A Method for Designing Finger Drains and Assessing Phreatic Lines for Dams

M.C.N. Araújo, T.F. de Souza Júnior, M.N.B.Trevizolli, C.A. Teixeira, S.H.C.Teixeira, V.P. Faro

Article

Soils and Rocks, São Paulo, 41(3): 309-317, September-December, 2018 | PDF


Abstract

Finger drains are linear drains used to collect and conduct percolated water in embankment dams. They are arranged crosswise into earth dams, either permanently or as a technique to treat clogged filters. Given their easy operation, they are often applied in engineering practice, without the aid of specific dimensioning techniques in many cases. The aim of this paper is to propose a method for designing finger drains for earth dams, considering geometric and hydraulic characteristics (length, width, spacing, height and reservoir level). Moreover, the method allows estimating the phreatic line inside the dam. The method was based on data from small scale physical models and on numerical models, calibrated using the physical model results. Twenty-seven numerical models were developed by simulating seepage for different spacing between drains and lengths of drains, besides three reference numerical models with different lengths of drainage mat. The numerical modeling was validated using the results of four small-scale models processed with software Seep/W.


Submitted on August 22, 2017; Final Acceptance on October 2, 2018; Discussion open until April 30, 2019. DOI: 10.28927/SR.413309