Risk Assessment Of Pipeline And Application In Urban Water Supply Network

Water supply network is an important part of urban infrastructure,and its safe and efficient operation is the guarantee of the normal operation of the city.China’s water supply network assets are huge,but its own nature,environmental factors,operating conditions are different.Some pipelines have long service life and aging phenomenon,which leads to low management level,frequent pipeline damage events and high leakage rate.Pipeline risk assessment enables water supply enterprises to know the health status and importance of the pipeline in network,identify the pipeline with high risk,improve the management and maintenance level of the pipe network for water supply enterprises,and ensure the safe operation of the pipe network.Based on the research status in China and overseas in this paper,The combination of probabilistic risk assessment model and impact analysis method is selected and the pipeline risk evaluation system is also developed.The detection method of pipeline leakage is discussed in the risk identification of pipeline,and the influencing factors of pipeline health state are analyzed in combination with previous studies.According to the existing practical data,factors such as the diameter,material,service life,buried depth and working pressure of the pipe are selected as the evaluation indexes of the health status of the pipe.In the evaluation of pipeline health status based on logistic regression model,the data of evaluation indexes are standardized and preprocessed with dummy variables,and the weight of evaluation indexes is taken as the model parameters,and the damaged records are taken as the evaluation results to train the model,the results of pipeline health state evaluation are expressed by the failure probability.According to the analysis of the influence mechanism of the parameters on the indexes,the conclusions are basically consistent with the previous studies.The pipeline mechanism is used to optimize the model,and the confusion matrix and ROC curve are used to evaluate the effect of the model.After optimization,the F1 value and AUC of the model reach 0.75 and 0.82 respectively,and the effect of the model is satisfactory.In the pipeline risk assessment,the pipeline section is segmented by valve arrangement,the inoperable section is identified.The results of optimization of traditional hydraulic model show the inoperable at the pressure increase and water demand decrease in the downstream section of the inoperable segment after adding the pressure control water demand,which is more suitable for consequence analysis.The importance of pipeline is evaluated by the topological structure integrity of pipeline network base on the volume of inoperable fluid and the hydraulic reliability base on the shortage of water demand.The risk evaluation model is constructed by multiplying the assessment results of pipeline health status and importance.Finally,through the analysis of the pipeline network in a certain urban area of T city,the water supply pipeline risk evaluation system is applied to provide suggestions for the pipeline maintenance management of the water supply enterprise.The results show that 70.51% of the pipeline maintenance orders in the region in 2018 are above 0.5,and the pipeline health status evaluation effect was better.The damage rate is high,but due to the great connectivity and low flow rate of the pipeline network in this area,81.63% of the pipeline network importance index is lower than 0.1,the overall risk is low,and the safety of water supply can be basically guaranteed at this stage.