Geotextiles in Embankment Dams - Association of State Dam Safety ...

Appendix A—Case HistoriesFigure 4 – The original drained buttress section developed with the presumption thatthe borrow site would yield sufficient quantities of well graded fill. Note, thedrainage zone needs to be extended to a higher elevation than shown in anticipationthat the buttress will impede drainage from the face and elevate the phreatic surface.Figure 5 – Detail of the drained buttress, i.e. filter and drainage zone consisting ofASTM C 33 fine aggregate for concrete and the well graded fill comprising the massof the buttress. Note that the plans called for field locating pea gravel finger drainswithin the fine aggregate zone at the intersection of the buttress and the strippedoriginal embankment face where any concentrated seeps were encountered.A-11