Transition from Uniform Motion to Stick-Slip in the Rice-Ruina Model of One and Two Blocks

We analyze the Rice-Ruina state and rate dependent friction model. The system consists of one or two blocks driven by springs with constant velocity on a dry, rough surface. Our discussion is limited to the creep-like motion, when the driving velocity is small. Two regimes of motion are observed: stick-slip and steady sliding. The stability of the steady sliding depends on the model parameters. Numerical and analytical results show a transition between two regimes: the system passes directly from uniform to stick-slip motion. The calculations are performed also for two driven blocks. Then, the transition has the same character and it appears at the same point.