Study On The LRP Of Post-Earthquake Emergency Logistics Considering Distribution Priority And Highway State

Earthquake disaster has sudden and unpredictable nature, and its powerful destructive force can cause serious casualties and huge property losses to human society. Emergency logistics, as the key of post-earthquake emergency rescue work, needs to meet the emergency demands of the disaster areas and reduce disaster losses in the greatest extent under the conditions of limited time, space and relief. Location-routing problem(LRP) integrates the location-allocation problem and Vehicle-routing problem, and it is the core of emergency logistics. The study on LRP of postearthquake emergency logistics can determine the number s and locations of distribution centers, relief distribution programs and seek the optimal route arrangement at the same time in order to ensure the efficiency of emergency supplies distribution.Based on the analysis of the existing literatures, according to the characteristics of earthquake disaster and post-earthquake emergency rescue, the LRP of emergency logistics system optimization was studied in the initial stage after earthquake. The specific contents are as follows:(1) The study on priority of emergency relief distribution after earthquake. First, the properties affecting the relief demand for disaster areas were selected, and the method of the fuzzy clustering analysis was used for demand points classification. Then the multi-attribute entropy weight decision-making method was used to sort the different classification in order to obtain the relief allocation priority. Finally, the relief satisfaction degrees of demand points were determined in the distribution system.(2) The study on the state of highway transportation after earthquake. Based on the analysis of highway construction grade and seismic damage grade, the impact of highway construction grade and damage grade on transport speed was analyzed, and the calculation method of the highway transportation speed was proposed. The impact of seismic damage grade on connectivity reliability was analyzed and the route reliability calculation method was also given.(3) The study on the construction and solving algorithm of LRP model in post-earthquake emergency logistics. Considering the priority of relief allocation and highway traffic state into the constraints, a multi-objective LRP model was established with the targets of minimum transit time, maximum relief satisfaction degree and maximum connectivity reliability. Because the model was a multi-objective and NP-hard problem and the LRP was to be solved as a whole question, the algorithm of solving the model that included chromosome encoding, selection, crossover and mutation and so on was designed based on the fast non-dominated sorting genetic algorithm(NSGA-II) and according to the characteristics of the model. At the same time, the whole process was realized by MATLAB software.(4) Case study. The related data of the 2008 Wenchuan earthquake were used to design the case in order to verify practicability and validity of the proposed method, model and algorithm.The achievements of the research would provide the theoretical and method guidance and references on emergency relief distribution for emergency rescue departments of the state and relevant social organizations, which could help to improve the efficiency of rescue work.