The Research Of Storm Intensity Formula In Boai Country

The greenhouse effect makes the global climate change,which leads to the change of the duration,intensity and frequency of extreme precipitation events.Extreme precipitation is an important cause of urban waterlogging.The calculation of rainstorm intensity formula,which is the basis of solving waterlogging effectively,is the most important part of urban municipal construction services.As the guidance of urban drainage system,rainstorm intensity formula can avoid the loss caused by urban waterlogging to a large extent and protect the ecological living environment of the people.Boai County,as a district and county without the formula of rainstorm intensity,can only use the formula of rainstorm intensity in Jiaozuo area in the design and calculation of drainage engineering,so there must be economic and security problems.As the basis of municipal engineering planning and construction,the formula of rain intensity directly affects the urban drainage system,and its calculation results determine the effectiveness and safety of the drainage engineering.It is very important to reasonably deduce the practical formula of rainstorm intensity by using the local rainfall record data of Boai county.In this paper,the statistical samples of rainstorm data in Boai County are established by using the method of annual maximum sampling,which is mainly divided into two aspects:the adjustment of frequency curve and parameter estimation,and the deduction of rainstorm intensity formula.The error and difference rate of nine groups of rainstorm intensity formulas are compared and analyzed,and the final results are obtained.Based on three models(Gumbell model,Pearson-? model and exponential model)to fit the samples,the overall acceptance degree of each model to the experience points can be determined by comparing the total errors of each curve:Gumbell model>P-3 model>exponential model.The parameters of each model are solved and analyzed by three methods(Marquart method,Gauss-Newton method and least square method).According to the requirements of relative error and absolute error in the code,the requirements of less than 5%are finally met:using Gumbell distribution curve to adjust the frequency,using Marquart method to solve the parameters of the storm intensity formula(expressed as formula I);Frequency adjustment of the number distribution curve and the formula of rainstorm intensity by using Marquart method to solve the parameters are described as Formula ?.Through the analysis of the difference rate between formula I and formula ?,and considering the economic safety synthetically,it is concluded that formula I can better guide practical engineering.Formula ?:???Based on the original measured rainfall data,the formula uses the annual maximum method to select statistical samples,the Gumbell distribution curve model fitting and collating,and the Marquarte method to solve the relevant parameters.To sum up,in the municipal engineering of Boai County,the formula of P=2-20a is recommended considering economic factors,while in the hydraulic engineering,the formula of P=2-100a is recommended considering safety factors.