关键词: 堤坝, 渗流, 复变函数, 数值积分

Abstract:

According to Numerov’s theoretical solution, the additional length of seepage path of upstream slope of dams and levees on impervious strata is direct propotional to the upstream water depth H, and inverse propotional to the ratio of the seepage quantity of unit width to the permeability coefficient q/k. On the basis of the equation of phreatic line in Numerov’s theoretical solution, coefficients and are calculated by Simpson’s numerical integration method. For confined flow, the corresponding additional length of slope is directly propotional to the thickness T of permeable strata only; and not relate to H and q/k, i.e. . In accordence with the calculating results, . Why the additional length is inversely propotional to q/k, the reason is explained. The method of calculating has extended to the condition that under the slope an overburden is located. All the formulae of additional length are analysed and compared each other. Finally, an example is given to relate the process of calculating the seepage flow of dams with the additional length .

Key words: dams and levees, seepage, function of complex variable complex variable, numerical integration