Study On The Multi-period Location Of Inland Port Based On The Adjustment Of Multimodal Transport Structure

Since the structural adjustment strategy of multimodal transport has been put forward,the national government has issued a series of multimodal transport development plans,which clearly points out that 41 land port logistics hubs should be established.In order to further accelerate the structural adjustment of domestic multimodal transport,the government strengthened the top-level design,played a leading role,issued a series of special subsidy policies,and encouraged multi-party participation in the structural adjustment of multimodal transport.As the hub node connecting different modes of transportation in multimodal transport,the development and construction level of inland port is the key factor restricting the development of multimodal transport.The new strategic background puts forward new requirements for the construction of inland port.However,due to the short development time and lack of experience in the construction process,many stakeholders carry out the construction of inland port from the perspective of their own development.Due to the disordered construction of inland ports,the business scope of some inland ports overlaps,which leads to the inefficient operation of inland ports and restricts the development of multimodal transport.Based on the structural adjustment of,multimodal transport,combined with the problems existing in the actual development,considering the subsidy policy of structural adjustment of multimodal transport,and the maximum and minimum capacity limit of inland port,this paper establishes the single period location-allocation model and the multi-period location-allocation model of inland port respectively from the static and dynamic perspectives.First of all,considering the subsidy policy issued by the local government in response to the call of the state for the adjustment of transportation structure,the subsidy coefficient of sea rail intermodal transport is added into the model,and the maximum and minimum capacity limit of inland port is considered at the same time.Taking the total cost of the system,including construction cost,operation cost and transportation cost as the objective function,the single period location-allocation model of inland port is established to select the location of inland port And the path allocation of cargo owner point.Secondly,based on the single period location allocation model,considering the impact of the change of transportation demand and cost in different operation periods on the operation status of inland port,the multi-period location-allocation model of inland port is constructed to make decisions on the new inland port,the closure of existing inland port and the distribution of freight transport routes.Combined with the case study of Northeast China,this paper uses genetic algorithm to solve the problem,and verifies the superiority of the location distribution model of inland port,The results show that:(1)the systematic planning and construction of inland port can effectively improve the railway traffic volume and improve the inland transportation network,which is an important way for the smooth implementation of multimodal transport structure adjustment.(2)The multi-period location-allocation model can dynamically adjust the open or closed operation status of inland port in different periods according to the change of transportation demand and cost.Compared with the single period location-allocation model,the multi-period dynamic location-allocation model is more flexible,and can effectively reduce the total cost of the system and improve the transportation proportion of goods passing through the inland port.(3)When the freight demand,closing cost and road unit transportation cost increase,the total system cost will increase,and the proportion of goods transferred through inland port will also increase.When the construction cost,operation cost and railway unit transportation cost increase,the total system cost increases,and the proportion of goods transferred through inland port decreases.Among them,freight demand,inland port construction cost,highway unit transportation cost and railway unit transportation cost have great influence on the total cost of the system;the change of highway unit transportation cost has the greatest influence on the proportion of inland port goods transit.