An experimental study of interaction between bank collapse and river bed evolution
摘要
This paper analyses the contribution rate of sediment in bank collapse and river bed evolution and presents a study on the patterns of non-viscous bank collapse and the interaction between it and the riverbed erosion/deposition through a series of experiments carried out in a bend flume. The experimental results reveal that the destruction of bank in the process of flow washout is a repeated interaction of water scouring the foot of bank,bank collapse along with the deposition and transportation of landslide substances. The mode and velocity of collapse and bed deposition rate and sediment interblending are largely affected by flow velocity distribution,flow turbulence and secondary flow,water level and the riverbed boundary conditions. The faster the near-bank flow and the closer the mainstream to bank is,the more unstable the bank will become. The extent of bank collapse and bed sediment deposition,the bed accumulative deposition rate is proportional to near-bank velocity and water level,but contrary when it comes to stable bank slope. When water level is higher,landslide substances interblend more violently with riverbed,especially on the bends where the transverse sediment transport happens tempestuously. The result reveals the mechanism and patterns of bank collapse and river bed evolution,which could provide a theoretical basis for the planning and design of flood control projects.