Optimization Of Container Management Strategy For Sea-side And Yard-side In Large Transshipment Terminals

In order to meet the demand for container transportation,the trend of large-scale container ships is becoming increasingly evident,which also leads to the transportation volume of transshipped containers accounting for the majority of the total container transportation volume.As the main venue for container loading and unloading operations and temporary storage,transshipment terminals are one of the winning points in improving container transportation efficiency.Compared to import and export terminals,the arrival and departure of containers in transshipment terminals are more concentrated,and the loading and unloading tasks are more arduous.Therefore,how to maximize the utilization of space resources in transshipment terminals and the operational efficiency of loading and unloading equipment will be the core content of this study.For improving the enforceability and efficiency of transshipments operation plans in terminals,this thesis introduces a new "double-line ship mooring" operation mode,fully considering the uncertainty of container loading and unloading demand,congestion of yard roads,and delayed container transportation.This thesis is based on the problem of space allocation in transshipment terminals,and studies the series of tactical and operational operation plans involved in the loading,unloading,and storage activities of transshipments from the terminal’s sea-side to yard-side.The specific research content is as follows.(1)In response to the integrated optimization problem of berth allocation,quay crane assignment,and yard space allocation at the tactical level,this thesis considers minimizing the time deviation cost of ships and the horizontal transportation cost of the transshipped containers under the "double-line ship mooring" operation mode of the feeders.This operation mode can achieve direct container transfer between two ships through parallel berthing,thereby improving transfer efficiency and alleviating storage pressure in the yard.Based on this problem,this thesis constructs a mixed nonlinear programming model and designs a method based on particle swarm optimization(PSO)algorithm to solve the problem.The experimental part not only proves the effectiveness of the model and algorithm,but also proves that the "double-line ship mooring " operation mode has significant advantages in reducing port operation costs,improving the efficiency of quay crane operations,and saving storage space resources.(2)In response to the integrated optimization problem of space allocation in the tactical layer and container allocation in the operational layer at the yard,this thesis incorporates the berth plan obtained from problem one into this study.Under the same visiting period of transfer ships,the impact of uncertain container demands and road congestion on this problem is considered.This thesis focuses on analyzing the impact of the number of sub-blocks,which have an impact on the degree of traffic congestion on each link,operating simultaneously on the passage time of trucks.Based on the analysis of this problem,this study constructs a two-stage stochastic optimization model and designs an improved Benders decomposition(BD)algorithm for problem solving.Numerical experiments part not only proves the effectiveness of the model and algorithm,but also proves that considering yard congestion can improve decision-making and effectively alleviate road congestion during operations,thereby reducing costs in truck loading and unloading transportation.(3)In response to the integrated optimization problem of container allocation and yard crane deployment in the operation layer of the yard,different from the research in problem two,this thesis considers yard operation plans under different visiting periods of transfer ships to achieve comprehensive consideration of actual port operations.Given the berth plan and yard template plan,this study focuses on analyzing the impact of different ship visiting periods on the problem of delayed transshipment of some containers after unloading to the yard.Based on the analysis of this problem,this thesis constructs a mixed Integer programming model,and designs an improved BD algorithm to solve the problem,mainly by improving the initial upper and lower bounds and adding effective inequalities.Numerical experiments part not only proves the effectiveness of the model and algorithm,but also proves the necessity of considering delayed container transportation,which can effectively avoid the cost of container turnover caused by mixed stacking of containers in different periods of transportation.This thesis studies the management of transshipped containers in the transshipment terminals from the tactical level to the operational level,and from the sea-side to the yard-side.The tactical decisions include: berth allocation,quay crane assignment,and yard storage space allocation;the operational decisions include: container allocation and yard crane deployment.In order to make the research more practical,the study considers the impact of factors such as the " double-line ship mooring " operation mode of feeders,uncertain container demand,yard road congestion,and delayed container transshipment on decision-making while optimizing the problem.Numerical experiment parts also prove that this study can provide effective decision-making solutions and some management insights for the management of transshipped containers at container terminals.