城市燃气管道泄漏多因素耦合致灾机制研究

城市燃气管道很容易因复杂的城市环境影响而发生失效泄漏,而多灾害因素共同作用下的城市燃气泄漏的灾害后果更加严重,灾害形势更为复杂。为揭示城市燃气管道泄漏后多因素耦合作用下的动态致灾过程及灾害特征,首先采用系统框图对城市燃气管道泄漏灾害系统的内部结构进行分析,并在此基础上构建多因素耦合致灾数学模型;然后基于系统动力学理论,分别以燃气火灾、爆炸及毒害气体灾害为子模块,建立灾害系统动力学模型,并以模型检验来验证其适用性;最后应用于实际案例分析,采用系统动力学专用仿真软件,分别讨论了不同耦合条件下的单灾害和多灾害的动态致灾过程。结果表明:灾害子系统内部耦合度及同质耦合度增加,会促进各种灾害的增长速度、加速灾害发展,但不改变灾害损失的程度;而子系统间的耦合度增加,不仅会加快灾害的发展速度,还会提高其损失的程度、增加灾害损失的严重度。这表明,为有效控制复杂环境下的城市燃气管道泄漏灾害,应该削弱系统内部的因素耦合,孤立子系统间的因素耦合。

Research on the disaster-resulting mechanism of the multi-factors in addition to the urban gas pipeline leakage

To disclose the dynamic process and characteristic features of the disaster caused by the multi-factors plus the urban gas pipeline leakage,the present paper has first of all made an analysis of the interior structure and system boundary of the urban gas pipeline through the system-analytic framework. On such a basis, we have managed to build up a mathematical model of the multifactor involved coupling disaster mode,which can provide us with a guide to formulate a built-in equation of the system dynamics. Then it would be necessary to define the main variables in the system based on the system dynamics theory,while it is also possible to establish a disaster system dynamical model of the urban gas pipeline leakage as case samples of the gas fire,explosions, toxic and harmful gas leakage as a sub-class module so as to prove the applicability of the model through model test. And,finally,it would be possible to examine and check the case of gas leakage by means of the system dynamics simulation software named Vensim and the dynamic disaster-causing process of singular (taking fire disaster as an example) and /or multiple disaster factors under the different coupled conditions,respectively. The results of our analytic research demonstrate that the increase of the coupled degrees of the interior subsystem and homogeneity may lead to the disaster-aggravating rate,and,in turn,to accelerating the disaster aggravation,though they may not relieve the disaster loss extent. In addition,for the comprehensive disaster systems,the increase in the coupling between the various sub-modules of the disaster can not only accelerate the pace of the disaster growth and extend the loss degree,but more serious consequences should also be brought about by the sad disasters. Thus,it can be concluded that proper measures are to be taken to slash the coupling between the disaster subsystem and the homogeneity by isolating the factors coupled among the subsystems so as to effectively control and diminish the disasters of urban gas pipeline leakage in the complicated situations. Hence,as compared with the past research experience,the present paper has made an exploration of the relationship between the aggravation of the gas leakage and the elements of urban environment with the system dynamics method and examined the interactive impacts among the factors on the disasters. Thus,the work we have done is in a position not only to offer a new idea for disaster research,but also to open up a new direction for disaster control and prevention.