Study On Risk Assessment Technology Of Utility Tunnel With Natural Gas Pipeline

In recent years,China’s urban natural gas pipeline network has developed rapidly.Repeated excavation of urban roads caused by laying or repairing pipelines is a common problem.In order to avoid the "road zipper" pipeline laying method and realize the intensive use of urban underground space,natural gas will be used.The integration of management and maintenance of pipelines into public corridors is a general trend.Due to the special flammable and explosive nature of natural gas,the incorporation of natural gas pipelines will inevitably increase the risk level of public corridors.In order to ensure the safe operation of public corridors,it is necessary to carry out risk assessment techniques for public corridors containing natural gas pipelines.This article takes the public pipeline containing natural gas pipelines as the research object,and on the basis of collating and analyzing relevant data,divides the public pipeline corridor containing natural gas pipelines into two major sub-systems of the pipeline corridor’s own structure and the pipeline inside the gallery.The system carried out risk identification work and elaborated on the mutual influence between the two subsystems.In order to quantify the impact of natural gas pipelines on the failure of public corridors,ANSYS Workbench 15.0 was used to establish a finite element model for the impact of gas fire failures on other pipelines in the gallery,simulating the entire process of the failure of natural gas pipelines to form jet fires to the deformation of adjacent pipelines.Analyze the temperature,heat flux,equivalent stress,equivalent strain and total deformation of other pipelines in the corridor under the combined effects of coupling pressure,coupling temperature,and pipe pressure,and analyze the changing trend of each physical quantity with the change of operating parameters.To determine the physical quantity that best characterizes the severity of the consequences.This paper lays the foundation for the revision of the evaluation model of the consequences of public gallery failures.Based on the theory of system security theory,the probability of failure of major subsystems was analyzed from the four aspects of "human-machine-loop-pipeline".On this basis,an evaluation system for the probability of failure of public pipelines containing natural gas pipelines was established;The internationally popular approach,starting from the three aspects of safety consequences,economic consequences,and environmental consequences,established an evaluation system for the consequences of public pipeline failures;based on the simulation results,a revised plan to include natural gas pipelines in the evaluation of the consequences of public pipeline failures was proposed;The comprehensive evaluation analyzes the possibility of failure and the consequences of failure,and introduces a risk matrix method to combine the possibility of failure with the possibility of failure consequences to determine the risk level of the public corridor containing natural gas pipelines.Finally,using the risk assessment method proposed in this paper,a risk assessment of a public pipeline containing natural gas pipelines in China was carried out.Through the comparison with the actual situation on the site,the rationality o’ the evaluation method proposed in this paper was verified.