Explosion Risk Assessment Method And Application On Underground Space Adjacent To Gas Pipeline

Gas facilities and pipelines are important parts of the urban underground pipelines.Gas pipelines are one of the important infrastructures of municipal public utilities and one of the important infrastructures of urban.Gas pipelines,which are called the lifeline of city,are closely related to the development of economy and society and people's daily lives.Gas plays an extremely important role in optimizing the energy structure,improving the environmental quality,promoting the urban development and improving people's living standard.Gas is flammable,explosive and toxic.Once the gas pipeline leak,it can cause fire,explosion and poisoning incident easily,causing losses of life and property to the country and the people.The city gas pipelines are cross or neighbor to other underground space such as the storm water pipelines,the sewage pipelines,the subway,the civil air defense project,the underground store and so on.A summary of past accident cases shows that these underground spaces are high-risk areas where gas exploded and caused serious consequences.Based on the mechanism of explosion accidents in adjacent underground space of gas pipeline and the view of public safety,this paper establishes the risk assessment method of the gas explosion in the adjacent underground space by starting from the possibility of gas leakage,gas diffusion,gas accumulation,ignition and the severity of the explosion.And apply the method to solve practical engineering problems in Hefei,Anhui province.This research provides a new method and idea for the risk assessment of gas explosion,which has theoretical significance and application value to reduce the accident loss and improve the safety management level of urban gas pipeline.This paper includes the following parts:1)Study on the current development of related fields.The achievements on the risk assessment of urban gas pipeline and the theory of accident consequence analysis are summarized at domestic and overseas.2)Based on the analysis of the explosion mechanism of adjacent underground space,the hazard identification and determined the influencing factors and evaluation index of the risk assessment are finished,include the possibility of gas leakage,gas diffusion,gas accumulation,ignition and the impact of the explosion on people,buildings,adjacent pipelines and society.3)The possibility of gas leakage,gas diffusion,gas accumulation,ignition and the consequences of the explosion are quantitatively analyzed by using the Probabilistic Risk Assessment and Analytic Hierarchy Process.And the risk assessment method of the gas explosion in the adjacent underground space is established.There are 5 first-grade evaluation indexes:the possibility of gas leakage₁,the possibility of gas diffusion₂,the possibility of gas accumulation₃,the possibility of ignition₄ and the consequences of the explosion.The possibility of gas leakage includes 4 second-grade evaluation indexes:the outside interference₁₁,the corrosion₁₂,the pipeline defects₁₃ and the defects in ancillary facilities₁₄.The weights are:0.61,0.27,0.06,0.06,and₁ is adjusted by the leakage records₁^?.The consequences of the explosionincludes 3 second-grade evaluation indexes:the influence of explosive consequences on people₁,the influence of explosive consequences on buildings₂ and the influence of explosive consequences on other pipelines₃.The weights are:0.65,0.28,0.07,andis adjusted by the influence of explosive consequences on society₄.Finally,the risk assessment method of the gas explosion in the adjacent underground space is established as=₁×?₂+₃?×₄×.4)Applying the explosion risk assessment method to solve the problem of monitoring point selection and monitoring process in Hefei gas pipeline safety monitoring project.