Seepage control design of the Arkun dam in Turkey

The main dam in the Arkun project is a concrete face sand-gravel fill dam (CFSGD). As sand-gravel fill materials, which are not free draining, were used for the major part of the dam body, the owner investigated the seepage behaviour of the dam in detail and considered extreme load cases, which are not usually part of standard dam analyses. The seepage analysis focused on conditions where the cut-off wall shows leakage and/or the face slab suffers from cracking. A simple modelling method determining the steady-state conditions and considering saturated material properties was considered to be sufficient in consideration of the inaccuracy in predicting the location and type of potential leakage. It was proven that the seepage control design of the dam is able to withstand hypothetical extreme load cases, for which the first barrier suffers total failure.