Research On Ship Lock Scheduling Problem Of Three Gorges Gezhouba Hydro-junction During Lock Maintenance

The Three Gorges-Gezhouba Water Control Project plays a pivotal role in the development of the Yangtze River Economic Belt,making a substantial contribution to the economic growth of the upper and middle reaches of the Yangtze River.However,as the operational duration of the Three Gorges-Gezhouba Water Control Project increases,the related lock facilities and equipment require periodic maintenance and closure.During the closure period,the project’s capacity to control water traffic significantly decreases,resulting in severe congestion and a backlog of vessels awaiting passage.Therefore,it is of great practical significance to optimize the ship lockage scheduling process during the maintenance period and improve the efficiency of ship navigation scheduling in the Three Gorges-Gezhouba Dam.The main contents of this paper are as follows :(1)A mathematical model for ship lock scheduling during the maintenance period at the Three Gorges-Gezhouba cascade navigation hub was constructed.Based on the analysis of the characteristics of ship lock scheduling during the maintenance period,a mathematical model for ship lock scheduling during the maintenance period was developed.The model divided the ship lock scheduling problem into dynamic scheduling and static scheduling according to the ship congestion situation,and set the optimization objectives as minimizing ship waiting time and maximizing ship navigation quantity,respectively.Several relevant constraints for ship lock operation and chamber arrangement were proposed.(2)Optimize the bald eagle search algorithm.In order to solve the problem of ship lockage scheduling during maintenance period,this paper analyzes and improves the shortcomings of basic bald eagle search algorithm,such as easy to fall into local extremum,rapid decline of population diversity and redundancy of search behavior.The mechanism of elite population guidance and population memory crossover is proposed to optimize the algorithm.The algorithm is adaptive by improving the core parameters.In addition,the redundant search mechanism is eliminated,and the improved algorithm is named ABES.(3)Model solving and example verification.The ship lock scheduling problem during lock maintenance period is divided into three sub-problems : lock allocation problem,lock chamber arrangement problem and timetable optimization problem.We design the corresponding algorithm to solve the problem.The ABES algorithm is used to solve the ship lockage scheduling problem during the maintenance period,and the experimental results are given.In the experiment,the average waiting time of the ship in a maintenance cycle and the passing volume of the ship are statistically compared to verify the effectiveness of the model and algorithm.The ABES algorithm is compared with the other seven intelligent optimization algorithms on the CEC2013 function test set.The experimental results and the Wilcoxon signed rank test results show that the improved algorithm has stronger comprehensive optimization performance and the robustness of the algorithm is significantly improved.The actual historical data of the navigation of the Three Gorges-Gezhouba dam is used for experimental verification.The optimization results of the bald eagle search algorithm before and after the improvement are compared to evaluate the performance of the ABES.In a scheduling cycle,the average waiting time of the ship can be reduced by about 3 hours,the average utilization rate of the lock chamber area can reach more than 75 %,and the ship throughput can be increased by 6ships.The results show that the model and algorithm proposed in this paper can be used for ship lock scheduling during lock maintenance period,which effectively reduces the waiting time of ships and improves the navigation efficiency of locks.