دانلود رایگان مقاله انگلیسی تجزیه و تحلیل اثر تاخیر نشت سد خاکی بر اساس اطلاعات متقابل به تاخیر افتاده - الزویر 2018

ABSTRACT

Environmental variables, such as the upstream level, significantly affect the embankment dam seepage lag time. The lag effect should, therefore, be given adequate consideration when determining the saturation line and establishing a mathematical model for seepage. At present, however, the lag time is mainly estimated qualitatively. A method for analyzing the seepage lag effect is presented herein based on the mutual information principle of information science theory, wherein the upstream water level is considered an information source and water level of the seepage pressure is considered an information function point. The method explores application of the directed information transfer index (DITI) of mutual information in order to establish an information transfer model between seepage levels of measurement points and upstream levels of the embankment dam. Furthermore, an extreme value of the DITI function is adopted as the judging criterion to determine the lag time of the influence of the upstream level on corresponding seepage levels. Results obtained through analysis of an engineering case study, demonstrate the effectiveness and feasibility of the proposed method.

5. Conclusion

The lag effect in the seepage of an embankment dam is influenced by environmental variables, such as the upstream water level. This lag effect has an important influence on health diagnosis and safety monitoring of embankment dams. However, the lag time is primarily estimated qualitatively at present because of a lack of quantitative analysis methods. This paper proposes an analysis method for seepage lag based on DITI estimated by exploring the mutual information principle with the upstream water level considered as an information source and the water level of the seepage pressure considered as an information function point. The proposed method provides a new approach for quantitatively determining lag times of the water level of the seepage pressure in embankment dams with respect to the upstream water level. The proposed method has obvious advantages, particularly in the case of a weak lag that typically exists between the water level of the seepage pressure and upstream water level. Our analysis of the model demonstrates that the proposed method is reasonably feasible and effective for use in the said application. In addition to determining the lag time of the seepage in embankment dams, the proposed method can also be employed for lag effect analysis of other related variables with hysteric characteristics. Marginal distribution is the basis of mutual information calculation. In this study, the Gaussian kernel function was used to estimate the marginal distribution of the water level of the seepage pressure and the upstream water level. However, determination of the actual marginal distribution of seepage pressure and upstream water level require further research.