Vulnerability Assessment Of Urban Storm Sewer System And Determination Of Fragile Pipe Sections

In recent years,most of the cities in China have encountered urban waterlogging.The loss of economic property and the increase in the number of affected people caused by urban waterlogging which people are increasingly concerned about.In order to ensure the safety of people's lives and properties,the government has successively issued documents to improve urban drainage and flood control work,and strive to improve the city's drainage and flood prevention system by around 2025.The urban storm sewer system is one of the main components of the urban drainage flood prevention system,and its role is to drain the rain out of the city.In order to improve the urban storm sewer system's ability to withstand rainstorm,the urban storm sewer system vulnerability assessment research needs to be conducted.This paper analyzes the urban storm sewer system and its status in detail from three aspects: layout form,design standard and management method.On this basis,the concept of vulnerability was introduced into the urban storm sewer system.Combined with the characteristics of the urban storm sewer system,the concept of urban storm sewer system vulnerability was proposed,and the four types of factors affecting the urban storm sewer system vulnerability were summarized: Design factors,hydraulic factors,external damage factors,management factors.Afterwards,according to the mathematical characteristics of the urban storm sewer system,combined with the theory of maximum flow in the network,the vulnerability assessment model of urban storm sewer system was established.After obtaining the overall vulnerability of the urban storm sewer system,this paper hopes to identify fragile pipe section in the system.It is these fragile pipe section that cause the overall fragility.In the subsequent reconstruction,these fragile pipe section can be preferentially transformed.This paper uses the solution of the Maximum Flow-Minimum Cut Theorem to find the minimum cut set in the system first,then uses the idea of establishing the vulnerability evaluation model before,and uses the judgment formula to judge the minimum cut set to find the fragile pipe section.Taking the storm sewer system of a university in Xi'an as an example,the vulnerability of the storm sewer system in the university is 0.945.It is proved that the storm sewer system in this area is relatively fragile and it is not easy to waterlogging,and the fragile pipe section of this storm sewer system was found.The assessment of urban storm sewer system vulnerability and the determination of fragile pipe section can provide reform and maintenance basis and data support for the municipal administrative department,which is of great significance for improving the ability of urban storm sewer system to withstand rainstorm and the construction of sponge cities.