中文摘要：

为了研究实验变形失稳过程中的应变场快速调整阶段和岩石结构破坏过程中的复杂变形场,将高速、高分辨率、多通道的应变观测技术引入构造物理实验,搭建了用以观测瞬态变形场的多通道动态应变观测系统,形成了16Bit分辨率、96通道、3.4kHz采样速度、1με分辨率且连续记录的应变观测系统.通过观测断层失稳过程高速滑动阶段和裂纹扩展过程的力学场时空变化,发现断层粘滑失稳过程的演化具有3个特征阶段：预滑动阶段、高频震荡阶段和低频调整止滑阶段.每个阶段的持续时间、应变速率、频率特性、振幅等都具有自身特点;三维断层扩展模型的实验结果显示,岩桥区断层贯通是一个快速过程,先多点局部扩展,后跳跃式连接.在断层贯通之后,样品整体崩垮之前,存在一个相对稳定的阶段,持续时间为几十ms.多通道动态应变观测系统填补了在地震模拟与岩石力学实验中应变观测频带的空缺,可以获得高密度、高精度的动态应变场,进一步研究瞬态应变场演化与应变波时空过程,为理解从缓慢递进变形到突发失稳释放过程提供了技术支持.

英文摘要：

In order to study the complex strain field during the instability process of rapid deformation adjustment stage and the rock failure process in rock experiments,high-speed,high-resolution,multi-channel strain observation technology is applied to physical simulation experiment and developed as Multi-channel Dynamic Strain Observation System for monitoring the transient deformation field.The specially designed system has 96 channels with a sampling rate up to 3,400 samples/s/ch,and a resolution of less than 1με （micro strain）and continuous recording.We found some important phenomena by observing the temporal and spatial variation during the fault instability process and crack propagation process.The experiment on three typical stick-slip models shows that the evolution of the unstable fault stick-slip process has a relatively stable feature characterized by three typical phases （precursory slip,rapid slip incorporated with high-frequency strain vibration and terminal adjustment）.Each phase has its own characteristics of duration,strain rate,frequency,amplitude and energy.The experimental results on the three-dimensional fault propagation model show that the coalescence of the bridge area occurs at the last stage and is a rapid process.The crack initiation occurs at several points which combine each other randomly.There is a stable period existing between the full propagation and coalescence and sample failure,and the duration time is several tens milliseconds.Multi-channel dynamic strain observation system fills the band gap of strain observation in rock mechanics experiments and earthquake simulation experiments.High-density and high-precision strain data can be obtained by this system,which can further promote the studies on the transient strain field evolution and the temporal and spatial process of strain wave and provide technical support for understanding the process from a slowly progressive deformation releasing to the sudden instability.