Research On Fuzzy Evaluation Of Safety Risk Of Natural Gas Pipeline In Mountain Area

Natural gas is a precious energy necessary for the development of modern human society.The most effective way to transport natural gas resources is pipeline transportation.Because natural gas is inflammable and easily diffused,once an accident occurs in the pipeline,it will have serious consequences to the surrounding environment and the safety of human life and property.Therefore,in order to prevent the disaster caused by pipeline accidents,it is of great significance to evaluate the safety risk of natural gas pipeline.The safety risk assessment of buried natural gas pipeline in mountainous area is particularly important.Due to the complex terrain in mountainous areas,landslides are often associated with the occurrence of pipeline damage in mountainous areas prone to landslides,which leads to accidents.At present,the safety monitoring of natural gas pipelines in mountainous areas in China mostly relies on sensor networking technology,that is,a variety of sensors are deployed to carry out real-time monitoring of pipeline safety-related risk factor indicators,and the monitoring results are sent to the monitoring center for staff monitoring.Although this approach can comprehensively monitor all kinds of risk factors affecting pipeline safety,it lacks the function of combining all the information of monitoring indicators and evaluating the comprehensive safety level of the pipeline.In this context,aiming at the field investigation of the geological disaster monitoring site of a natural gas pipeline in a mountain area,based on fuzzy mathematics and according to the actual needs,this paper defines the system structure and modeling method of the assessment process,establishes a fuzzy model of pipeline safety risk assessment based on fuzzy mathematics,and applies it to the practice of natural gas pipeline safety risk assessment for the first time.It has obtained effective safety warning effect.The main work is as follows:(1)Investigate the environmental condition of monitoring points and the buried condition of sensors,and use principal component analysis method to reduce the dimension of GNSS displacement monitoring data,so as to simplify and compress the displacement monitoring data;A variety of risk factors,including landslide factors,are analyzed and classified theoretically,and the rationality of classification levels of risk factors is verified by correlation analysis method.(2)Improved the fuzzy comprehensive evaluation model and designed the pipeline safety risk assessment model 1 based on the fuzzy comprehensive evaluation method,including the classification of evaluation indicators based on the classification results of risk factors.A variety of weighting methods were used to determine the weight sets of indicators at all levels.The second-level indicators were weighted by grey correlation analysis method,and the sample set of scoring values of the first-level indicators corresponding to the second-level indicators was constructed.As an alternative to the objective data required by the entropy weight method,the problem that the upper-level indicators could not be objectively weighted in the multi-level fuzzy comprehensive evaluation model due to the lack of actual sample data was solved.According to the actual situation and expert opinions,the comment set is divided and the membership function corresponding to the comment set is determined.(3)In order to reduce the deviation caused by a single assessment model for risk assessment,fuzzy reasoning method is introduced to design a comprehensive assessment model of pipeline safety risk 2.Based on the fuzzy mathematics theory,the structure of the fuzzy rule base is divided,the membership function of each fuzzy subset is determined,and the output of the fuzzy reasoning model is used to divide the pipeline safety risk level and the simulation experiment of the fuzzy reasoning model.(4)Test and compare the above two risk assessment models and their mixed models based on historical sample data.The test results show that the integrated application of the two models can improve the correctness and reliability of pipeline safety risk assessment.(5)Analysis of engineering application results and case verification of comprehensive risk assessment model.In the actual disaster monitoring and early warning system,the fuzzy evaluation model of natural gas pipeline safety risk is applied.The practice shows that the designed evaluation model can greatly improve the work efficiency reduce the probability of missing judgment and wrong judgment,and improve the accuracy and reliability of pipeline safety risk monitoring and early warning.