| Aiming at the deficiency of the existing design flood analyzing methods in China, JC Method is introduced in this paper, also the process to determine region composition of design flood and the method to calculate flood flux probability distribution of reservoir downstream are discussed. At last, the thought presented are validated by the given case study, it is showed to have good inference for calculating, analyzing and judging the design flood project of reservoirs. The main contend are as follows:(1)Summing up all existed ideas of analysis of design flood, also, the characteristics and developing trend of design flood in our country and other countries are analyzed. On based of compare and estimate, the shortage of interrelated theory used in our country are pointed out(2)It is analyzed systemically that the region composition and change about different level flood about upstream valley of Huanghe, encounter rules of flood peak flow of anabranch and main river, and region distribution law of rainstorm, so, it provide gist for research of reservoir's design flood.(3)The probabilistic design conception on li mit state was introduced, also, the theory and model of using the JC method to co mpute both single reservoir's and cascade reservoirs'design flood was studied, that is defining the flood volu me in so me period of ti me of design section as carryin g capacity (or ability to stand against destroy), and the volume of design frequency in the same ti me as syst em load, so as to set up the li mited state, then calculating by that state the composition and wrecked probability, which is just the risk.(4)Because of the impact of upperstream reservoirs to the downstream's flood probability distribution, both design flood and its ho mologize flood regulation regular in reason ascertain will all be affected. In this paper, as ulti mat e risk to be coincident with probability at physical nature, the atte mpt of applying JC method to flood probability distribution of reservoir's downstrea m is analysed, and also, it isproved to be practicable with examples. |
