The Short Duration Design Rainstorm Pattern Research In Shenyang

Under the influence of global greenhouse effect,urbanization process,rain island effect and so on,in recent years,the phenomenon of urban waterlogging frequently occurs in major cities of China,which brings great threat to the development of cities,the enterprises production and the daily life of citizens.In May 2014,the Ministry of Housing and the China Meteorological Administration jointly issued the "Notice on revising the work of storm intensity formula" which require all localities to revised the urban storm intensity formula,subsequently "Urban rainstorm intensity formula preparation and design storm rain pattern determination technical guidelines" was issued which is not only require local to revise the storm intensity formula,but also made a request for rain pattern design.The traditional storm intensity formula only describes the rainfall.The rainfall process in the fixed duration is constant,but the formation of the surface runoff is not only influenced by the rainfall but also has a great relationship with the rainfall distribution.In this study,based on the opportunity of a new rainstorm intensity formula revise in our country,the rainfall pattern in Shenyang City were studied through a large number of raw materials have been mastered.Firstly,Mann-Kendall non-parametric test method,Mann-Kendall mutation test analysis and moment-level analysis were used to analyze the characteristics of rainfall trends in Shenyang for 64 years,it was indicated that the rainfall is showing a trend of decline.Based on the analysis of different months and seasons in the main city of Shenyang for 64 years,it was found that the monthly rainfall trend is basically consistent with that of seasonal rainfall trend through Mann-Kendall non-parametric test method,Mann-Kendall mutation test analysis.Secondly,according to the statistical rain pattern(Pilgrim&Cordery and Huff rain pattern),and the design rain pattern(Chicago rain pattern),three typical rainfall were chosen to study the rain pattern of Shenyang.At the end,the integrated rainfall distribution ratio of the three methods was given,and the rainfall accumulation process of the three methods was analyzed.Three rain pattern have their own characteristics,the design rain pattern easy to use,the statistical rain pattern closer to the actual rainfall,these rain pattern can be selected according to specific situation.The three rain pattern provide some basis for the design of rainwater pipeline parameters and rainwater regulation system in Shenyang,and provide reliable data and technical support for urban drainage and drainage design.