Research On Optimal Design Of Highway-Rail Transportation Network For Self-provided Hazmat Tanks

With the diversified demand and business expansion,self-provided tanks have become the most common tool for liquid and gaseous hazmat.Furthermore,the equipment manufacturing and performance check of self-provided tanks have been widely normalized in China.The relevant applications in highway,rail and intermodal transportation are gradually standardized.Therefore,the optimization research on the highway-rail network of self-provided hazmat tanks has significant roles.Considering the research vacancy and method deficiency of existing works,this study takes the optimal design of highway-rail transportation network for self-provided hazmat tanks as the objective.In addition,the advanced operation strategies for modern hazmat transportation are formulated,and they are taken as the scientific theoretical reference and implementation guarantee.The main tasks are as follows:First,the calculation of risk indicators for the hazmat transported by self-provided tanks is developed.For the hazmat tank with standardized hardware,the transportation risk indicators are improved on the basis of existing researches.Distinguishing link/section risks and node risks,this study determines the relationship among risk quantification and cargo volume,accident probability,transportation mileage,and exposed population.We consider the short-acting hazmat and toxic one as the two main types.The key parameters of the former can be predicted by the artificial neural network.Furthermore,the latter can be calculated by the improved Gaussian plume model.Moreover,risk indicators provide the measurement basis for objectives in the network design modeling.Second,the optimal design of highway transportation network for self-provided hazmat tanks is proposed.This study aims at the basic network made up of expressways,provincial highways,inter-city expressways and urban branch roads.The objective includes reducing risks,expanding emergency capabilities and mitigating costs in actual operations.We analyze the decision-making of the government on available links,emergency center location and response allocation.Moreover,it involves the location of transfer depots,distribution plans,and tank routes under the regulation guidance.From the different perspectives of the government and transporters,a two-stage programming model is established.Meanwhile,the optimization relation is proved.According to the model characteristic,a numerical algorithm and a heuristic are respectively developed to solve problems of different scales.The case study is carried out based on the actual highway network of North Sichuan to Beijing.Under the background of LPG/NH3 transport tasks,the optimization results are calculated and analyzed.Third,the optimal design of rail transportation network for self-provided hazmat tanks is completed.This study deals with the basic rail network consisting of freight railways and enterprise-specific lines.It is necessary to analyze the rail-changing haulage of self-provided tanks.With the objective of reducing risks and mitigating operation costs,we clarify the qualitative factors such as response capabilities,geography,and environment for the location of handling stations.There is also the relationship between the layout of enterprise-specific lines and handling stations,and the long-distance railway routes between stations.The unified perspective of the government and transporters is used.Moreover,a hybrid optimization model with the fuzzy VIKOR method is established.According to the model characteristic,a numerical algorithm and a heuristic are respectively developed to solve problems of different scales.By the actual rail network of North Sichuan to Beijing and the background of LPG/NH3 transportation tasks,the case study is carried out.Furthermore,the optimization results are calculated and analyzed.Fourth,the optimal design of highway-rail intermodal network for self-provided hazmat tanks is achieved.The network consists of expressways,provincial highways,inter-city roads and freight railways.We analyze the ordinary transportation by highway and rail,as well as the transfer process between the two modes.With the objective of mitigating risks and costs,there should be the regulation decision on available links/sections,the location of transfer stations,and the configuration of transfer capabilities.Under the regulation of the government,the transporters determine intermodal routes of tanks,including the planned links/sections and transfer stations.A bi-level programming model is established from the relative perspectives.According to the model characteristic,a numerical algorithm and a heuristic are respectively developed.After that,a simplified management strategy using inverse optimization is proposed.Relying on the actual network of North Sichuan to Beijing and the background of LPG/NH3 transportation,the case study is carried out.Moreover,the optimization results are calculated and analyzed.On the basis of case study,we compare the qualitative and quantitative advantages of the three networks.On the whole,the three networks of self-provided hazmat tanks have different emphasis on practice principles and optimization effects.The analytical forms and complexity of their corresponding problems are different.In actual application,it is necessary to make comprehensive decisions based on regional specific conditions.With the construction of the national integrated transportation network,and the maturity of multimodal technologies,the highway-rail intermodal network will be an important direction in future.This research can support the unified decision-making system for the modern management of self-provided hazmat tank transportation.