The Research Of Hydraulic Calculation Of Town Watercourse Based On Reliability

Cause of the advance of. urbanization and the promotion of life standard, people claim higher quality of the water circumstances. The integrated function of city watercourses changes. Not only the basic functions as flood prevention, water drainage, storage and ship-canal, but also ecological, landscaped, rested and resorting functions are demanded. Both basic and additional functions should be considered when scheming the town channel sections. Calculating and designing the flow rate is the first issue of channel-renovation.The current methods of hydraulic calculation include design calculation of flow rate and dimensions calculation of city channels are analyzed in this thesis.It is demonstrative of problem that is the calculation result of the method regarded flood prevention as the main function is different from the result of the method regarded drainage as the main function when the town channel has flood prevention and drainage functions in the hydraulic calculation methods of small basin town channel. And many uncertain factors of the hydraulic calculation are not considered in both of the two methods.The reliability theory is used to analyze and quantify these uncertainty factors, and a hydraulic calculation model based on reliability has been built up in this thesis. Then to a design example as the town watercourse in Pengzhou City, JC method, and Monte-Carlo method are adopted to calculate the reliability of every main section of the watercourse, bound estimation method is adopted to calculate the reliability of the whole watercourse system . The result of calculation shows that the reliability of the watercourse designed with definite value design method is low. Then the reliable target index of the channel probability limit design is put forward, and the partial factors of corresponding to them are calculated. Finally, the probability limit state hydraulic calculation of watercourse is carried on with expected reliability index method and partial factor expression method for example, and the usability of this model has been tested.