| Rubber bed is the foundation of gravity wharf and vertical breakwater. With the large scale development of ships, the ship stern flow has increasing scouring effect on rubble bed. Today, There are many rubbles bed of gravity wharf that have been scoured destructive. Many stones of the rubble bed have been scoured away, and the breakage makes the quay structures getting to be at risk.This paper presents a 2-dimensional simplified model under an ideal aligning condition of the rubble bed, and firstly numerically simulates the scouring problem of rubble bed by means of finite element software. ADINA software is used to process the FSI problem. A 2-dimensional model of a monolayer of stone on the horizontal ground is founded firstly, computing the incipient velocity of a monolayer of stone on the horizontal ground. Then compared the result with the foregone production, validate the simplified model presented in this paper to be feasible.The study discovered that the conditions of cloak between closer stones make the incipient velocity quite different, and present a new empirical formula of incipient velocity.To study the distribution characteristics of ship stern flow near the quay structures, Flow-3D software is used to simulate the screw propeller. By changing different locations in the water, get different distribution characteristics of ship stern flow accordingly. On this condition, confirm several kind of conditions that the stone would be scoured easily.According to the distribution characteristics of ship stern flow, a 2-dimensional numerical model is established to calculate and analysis the incipient velocity of rubble with the effect of the ship stern flow. The scouring mechanism of rubble bed under the influence of the ship stern flow is concluded, and the empirical formula of incipient velocity of the rubble bed is obtained by fitting method, and explaining the phenomenon that stones of the rubble bed have been scoured away.
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