Design and construction of the grout curtain for the Ermenek hydropower plant / Planung und Ausführung des Dichtschirms für das Wasserkraftwerk Ermenek

In order to create the grout curtain for the Ermenek hydropower plant in Turkey, grouting measures were designed in karstified limestone. Based on the geological model, detailed investigations were carried out in advance of construction into the location and nature of the anchoring of the grout curtain into impermeable rock. Eventually, the water head of about 220 m will be grouted from four grouting galleries arranged vertically above one another with a separation of 70 m in each case, and connected from the lowest gallery at a maximum 250 m deep into impermeable layer. The overall height of the grout curtain will thus be about 470 m and the area approx. 680,000 m². The design intends a single-row grout curtain with drillings spaced at 1.5 m, with denser spacing at some locations in the course of construction. In the immediate vicinity of the dam, the grout curtain is to have two rows for structural reasons, combined with a drainage curtain. Consolidation grouting in the foundation area of the arch dam will be carried out in the course of concreting. The injection pressures and the success criteria for each injection will be described.
Detailed investigations into the grout were performed for the implementation of the grouting measures. The determination of the injection steps and the closer spacing of the injection pattern required in places will be discussed, also regarding the karst features encountered.
The impounding of the 4,600 m m³ reservoir, which will take about 5 years, will be started while the dam is still being concreted.