Research On Emergency Path Planning Of Coal Mine Based On Improved Dijkstra Algorithm

The environment of the coal mine roadway is complicated and changeable.A reasonable and efficient evacuation path planning can help the people trapped in the underground to escape from the danger effectively after the mine disaster occurred.Therefore,studying the underground emergency path planning is of great significance to coal mine emergency rescue.In order to solve the problems of high space complexity and random storage of intermediate nodes in the classic Dijkstra algorithm,we have proposed an improved Dijkstra algorithm based on adjacency list and binary sorting tree.The algorithm uses an improved adjacency list and connection weighting matrix to replace the original connection matrix,reducing the space complexity of the classic Dijkstra algorithm.After that we introduced a binary sorting tree to sort the interamediate nodes which helped reducing the calculation times of the intermediate nodes.Aiming at the practical problems such as multiple exits,crowd crowding and secondary disasters in the emergency evacuation period after a mine disaster,we proposed a search strategy for marked exit nodes;hot nodes and optimal nodes.By marking the exit node,the improved algorithm performs the backtracking operation for one time with the marked exit directly outputs the optimal escape exit,reducing the running time of the algorithm.By marking the hot nodes and artificially increasing the equivalent length of the corresponding roadway,the crowd dispersed to escape so the possibility of crowding was reduced.By marking the escape nodes of the personnel,the real-time comparison with the mine safety monitoring data is performed,and the miners are reminded to switch the escape path in time after the occurrence of the secondary disaster.According to the simulation analysis of personnel emergency evacuation based on the roadway point network model in an underground coal mine,the time of single sub-path planning of the improved algorithm was reduced from 1.2 seconds of the classical Dijkstra 0.95 seconds,the time of the single search is reduced by 0.25 seconds.In the case of evacuation of multiple people,the average running time of the algorithm was reduced by 18 seconds,the average escape time was reduced by 15.5%,and the switching process of the overall planning results took about 1 minute.The results show that the project can meet the emergency evacuation needs of many people in the underground coal mine under the disaster environment,and can guarantee the safety evacuation from the underground coal mine with short overall escape time,which has certain practical value.