为研究堤基接触冲刷渗透破坏机理，对粘土层与砂砾石层之间各种成因的粗糙面或缝隙渗透性用光滑裂隙的渗透性代替，地层整体的渗透性由裂隙、砾石层和砂砾石层的渗透性决定，以细砂的起动速度为判别标准，通过分时段的稳定流计算，接触面附近的细砂从出渗口开始流出，出渗口附近的渗透系数首先增大，然后逐步向内部发展，以垂直河岸方向的发展最为迅速，甚至形成贯通性集中渗漏通道。

A new model has been developed for studying the mechanism of infiltration destruction by contact scouring between the hardpan and grid. The permeability of coarseness gap that formed by different lithology is substituted by the permeability of slippery cranny, and the permeability of the stratum can be expressed by a combination of the permeability of gap and sand and gravel. The starting speed of the fine sand can be used as differentiation criterion. To calculate the fine sand moving by stabilization flow theorem in different time part, the fine sand near the orifice flows out of the stratum at the beginning. At first the permeability coefficient near the orifice becomes larger, and then it developes inside. It will develope rapidly in the direction perpendicular to tho bank, and even forms a concentrate leakage passage.