Research On Optimal Escape Path Of Dam Break

The dam burst poses a threat to the life safety of the downstream residents,so it is necessary to plan a reasonable safety zone for the downstream residents in advance,and then to plan an efficient escape route between the disaster area and the safety zone.This problem involves multiple constraint conditions and optimization objectives.According to the development status of the problem,the paper focuses on the multi-constraint path optimization model in flat region and the digital elevation path optimization model in mountainous region.Firstly,a 0-1 integer programming model was established for the multi-constraint escape path optimization problem in flat area.The objective function of the model was the minimum expected travel time.In order to ensure that only the optimal path was finally generated,the unique path selection constraint was introduced,and the road capacity constraint was introduced to avoid congestion.Then the Lagrange relaxation method is proposed to deal with the difficult constraints and the relaxation model is decomposed into two sub-problems.An algorithm framework is designed by combining the subgradient algorithm,the label correction algorithm and the k-minimum short circuit algorithm to find the approximate optimal solution of the difference between upper and lower bounds.Considering that slope is also an important factor restricting path planning,the improved classical A* algorithm can solve the multi-objective path optimization problem in three-dimensional environment.According to the characteristics of the disaster site,two optimization objectives,slope and distance,were set.Through the improved A* algorithm,the evaluation standard for the shortest path under three-dimensional conditions was improved from the original cumulative spatial distance to the equivalent horizontal distance first,and then the shortest distance was calculated.The reciprocal function is used to balance the evaluation criteria of distance and slope,and the optimal path of distance and slope is obtained.Finally,the two frameworks are applied to the residential area of Xiaochi Town,downstream of Hejiapo Reservoir,Xinluo District,Longyan City,Fujian Province.The results show that the proposed framework can find the solution satisfying the conditions and verify the effectiveness of the framework.