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研究断层带几何非规则体对断层活动的力学影响,对于理解断层带上的地震活动具有重要的理论和实际意义.通过中尺度标本岩石力学实验,研究了走滑断层带最常见的一种非规则体-断层阶区对滑动行为的影响.研究表明,拉张断层阶区由于强度较低而很容易发生破裂,破裂后的阶区对断层的滑动无明显阻碍作用,但阶区的微破裂对断层滑动失稳具有指示作用;含拉张阶区的断层带具有速度弱化特征,可用速率-状态摩擦定律表述.挤压阶区由于破坏强度很高,使得断层滑动较为困难,但随着应力水平的增加,阶区外断层端部拉张区的微破裂为断层在阶区未破裂之前发生粘滑失稳提供了变位条件,并因此可作为断层失稳的前兆;挤压阶区可作为断层分段的稳定标志,直到阶区完全破裂使两条断层完全连通.
Studying the mechanical influence of fault zone geometric irregularity on fault activity has important theoretical and practical significance for understanding seismic activity on fault zone.By means of rock mechanics experiment of mesoscale specimens, The results show that the fractured zone is prone to rupture due to the low strength, and the fractured zone has no obvious hindrance to the slip of the fault, but the micro-rupture Which can be used to indicate the slip failure of faults. The fault zones with tension zones have the characteristics of velocity weakening, which can be described by the rate-state friction law. Because of the high failure strength, the fault slip is difficult, but with the stress As the horizontal increase, the micro-fracture in the tension zone at the end of the out-of-step fault provides the displacement condition for the slip-slip instability of the fault before the fault does not collapse, and thus can be used as a precursor to the fault failure. As a stable mark of the fault section, the two faults are completely connected until the stage completely ruptures.