EARTHQUAKE SAFETY EVALUATION OF ATATURK DAM

case the dynamic shear moduli approach the more unfavourable upper bound values, the total
lowering of the core top during the MCE could become as high as 2.3 m as a result of drops of
about 1.5 m and 0.8 m due to sliding movements towards the upstream and downstream sides,
respectively.
12. The ground motion also produces general settlements due to the vibration-induced densification of
the embankment materials, which was estimated as 0.5 m.
13. The total drop of the elevation of the core top caused by the MCE could approach the order of
3 m, when the effects of both the earthquake-induced sliding movements along the slopes and the
general seismic settlements due to the densification of the dam materials are considered. Hence,
the minimum freeboard with respect to the core top should not be less than 3 m. In other words,
the minimum level of the top of the core should be at least 545 m a.s.l., as the maximum operation
reservoir level is 542 m a.s.l.
14. The relatively wide filter zones provide an effective first line of defence against the development
of concentrated leakage through the dam after the earthquake. Moreover, the dam core consists of
highly plastic clay, which is a good core material that is resistant to erosion even in the worst
conditions of cracking and leakage. The minimum filter width at the location of a sliding surface
after the MCE would not be less than about 6 m, which should be adequate to ensure that the filter
zones continue to perform satisfactorily in the critical period following the earthquake.
ACKNOWLEDGMENT
The authors are grateful to DSI for permitting publication of the paper. The investigations and studies
described in this paper were carried out in cooperation with DSI and Dolsar Engineering Ltd. The
contributions of other experts, who have participated in this project and are not listed explicitly, are
greatly acknowledged. The opinions expressed in this paper are those of the authors and are not
necessarily those of DSI.
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