试用模糊分析方法预报水库淤积上延

A Fuzzy Analysis on The Forecast about Headward Silting of Reservoirs

水库淤积上延问题具有模糊性质.可通过模糊分析来进行研究与预测.本文以淤积上延系数为分析对象,入库沙量、相对库容及入库水流特性为因子,以约30个水库的实测资料为样本,通过模糊关系合成对水库淤积上延程度作出预报.其拟合率达到90％以上.分析中的每一步骤,包括因子的选择、因子区间与对象区间的划分、隶属度的确定以及模糊运算等,均用电算进行了多方案比较与筛选.最后还得出了诸因子不同组合条件下的预报结果(表4).此后,可直接利用它进行预报,无须再重复模糊分析的各步骤.

The headward silting of reservoirs is an ambiguous phenomenon which can be studied in fuzzy mathematics rather successfully. In this pape. the headward silting coefficient E (Eq. (1), (2)) is chosen as the object in the fuzzy-set analysis, and the incoming sediment load G, the relative storage of reservoir S (Eq. (3)) and the incoming hydraulic characteristic K ,(Eq. (4)) are chosen as the independent factors (Eq. (6), (7), (8)). The samples used for calculating degree of subordination are the field data from about 30 reservoirs. Then, a preliminary forecast about headward silting of reservoirs has been given in the light of the fuzzy relationship synthesizing. The checking results express that the goodness of fit is over 90%. All of the steps in analysis, including factors selection, partition of factor intervals and object intervals, determination of subordination degree and fuzzy operation etc., are finished in computer. And finally, a table (Table 4) indicating all of the possible forecast results under the miscellaneous combinations of independent factors has been obtained. Hereafter, it needs only using this table for forecast simply without repeating any step in the aforementioned fuzzy analysis.