ÖzBu çalışma da, sert ve yumuşak alüvyon temeller üzerine oturan 30m yükseklikteki homojen kil dolgu bir barajın, memba ve mansap şevlerinin stabilitesine, şev eğimlerine ve temel kazılarının derinliğine alüvyon özelliklerinin etkisi araştırılmıştır. Analiz sonuçları baraj güvenliği ve kazı-dolgu maliyetleri açılarından değerlendirilmiştir. Çalışma neticesinde, alüvyonun sertliği azaldıkça, kayma yüzeylerinin alüvyona kadar nüfuz ettiği ve minimum güvenlikli kayma yüzeylerinin daha derin ve büyük olduğu görülmüştür. Bu nedenle, bu tür alüvyonlarda baraj altında kazılarının daha derin yapılmasının daha sağlıklı olacağı ve ayrıca dolgu şevlerinin de daha yatık yapılmasının uygun olacağı sonucuna varılmıştır. Alüvyonun sertliği arttıkça şev kayma yüzeyleri sığ kalarak alüvyon zemine nüfuz etmemekte, alüvyon temelin yüzeyine yakın ve baraj dolgusunun içerisinde kalmaktadır. Bu nedenle, sert alüvyon temeller üzerine oturan baraj dolgularında temelde az bir alüvyon kazısı yapmanın yeterli olacağı sonuncuna varılmıştır. Ayrıca, baraj dolgusunun memba mansap şev güvenliğinin, yumuşak alüvyon zeminlerde olduğunun tersine, sıkı alüvyon zeminler üzerine oturan homojen kil dolgu barajlarda daha fazla olduğu görülmüştür.

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In this study, effects of berm heights, excavation slope gradients and groundwater depths on the stability of designed excavations as well as variations on the safety factors of the excavation slopes are investigated. In the study, 3 different berm heights (5m, 10m and 15m) and 2 berms usually preferred and faced at the slope excavation applications were taken into consideration. So, for instance, for a 10 m berm height, total slope height to be analyzed will be a 30m high due to for 2 berms. In addition, depending on these 3 different berm heights (5m, 10m and 15m), 3 different slope excavation gradients (450, 550 and 650) were also defined in the modeling. Then, for these 9 different slope excavation designs, 3 different groundwater depths were also additionally attained in the analyses. Numerical seepage analyses were performed on totally 27 different modal types. Location of phreatic water seepage lines and pore water pressure values as well as safety factors of the excavation slope failure surfaces were analyzed depending on berm heights, excavation gradients and groundwater locations for 27 different excavation and slope scenarios. This study showed that when berm heights are increased, then safety of the slope excavations is decreased.

It is well known that the construction of a wider impervious core for earthfill dams provides greater piping resistance and a greater resistance to earthquakes, which can cause internal cracks within the core. Also, designing a wide core can minimise construction defects. However, the core width and its location in earth or rockfill dams are actually determined by consideration of factors such as the type of material, piping resistance, geological features, cracking, earthquake considerations and stability requirements. In this study the influence of thickness of the impervious core and the magnitude of the earthquake coefficient on the stability of both upstream and downstream slopes of the Kızılca dam are presented. Because the clay core will be a compacted fill and the characteristics of the clay core material are very good, with high dry unit weights and permeabilities less than 10−10 m/s, hopefully there will be no problems of piping. There will be no seepage or stability problems with the geology of the Kızılca dam site; therefore the problem is only to determine the ultimate choice of the impervious core slopes from the point of view of maintaining the optimum stability of the Kızılca dam's outer slopes, to construct an economical impervious fill, and to determine whether or not the alluvium under the dam has to be removed. That is why, using conventional sliding surface methods, the stability analysis for sudden drawdown and full impounded water-level cases was performed for different core slopes with IV : IH and IV : 0·5H.