为研究构造活动及其失稳过程的红外异常特征,选择拐折非连通断层作为模拟对象,利用单轴加载试验系统和红外热像仪,对模型受力及失稳过程的热辐射时空演化特征进行试验研究。结果表明:(1)随着应力的增高及阶段性变化,热像首先在下部断层出现1个高温异常点,强度逐渐增强,临近失稳前在岩桥端部又出现2个高温异常点,并具有交替出现的特征,最终演化为一热条带,继而断层连通失稳。"三点高温"和"交替演化"的红外辐射异常特征,与断层预滑、岩桥区应力集中及迁移有因果关系;(2)岩桥区的平均红外辐射温度(AIRT)在断层活动过程中呈现3个阶段的变化特征,表现为低应力阶段的基本不变或变化很小、中间应力阶段的缓慢上升和临失稳阶段的加速上升。AIRT短暂降温之后的加速上升是断层破裂失稳的重要前兆;(3)断层周围不同区域的AIRT变化特征不同,与不同区域应力性质差异存在密切关系。应力、应变、红外辐射等多参数的对地集成观测是未来构造活动及其灾变分析的关键。
To study the infrared anomaly features of tectonic activity and process of instability,the tortuously non-connected fault is selected as a physical simulation model,and the thermal infrared radiation(TIR) variation features of fault models are experimentally studied in the process of loading and instability by means of uniaxial loading system and TIR imaging system.It is revealed that:(1) with the stress increases periodically,a high-temperature anomaly point firstly appeared at the lower fault,and the temperature of the point gradually increases.When the fault is close to destabilization,two new high-temperature anomaly points appear alternately at the end of the rock bridge,and finally become a hot strip.Then two faults connect and are destabilized.There is a causality of the infrared radiation(IRR) anomaly feature of three high-temperature points and alternating evolution with the pre-sliding of fault,the stress concentration in the region of rock bridge and migration;(2) the average infrared radiation temperature(AIRT) of rock bridge region shows three-stage variation features manifested as AIRT is hardly changed at the low-stress stage,then increased slowly at the middle-stress stage and increased quickly at the instability stage.The rapid rise of AIRT after a short drop is an important precursor of fracture and instability;and(3) the difference of infrared radiation variation in different position is closely related to the stress property of different position.The united earth observation of multi-parameters,such as stress,strain and infrared radiation etc.,would be the key of analysis on tectonic activity and its disaster in the future.