对长江重要堤防典型二元结构堤基的地下水流运动进行了数值模拟。二维模拟结果表明：被河泓切割的承压含水层动态与江水位关系密切；表层弱透水层主要通过与承压含水层之间的补给排泄而受江水位的间接影响；全封闭防渗墙会制约堤防保护区承压含水层对江水位变化的响应；承压含水层透水性越强，这种制约作用越显著；全封闭防渗墙会使堤防保护区潜水含水层动态基本上不受江水位变化的影响。三维模拟结果表明：全封闭防渗墙端部自由绕渗会使端点附近承压含水层动态受防渗墙的影响减小；承压含水层的透水性越强，绕渗影响的程度和范围越大；绕渗在潜水含水层的作用则小得多，甚至可不予考虑。

The ground water movement in response to hydrological and metrological processes is simulated with saturated-unsaturated flow model for typical dyke foundation of double layers in lower and mid
dle Yangtze River. 2D model simulation results show the ground water regime of the unconfined & confined aquifer, and the regime differences under conditions with and without cut-off wall. The confined aquifer cut by the river thalweg keeps closely hydraulic relationship with the river. The cut-off wall of closure type would restrict and lower the influence of the river water level fluctuation on the ground water regime of the aquifer in the area protected by the dyke. The higher the ermeability of the confined aquifer, the more greatly the cut-off wall would change the ground water regime.The cut-off wall of closure type would make the unconfined aquifer respond less to the river water level change. 3D model simulation results demonstrate the influence of water flow moving around the lateral ends of the cut-off wall. It would lower the influence of the cut off wall on the ground water regime of confined aquifer near the ends. The more permeable the confined aquifer, the more great the by-pass flow would appear. The influence of the by-pass flow on the unconfined aquifer is little and even could be neglected.