Abstract:

Under the dynamic change of road conditions and multi-party disaster coupling system， how to choose the disaster relief path according to the specific situation of road damage has become an urgent problem to be solved at present. Earthquake disasters and other emergencies show the characteristics of a complex physical-social coupling system. In addition， some sections of the road system appear functional failure under the action of strong earthquakes， which hinders the transport of relief supplies and evacuation of casualties. In the disaster coupling system， the government and social organizations need to participate in the rescue. First of all， in the early stage after the earthquake， it was difficult for the external rescue forces of the government to quickly enter the scene because of traffic interruption and poor information， while social forces could guide the people to carry out self-rescue and mutual rescue， but the continuous social forces occupied the rescue road， resulting in traffic congestion， “saving people will be saved by others” and other secondary disasters. Secondly， socialized disaster prevention and mitigation is an important direction of current and future disaster prevention and mitigation mechanism reform， the government and social organizations cooperate， not only effectively make up for the “government failure” defect， but also promote the stable development of society； Finally， to guarantee the amount of disaster relief required by the disaster area， the government has increased financial support for social organizations to relieve the pressure of disaster relief.According to the different input strategies of government and social organizations in disaster relief， three cooperation modes are summarized， namely non-cooperative rescue mode， cooperative rescue mode， and government subsidy mode. Then the differential game model of cooperative transportation between government and social organization is constructed. First， three differential game models of cooperative transportation between government and social organization are described. Secondly， the optimal level of the relief effort， subsidy ratio， amount of relief， and system equilibrium income of both sides of the game are obtained and analyzed. Thirdly， the balance strategies of the three modes are compared and analyzed. Finally， the sensitivity of key parameters to the equilibrium results is analyzed. It is found that three disaster relief modes have different coupling effects in the social system. Among them， the non-cooperative rescue mode is prone to fall into the “prisoner's dilemma” of not subsidizing weak participation. When the government and social organizations transition from non-cooperative relief mode to government subsidy mode， the Pareto improvement of relief efficiency can be realized. When the two parties choose to cooperate， the amount of disaster relief and the system equilibrium benefit is strictly superior to the non-cooperation and government subsidy modes. Three traffic situations in the physical system have the same coupling effect. Both the quantity and benefit of disaster relief under unblocked conditions are better than those under congestion and congestion conditions. In addition， the amount of disaster relief is affected by the joint efforts of the government and social organizations， and the amount of disaster relief increases with the increase of the input of one party. If social organizations predict that the government will increase relief spending， they will choose to maintain the original level of relief efforts to avoid unnecessary costs. In terms of case selection， the Lushan Earthquake in Sichuan Province in 2013 is selected as the case analysis object. Key parameter values are obtained from relevant authoritative organizations， such as Xinhua News Agency， China Youth Daily， and the website of the Ministry of Finance.Three modes of cooperative transportation between government and social organizations are summarized and the coupling results of physical and social systems after the earthquake are analyzed. Relevant research has certain theoretical reference significance for further improving the cooperative transportation of disaster relief materials after the earthquake.

Key words: post-earthquake relief, differential game, physical-social coupling systems, road capacity, co-transport