针对深厚淤泥软土滩涂的海堤龙口抗水流冲刷能力较差的问题,对海堤龙口水力学特性进行了研究分析,依据水力学理论及水量平衡原理建立了海堤龙口水力计算基本方程,该方程为非线性常微分方程,一般情况下难以给出精确解析解,依据数值分析理论利用经典四阶Runge-Kutta法结合MATLAB数值计算软件编程可给出数值解;另外,利用正弦函数拟合外海潮位周期变化特性,利用二次函数拟合围区库容-水位关系曲线,结合相关数值等效分析法及海堤龙口计算经验,给出了海堤龙口最大水位差与龙口宽度之间的近似解析计算方法;最后通过工程案例,利用MATLAB数值分析软件计算对比分析,认为本算法能满足工程实际应用要求。

In view of the inferior anti-scouring performance of closure gap of sea dyke in silt soft soil beach, we established the basic hydraulic calculation equation for the closure gap of sea dyke based on hydraulics theory and water balance principle. It is a nonlinear ordinary differential equation with precise analytical solution hardly obtained under normal condition. We can firstly obtain the numerical solution using the classic four-order Runge-Kutta method and MATLAB numerical software. In subsequence, we employed the sine function to fit the variation of the ocean tide position, and the quadratic function to fit the relation between storage capacity of closure area and water level. In association with numerical equivalent analysis and calculation experiences, we present the approximate analytic algorithm between the maximum water level difference and the width of closure gap. Engineering case study demonstrated that the numerical algorithm presented in this article meets practical application requirements.