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Mıcrostructural Modellıng Of The Tıme Dependent Behavıour Of Soft Clay
Increasing needs of modern societies combined with developments in science and technology entail a greater resource allocation for infrastructure projects. Therefore, the considerations of safety and economy need to be more optimally combined in today’s construction projects. In terms of design and construction of soil structures, this concern requires to understand and follow the fundamental soil behaviour more thoroughly. Clays as having the widest deformation range deserves special consideration on research projects aimed to understand fundamental soil behaviour. Recent research indicated that deformation rate has a vital role in defining stress-strain behaviour of clay soils. Only if the strain rate is included, the behaviour of clays can be defined by a unique relationship in terms of “stress-strain-strain rate ()”.
This mechanism can also be termed as the time dependency or viscoplastic behaviour of clays. Viscoplastic mechanism is attributed to the mechanisms involved at the micro scale and there is a surge of interest to this research area among the researchers. It is, however, known that there is no generally accepted theory or methodology that explains the viscoplastic mechanism at the micro-scale and gives clues which can be used to combine micro-behaviour with macro-behaviour.
The research work defined in this thesis aims to evaluate “stress-strain-strain rate” behaviour of clays by disclosing the mechanism involved at macro and micro scale. The ultimate aim is to induce the implications of micro-mechanic behaviour into constitute modelling. This research work constitutes of three stages each of which involves intensive theoretical experimental and numerical modelling work. These stages are; i) Application of a novel experimental program which involves a series of original techniques, ii) numerical analyses of experimental findings together with image analyses results, iii) Development of a constitutive model under the light of the findings of experimental and numerical work.