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Ön yüzü beton kaplı kaya dolgu barajların sismik performanslarının irdelenerek tasarıma uygun kılavuz yöntemlerin geliştirilmesi

Concrete faced rockfıll dam (CFRD) is an increasingly favoured dam type in the world along with the RCC dams. The design procedure for CFRDs, based on past experience, was significantly questioned after the poor performance of a number of recently built systems. The performance of CFRDs under earthquake were deemed exquisite; however, this preposition is hard to verify due to the scarcity of CFRDs subjected to very strong ground motions. The significance of this study stems from the determination of the working principles of these dams and the factors affecting CFRD performance based on detailed analytical studies, in lieu of the empirical experience. All constituents of the system were modeled using detailed material models calibrated to laboratory experiments and the cracking of the face plate was investigated over the whole operation period including the first reservoir loading, seismic loading and creep of the fill. The results of the study show that the cracking on the plate is the primary reason for the seepage from these dams, not the openings in the joints commonly suggested in previous studies. The effect of the design parameters on the cracking pattern of the face plate was investigated and the rigidity of the rockfill and reinforcement ratio were determined to be the two most important factors determining seepage. The results of the detailed 3D analyses showed that crushing effects should seriously be considered for these systems under strong earthquakes. Soil-structure interaction effects were investigated leading to suggestions on simulations and modeling; the use of simple modeling techniques for simulation of sand-gravel fill dams on alluvium layers were shown to be misleading. Along with the contribution to the scientific literature with the publications within the project duration, the work conducted has led to a range of suggestions which can be used for modelling and design in the industry. It is believed that the procedure developed in the last part of this report is going to contribute to dam engineering in improving on empirical design procedures.