Cold Resistance Reliability Analysis Of Municipal Water Supply Network

During the cold wave,the phenomenon of pipe burst is serious in some cities,which has a great influence on the operation of city and the production and life of people.At present,the research on the stress of pipelines and the cold resistance reliability during the cold wave is almost a blank.Based on Specification for structural design of buried steel pipeline of water supply and sewerage engineering,the article established the mechanical model of buried water supply pipeline during the cold wave,and calculated the reliability of the pipeline and the reliability of the pipe network.The content mainly includes:The article made stress analysis of municipal buried water pipes during cold wave,and comprehensively considered the factors affecting the stress of the pipes,and established a mechanical model of urban water supply pipeline.The article improves the formula for calculating the frozen stress,and two points were taken into account when formulating the improvements,with one being the influence of air temperature and the other being the relationship between the buried depth of the pipe and the freezing depth of the soil.The article calculated the stress acting on the pipeline during cold wave by taking a water pipe in Changzhou as an example,and carried out safety evaluation of pipeline.Based on advanced first order second moment,the function of structure was established and the method of calculating the reliability of cold resistence was put forward,then cold resistance reliability of water supply pipeline was calculated.Pipe diameter,wall thickness,pipe yield strength,working pressure,buried depth of pipe and temperature difference were selected for sensitivity analysis in order to evaluate the importance of each parameter.The relationship between the cold resistance reliability of the water supply pipeline and the internal pressure,pipe diameter and wall thickness were studied.The article compared and analyzed the reliability of normal stress and the reliability after considering supplementary stress during cold wave.The result of advanced first order second moment and the result of Monte Carlo method are compared.The article realized the cold resistance reliability analysis of the municipal water supply network with practical significance.Based on the recursive decomposition algorithm,taking a pipe network as an example,the article calculated the cold resistance reliability during the cold wave of the pipe network,and classified the nodes in pipe network according to the reliability.The study provides a basis for the cold warning of municipal pipe network and has practical engineering value.