海涂垦区骨干除涝排水系统的优化设计

Optimal Design of Main Drajnagc Projects in Reclaimed Seabeach Areas

提出联合运用非恒定流技术和优化技术确定海涂垦区骨干除涝系统规模的方法,有利于提高计算精度,降低工程造价。优化模型以投资最小为目标,约束条件包括水量平衡、圣维南方程、过闸流量方程、闸河匹配要求、工程规模限制等。把每一项除涝工程作为一级来考虑,将除涝工程的优化问题转化为多阶段决策问题,用动态规划求解优化模型。在进行非恒定流演算时,设计了特征线法、扩散法、两步法三种差分格式,可以自动淘汰不收敛的差分格式。实例表明,提出的方法是有效而实用的.

A method combining a mathematical programming model with an unsteady flow model is presented to determine the optimal sizes of main drainage projects in the reclaimed seabeach area, improving computional accuracy and reducing project costs. An objective is to minimize the cost, and constraits come from water blance, Saint-Venant equation, outflow formula of a sluice gate, the requirement of matching a sluice with a channel, and limitations to the size of a project. The optimization models are solved by dynamic programming method, in which each project is regarded as one stage, and the optimization problem is translated into a multi-stage decision process. In solving the unstead flow models, three finite difference methods, i. e., a method of characteristics, a diffusive scheme, and a two-step method are given, which automaticaly avoid nonconvergence. The results of case studies show that the above mentioned method is practicable and efficient.