دانلود رایگان مقاله انگلیسی یک رویکرد ساده ارزیابی نشت با عنصر غیر قابل نفوذ سد های خاکی مرتفع - اشپرینگر 2018

Abstract

Internal erosion is the most common reason which induces failure of embankment dams besides overtopping. Relatively large leakage is frequently concentrated at defects of impervious element, and this will lead to eventual failure. The amount of leakage depends not only on integrity of impervious element, but also on dam height, shape of valley, shape of impervious element and water level in reservoir. The integrity of impervious element, which represents the relative level of seepage safety, is not easy to be determined quantitatively. A simple method for generalization of steady seepage state of embankment dams with thin impervious element is proposed in this paper. The apparent overall value of permeability coefcient for impervious element can be obtained by this method with reasonable accuracy and efciency. A defect parameter of impervious element is defned as an index to characterize seepage safety of embankment dams. It equals the ratio of the apparent overall value of permeability coefcient to the measured value in laboratory for intact materials. Subsequently, seepage safety of three dams is evaluated and the evolution of defect level of impervious element of dams is investigated. It is proved that the newly proposed method in this paper is feasible in the evaluation of relative seepage safety level of embankment dams with thin impervious element.

Summary and conclusions

A simple approach to calculating leakage through embankment dams with thin impervious element is proposed in this paper. By using this approach, dam height, shape of valley, shape of impervious element and water level in reservoir are taken into account. Then, the apparent overall value of permeability coefcient for impervious element can be obtained with reasonable accuracy and speed.

Defect parameter of impervious element is introduced to represent defect level of internal erosion. The defect parameter is defned as the ratio of overall value of permeability coefcient to laboratory test value for intact material.

The newly proposed approach and the concept of defect parameter are further applied in the case study. It is found that the proposed approach is feasible in seepage safety level evaluation of embankment dams with thin impervious element.