EFFECTS OF FLOW RATE ON FRICTION SLOPE OF DEBRIS FLOW WITH ROTATING FLUME TESTS

This paper uses a newly developed rotating flume experiment apparatus. The friction slope and flowing rate of the debris flow are measured to evaluate the effect of flow rate on the friction slope. In the rotating flume experiment, a stationary recirculating debris flow is produced by controlling the rotating rate v.The friction slope J of the debris flow is experimentally evaluated by measuring the tangential slope of the flume. In the experiments, the properties of debris flow are observed, including the shape of the head, the jump of large particles, the low friction slope, the segregation of solid phase from liquid phase and the flow rate effect. The experimental results show that the magnitude of J increases with the increasing flow rate v under a certain conditions on v(e.g.1.88m·s^-1≥v>0.47m·s^-1 in this research).The segregation of solid phase from liquid phase occurs when v is too small(e.g.v<0.47m·s^-1 in this research).The displacement rate of gravels is much lower than the flow rate of the liquid phase. The experimental results provide an alternative method of producing debris flow and an alternative measurement method of friction slope. They also provide an experimental support for the further researches on the flow rate effect of debris flow.