Research On Route Optimization Of Hazardous Materials In Railway Transportation With Multi-demands Under Uncertainty

With the rapid development of China's chemical industries,the demand for hazardous materials increases day by day.As a safer mode of transportation,the demand for the transportation of hazardous materials by railway also increases greatly,and the complexity of transportation network and the uncertainty of market demand are more and more obvious.At the same time,because hazardous materials have dangerous characteristics such as being flammable and explosive,it brings opportunities as well as great challenges to railway transportation.To better meet the market demand,this paper combines the actual situation and characteristics of hazardous materials with railway transportation,the probability of accidents is associated with the train speed,and the risk analysis of hazardous materials with railway transportation is carried out.Based on the research of the problem under certain conditions,the multi-demand hazardous materials railway transportation route optimization model with time window under the uncertain conditions of unit transportation cost and transportation capacity is proposed.Finally,the genetic algorithm based on the lower bound of waiting time is designed,and the effectiveness of the model and algorithm is verified by case studies.The main research contents of this paper are as follows:(1)Based on the analysis of the influencing factors of railway transportation risk,the train speed is regarded as the main determinant of accident probability,and the number of people exposed to the danger is regarded as a measure of the consequences of accidents,and then a risk assessment model suitable for railway transportation of hazardous materials is established.(2)From the perspective of carriers,this paper studies the route optimization of hazardous materials in railway transportation.It is stipulated that the running speed of different sections of the train can be different.Taking risks and time windows as constraints,a multi-demand hazardous materials railway transportation route optimization model with time windows under certain conditions is established.The objective is to minimize total generalized transportation costs(including transportation cost,penalty cost due to violation of time window,processing cost and waiting time cost).Finally,a genetic algorithm based on the lower bound of waiting time is designed to solve the problem.(3)Considering the uncertainty of parameters such as unit transportation cost caused by some human factors and market factors in a real-life railway transportation of hazardous materials,the multi-demand hazardous materials railway transportation route optimization model with time window under uncertain conditions(include unit transportation cost,processing cost and transportation capacity)is proposed,the genetic algorithm based on the lower bound of waiting time is used to solve the model.Finally,the practicability and effectiveness of the model and algorithm are verified by case studies.