Study On Location And Route Optimization Of Road-rail Intermodal Transport Of Hazardous Materials

In recent years,the demand for chemical products continues to increase,and the transport of hazardous materials has become an essential part in industrial production.At present,the transportation structure of hazardous materials is single,and the transportation accidents are frequent,which has caused great impact on people’s life,environment and social safety.As an economic,efficient and safe mode of transportation,intermodal transportation has been promoted vigorously in China.The intermodal transport of hazardous materials has also been developed,and its efficient operation is inseparable from scientific and reasonable planning.The research on the two key problems of facility layout and transportation path optimization will help to reduce transportation cost,reduce accident loss and maintain social security.Therefore,this paper studies the intermodal location-route problem of hazardous materials from the government’s perspective,and the route optimization problem from the perspective of the intermodal transport operator.First of all,sort out the optimization problems of hazardous materials intermodal transportation systematically from the hazardous materials transportation and multimodal transportation,and combining with the characteristics of road-rail transportation,select traditional risks Model as a measurement method on the basis of summarizing the existing risk measurement models.Secondly,the medium and long term location-route problem is studied from the perspective of government.In the road-rail intermodal transport network,considering multiple hazardous materials and cargo separation scenarios,and combining with the constraints of multiple commodity flows,capacity constraints of handling stations,budget constraints.A mixed-integer linear programming model was established with the goal of minimizing system cost(locating cost,transportation cost,transit cost)and system risk(transportation risk,transit risk).The model is coded through MATLAB,solved with CPLEX,and the model is verified and analyzed through examples in the Beijing-TianjinHebei region.Compare the location-route strategy under the scenarios of separable and inseparable cargo flow,and conduct a sensitivity analysis on the investment budget and the maximum transfer capacity of the transit station.The results show that compared with the scenario where the goods flow cannot be separated,considering that the goods flow can be separated can effectively reduce “costs-risks” and improve the utilization rate of the transit station.Especially when the capacity of the transit station is low and the decision maker pays more attention to the risk,considering the separable flow has a greater advantage,the target value is reduced by 51.1% and the utilization rate is increased by 15%.In addition,appropriately increasing the investment budget and the maximum transfer capacity of the transit station can reduce risks and costs.Finally,the short-term path optimization problem is studied from the perspective of multimodal transportation operator.The characteristics of transportation mode and timevarying characteristics at operation level are analyzed based on the existing network facilities,and the risk measurement model of cross-period transportation under timevarying condition is established.Comprehensive consideration of factors such as traffic restriction,train operation plans,alternative routes,delivery time limits,network capabilities,and multiple commodity flows,establish an optimal model of intermodal transportation routing under time-dependent conditions with the goal of minimizing the total cost and total risk,the hybrid nonlinear model is solved by an improved ant colony algorithm.Small-scale numerical cases are used to verify the feasibility of models and algorithms,and four scenarios are compared in the case of the Beijing-Tianjin-Hebei region.The results show that the consideration of traffic restriction and train plan has a negative impact on optimization,especially on the risk,which increases by 2.78%-4.2%and 9.13%-15.33% respectively.The consideration of alternative routes has a positive impact on optimization,the risk reduces by 9.05%-12.61%.The comprehensive consideration of the above factors is more in line with the routing optimization in actual transportation.In addition,choosing a segmenting carrier with higher loading and unloading efficiency is helpful to reduce risks and costs.This paper studies the optimization of intermodal transportation of hazardous materials.On the one hand,it analyzes and verifies the superiority of considering the splittable cargo flow in facility location-route planning,and provides government decision-makers with a basis for network planning and decision-making;On the other hand,the analysis verifies that careful consideration of factors at the operational level is more in line with the optimization of actual transportation routes,which can provide reasonable decision-making suggestions for intermodal operators and improve market competitiveness.The paper contains 54 figures,35 tables,and 117 references.