Browsing by Author "Firew, Tezera"

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    Constitutive Model for the Red Clay Soils of Addis Ababa
    (Addis Ababa University, 2003-07) Firew, Tezera; Boled, Girma(PhD)
    Key words: constitutive equations, strains, stress, elastic-plastic theories. An associative constitutive model originally developed by C. S. Desai based on rateindependent elastoplasticity concepts is validated for the Red Clay Soils of Addis Ababa. The basic concept of the model used herein was proposed and developed by Desai (1980). The yield function is expressed in terms of the state of stress, while the evolution or strain hardening process is characterized by using internal state variables such as the irreversible strain. Laboratory tests are conducted to determine the material constants. The material constants that are associated with the model are found based on four different states of a material deformation process: the elastic, plastic accompanied by hardening, phase change from contraction to dilation and the ultimate state. The model is then validated by comparing predictions with laboratory tests from which the constants were found, and also with tests not used for finding the constants. Comparison of observed and predicted response show that the model yielded predictions that compared remarkably well with the observed behavior.