Research On Risk Assessment,Network Optimization And Safety Supervision Game Of Hazardous Materials Transportation

With the growth of China’s industrial economy,the volume of hazardous materials transportation is rising,and the density of hazardous materials transportation vehicles in the road network also shows an upward trend.On the one hand,the rapid growth of the volume of hazardous materials transportation marks the rapid development of industry,which escorts the social and economic development.On the other hand,it also increases the probability of accidents on the transportation road,causing damage to public and the environment near the road.Although our government has promulgated many laws and regulations on the safety of hazardous materials transportation,there are still occasional major hazardous materials transportation accidents.In addition,there are some deliberate attacks in the international community,which is a risk factor that can not be ignored.Once the deliberate attacker aims at the hazardous materials transportation link with weak defense ability and serious accident consequences,it will cause impacts and losses to the public.Therefore,accurately identifying the critical risk of the road network,scientifically making decisions on the optimization of the hazardous materials transportation network,especially considering how the government implements effective safety defense strategies and supervision mechanisms under the background of deliberate attack,are not only important problems that need to be solved urgently,but also hot issues in academic research.The main research work of this paper is as follows:(1)The spatial risk model of improved gravity model is studied.Based on the traditional gravity model,four key risk factors in the risk assessment of hazardous materials transportation are proposed,and the spatial risk assessment model is constructed by integrating the safety factors and the topological characteristics of road network.The proposed model is verified by using the road data of a local area in Beijing,and a comparative experiment aiming at the shortest distance,minimum population risk and minimum improvement risk is designed.The results show that the improvement risk and social risk of the spatial risk assessment model proposed in this paper are the least.(2)The optimization of hazardous materials transportation network under the government blocking strategy is studied.In order to ensure the safety of hazardous materials transportation,the government adopts the blocking strategy for the risk road,the enterprise plans the transportation path according to the government’s decision,and this section puts forward a bi-level programming model under the improved risk.The goal of the upper-level planning is that the government decides the blocking strategy under a certain road service level.In the lower-level planning,the enterprise goal is to determine the demand point and vehicle transportation path of vehicle service considering the constraint of the government’s blocking strategy and the transportation task and cost.Through the scenario study and discussion,it is found that when the government’s blocking strategy is a flexible,the government has a variety of blocking strategies under a specific road service level,and the optimal service route of enterprises remains unchanged.The research on network optimization under improved risk provides a theoretical basis for government and enterprise decision-making,and has certain reference significance to the transportation management based on blocking strategy.(3)The optimization problem of hazardous materials transportation network under dynamic improved risk is studied.Based on the tidal characteristics,the concept of dynamic zero-sum risk is proposed,and the bi-level programming model of hazardous materials transportation network based on dynamic zero-sum risk in discrete time is constructed.In the upper-level planning,the government determines the maximum blocking strategy set of roads in each time period according to the risk change and the minimum road service level in different time periods.In the lower-level planning,the enterprise optimizes the transportation route and route according to the government’s blocking strategy and dynamic risk changes in each time period.By comparing the bi-level programming results of the whole period,the global optimal decision period and content are obtained.The bi-level programming problem based on dynamic improved risk has certain reference significance for the decision-making of government blocking in different periods,and has certain reference value for enterprises to improve transportation efficiency and reduce transportation costs.(4)The security defense game of hazardous materials transportation network under the background of deliberate attack is studied.As an external factor with strong destructive power,deliberate attack poses a threat to the safety of transportation of hazardous materials.Considering this background,this paper proposes a game model for the security defense of hazardous materials transportation.Taking the key edge of the network topology as the key object,this paper constructs a comprehensive risk index system from the perspective of the external and internal characteristics of the road.Four typical risk scenarios are proposed,and the game equilibrium strategies of attackers and defenders under different risk scenarios are studied.This method has certain significance to improve the level of road safety defense and reasonably allocate defense resources.(5)The evolutionary game problem of hazardous materials transportation safety supervision under the background of deliberate attack is studied.Thinking that the transportation has the risk of deliberate attack,there is a game between the government,transportation enterprises and the attacker.This paper puts forward the tripartite evolutionary game model of government-enterprise-attacker,and analyzes the equilibrium strategy of the model.Then it introduces the supervision mechanism of government dynamic punishment and dynamic punishment-subsidy,and discusses the evolutionary stability strategy of players under the two mechanisms through system dynamics simulation.The tripartite evolutionary game model provides a scheme for the government to design strict supervision strategy,enterprises to improve safe transportation technology,and so as to curb the destructive behavior of attackers.