【摘要】 河床演变过程极为复杂，影响因素较多，但尽管它们的表现形式不同，归根结底，是由于水流的输沙不平衡所引起的。当宋沙量小于输沙能力时，河床发生冲刷；当来沙量大于输沙能力时，河床发生淤积。河床演变的结果是力图恢复水流输沙平衡，也就是说河床变形总是朝着使变形终止的方向发展。更多还原

【Abstract】 The bed evolution is complex with a lot of influential factors, but regardless of the differences of their manifestations, they are caused by the unbalance of sand transPOrtation by the stream. When the quantity of incoming sand is larger than the capacity of sand transportation, the channel degradation occurs; otherwise, the channel sedimentation.The result of bed evolution is to reach balance between scouring and silting, and the bed deformation is developed along the direction of deformation termination.更多还原