Abstract: This work elucidates the stability boundary for small perturbation and dynamic motion of an inclined spring slider fault system in which normal stress is coupled to shear stress on the sliding surface. With rate and state dependent friction,our anlysis shows that critical stiffness on the stability boundary decreases with increase of sliding rate. This means that a positive jump of the load point velocity may lead to a transition from cyclic stick slip motion to stable sliding; and a decrease of the load point velocity may lead to a transition from stable sliding to cyclic stick slip motion. Positive velocity jump greater than a certain amount may also trigger a single instability,but no transition between cyclic stick slip and stable sliding modes occurs in this situation. Experimental evidences of triaxial friction tests from references and our own experimental study support these theoretical results.

Key words: Fault displacement rate, Numerical simulation, Critical stiffness, Sliding stability

摘要： 在与主压应力方向斜交的断层上,正应力与剪应力之间存在线性相关关系,以此为基础导出了小扰动条件下决定稳定性的临界刚度与滑动速率的关系。由于这一关系具有临界刚度随滑动速率增加而减小的特点,因此速率增加可能导致周期性粘滑向稳定滑动转化,而速率减小可能使本来稳定的滑动转化为周期性粘滑过程。在这种斜交断层中,速率增加虽然可能抑制周期性粘滑,但是稳滑时超过一定限度的速率增加会导致一次性不稳定滑动。三轴摩擦实验提供了关于粘滑与稳滑可相互转化的支持证据。

关键词: 断层位移速率, 数值模拟, 临界刚度, 滑动稳定性