In channel optimization, the objective function and the oft‐used trapezoidal cross‐section channel in excavation models are not comprehensive. The parabolic composite section channel is a new type of channel with a parabolic slope and a horizontal bottom. To improve channel optimization, we propose models of a parabolic composite section channel constructed with excavation, filling, and half‐filling. We establish three parabolic composite cross‐section channel models that consider freeboard, and we establish three construction methods. The objective is to minimize the combined cost of excavation, filling, and concrete lining, and the objective function covers all construction methods and construction costs. To avoid missing the feasible optimal solution, the shuffled frog‐leaping algorithm (SFLA) is used to optimize the three channel models. An objective function within the acceptable range of parameter variation is represented by a MATLAB 3D rainbow graph, and sensitivity analyses of various section parameters are carried out. The results show that the model constructed with excavation has the lowest investment cost. The bottom width of the parabolic composite channel is 1.74 m, the channel top width is 5.69 m, the channel depth is 3.22 m, the channel excavation section area is 14.1 m², the channel section lining length is 9.62 m, and the minimum cost per kilometre is 591,000 yuan. SFLA is superior to the differential evolution, artificial bee colony, and particle swarm optimization algorithms in terms of convergence speed and optimization accuracy, and the objective function is the least sensitive to the opening width of the parabola.

中文翻译：

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抛物线复合截面明渠的模型优化和参数敏感性分析*

在渠道优化中，开挖模型中的目标函数和经常使用的梯形截面渠道并不全面。抛物线复合截面通道是一种新型的具有抛物线斜率和水平底部的通道。为了改善通道优化，我们提出了一个采用开挖，填充和半填充构造的抛物线型复合截面通道的模型。我们建立了三个考虑干舷的抛物线形复合截面通道模型，并建立了三种构造方法。目的是最大程度地减少开挖，填充和混凝土衬砌的总成本，目标功能涵盖所有施工方法和施工成本。为避免错过可行的最优解，改组的蛙跳算法（SFLA）用于优化三个通道模型。在参数变化的可接受范围内的目标函数由MATLAB 3D彩虹图表示，并对各种截面参数进行了灵敏度分析。结果表明，采用开挖构造的模型具有最低的投资成本。抛物线形复合通道的底部宽度为1.74 m，通道的顶部宽度为5.69 m，通道深度为3.22 m，通道开挖断面面积为14.1 m²，通道断面衬砌长度为9.62m，每公里最低成本为59.1万元。SFLA在收敛速度和优化精度方面优于差分进化，人工蜂群和粒子群优化算法，并且目标函数对抛物线的开口宽度最不敏感。