ABSTRACT
Under the river affection, the shore dike is scoured by the river, so the river becomes wider and wider with the riverbank collapse, which are many collapse types mentioned in literatures. Inclined free face riverbank collapse by the river scouring is a new type of collapse, and is little involved in previous researches. The anti-force of collapse is from the anti-tensile strength of the riverbank, which increases with the water content decreasing, namely it increases with water level falling. When the tensile stress is more than the maximum tensile strength of the soils of the riverbank, the crack appears, and at this time the portrait crack of the riverbank appears, at last even to collapse. The riverbank collapse is result from the combined affection by the incoming runoff and sediment, the river channel scour and siltation evolution, the riverbank soil and the geological structure. X-stress of the top surface of incline free surface riverbank is the tensile stress.
