Elasto-Viscoplastic constitutive model for natural clay and its application

点击翻译按钮获取中文摘要

In order to rationally analyze the deformation of natural clay deposits, it is very important to construct constitutive model for natural clay. For this purpose, firstly we have carried out several tests for natural clay, e. g. anisotropic consolidation test, undrained compression and extension tests by use of triaxial apparatus and torsional hollow cylinder tests under undrained condition. From these results, we have found the overconsolidation boundary surface (initial yield surface) and examined the variation of viscoplastic parameters in the constitutive model. Also, rate sensitivity and softening characteristics of sheer behavior have been clarified. By the triaxial tests results for the presheared sample, the effect of disturbance for the mechanical behavior was observed.From the triaxial test results on the samples with different inclination angle between the major principle stress plane and the horizontal bedding plane, it was found that the effect of structural anisotropy on deformation behavior is more marked than the b value in the overconsolidated Eastern Osaka clay.Considering the above mentioned experimental results, we have developed an elasto-viscoplastic model for clay which can describe the cyclic behavior and anisotropic characteristics of natural clay in the overconsolidated region. And we have discussed the problem of application of the proposed model to the real boundary value problem.