastrophe of the rock with infrared remote sensing.