Atilla ÜNSAL, Atila SEZEN

Kumların drenajlı davranışının mikromekanizmaya bağlı olarak endokronik teori kapsamında modellenmesi

Mikroskobik değişkenlerin ve bunların şekil değişimi ile birlikte değişimlerinin belirlenmesi ve tanecikli ortama ait bu değişkenlerle sürekli ortam arasındaki bağlantının sade ve basit bir şekilde kurulması oldukça önemli ve büyük bir sorundur. Bu çalışmada, mikroskobik sürece ait içsel durum değişkenlerine dayalı olması ve sürekli ortamda tanımlanabilen bünye ifadelerine olanak vermesinden dolayı, endokronik teorinin olanakları geliştirilmeye çalışılmıştır. Zemin davranışının mikro ölçekte gerçekleşen sürecinin anlaşılması amacıyla, ilkin, hangi mikro ölçek değişkenlerinin zemin davranışını izah edebileceği tartışılmıştır. Daha sonra, zeminlerin şekil değiştirmesinin mikromelcanizması bir seri sava bağlı olarak izah edilerek, endokronik bünye ifadeleri elde edilmiştir ve önerilen modelin öngörü kapasitesi drenajlı üç eksenli basınç koşulları için irdelenmiştir.

Micromechanism-based endochronic modeling of sand behavior

The observed macroscopic properties of soil behaviour is mainly the manifestation of microscopic mechanism during deformation. Consequently, modeling of soil behaviour should ideally be based on the microscopic process determining the behaviour. But, observation and determination of the related microscopic properties and parameters is a difficult and time consuming process. Besides this problem, the link between the microscopic paniculate medium and continuum medium is an another problem and usually very complex relations have been proposed. One of the main advantage of endochronic theory is its fundamental philosophy which bases the phenomenology of the soil behaviour on the internal state variables that need not to be observed. The first part of this study focuses on the arguments related with micro variables that are supposed to be controlling macroscopic soil behaviour. Jt is aimed to determine the important micro variables and consequently to propose a general hypothesis about the micromechanism of deformation process in sands. Regarding to the perspective gained by the proposed hypothesis for the micromechanism of soil deformation, constitutive relations are obtained and the predictive capacity of the proposed model is investigated by modeling of drained triaxial tests conducted on sands. It has been seen that stress-strain behaviour can well be modelled while observed softening phenomena still needs to be more clearly formulated in the model.

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