Path Optimization In Emergency Evacuation After Urban Natural Gas Pipeline Leakage Accident

In recent years,natural gas pipeline network develops rapidly.Fire and explosion accidents caused by pipeline leakage are increasing,and it always has a serious effect on residents and environment nearby.For the purpose of safety,it's necessary to organize people to evacuate when natural gas pipeline leaks.The intent of the paper is to solve the problem of route selection in evacuation,which can improve the efficiency of evacuation.Based on discussion of causes and consequences of natural gas pipeline leakage,main influence factors of route selection in evacuation are determined in the paper.And single-objective and multi-objective path optimization models are established separately to obtain the optimal path in emergency evacuation.The major contents are as follows:(1)According to event tree analysis,determine the consequences of natural gas pipeline leakage.And consequences are simulated by ALOHA to obtain affected areas under each accident scenario.(2)Analyze the major influence factors of route selection in emergency evacuation after natural gas pipeline leakage,and methods of quantifying each factor are given.(3)Establish three single-objective optimization models,separately based on path length,safety and reliability,and Floyd algorithm is used to obtain the optimal path.Then,a multi-objective optimization model is established and corresponding optimal path is gained by means of weighted sum method.(4)Taking a natural gas pipeline in Beijing as an example,analyze the affected area caused by pipeline leakage.Calculate and obtain the optimal paths based on single-objective and multi-objective optimization in emergency evacuation.