توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱Micro–polar Modeling of a Geogrid Reinforcement under Shearing Movement
نویسنده(ها): ،
اطلاعات انتشار: چهارمین همایش بین المللی مهندسی ژئوتکنیک و مکانیک خاک ایران، سال
تعداد صفحات: ۸
The behavior of a reinforced soil element including a rigid geogrid reinforcement in contact with granular soil is numerically investigated using elasto–plastic micro–polar (Cosserat) continuum approach. The main attention of paper is laid on the influence of micro–polar kinematic boundary conditions prescribed along the interface between soil and geogrid on the evolution and location of localized shear zone developed inside granular soil body. The obtained numerical results are qualitatively compared with those of experiments. In this regard, homogenous distribution and a certain periodic fluctuation of rotation resistance of soil particles interlocked with geogrid cells are assumed along the interface. The FE results demonstrate that the interaction between granular soil and geogrid reinforcement has significant influence on deformation field inside the soil close to geogrid.<\div>

۲Shear Band Formation in Biaxial Compression Test
نویسنده(ها): ،
اطلاعات انتشار: چهارمین همایش بین المللی مهندسی ژئوتکنیک و مکانیک خاک ایران، سال
تعداد صفحات: ۸
Shear localization phenomenon is not simulated properly within the framework of classical continuum due to the lack of material characteristic length. Consequently, the numerical solutions of rate boundary value problems exhibit mesh sensitivity and become mathematically ill–posed. It is widely accepted that post–bifurcation behavior can be well captured by micropolar (Cosserat) continuum to eliminate the limitations of classical continuum in problems involving shear localization. In this paper, an elasto–plastic micro–polar (Cosserat) model is proposed to capture the formation of shear band in biaxial compression tests. The model takes into account Cosserat rotations and couple stresses via the mean grain diameter as characteristic length. Applications of the model in simulations of biaxial compression tests with finite element method in Updated Lagrangian (UL) formulation are presented. Particular attention is paid to the effects of mesh size, mean grain diameter and boundary condition on the evolution of shear localization. It is found that prescribed boundary condition have strong influence on the pattern of shear banding in biaxial compression test. The numerical results are compared with those of experiments. Qualitative agreement is observed between numerical predictions and experimental measurements.<\div>

۳A Numerical Study on Localized Deformation Pattern in Granular Soil behind Retaining Wall
نویسنده(ها): ،
اطلاعات انتشار: چهارمین همایش بین المللی مهندسی ژئوتکنیک و مکانیک خاک ایران، سال
تعداد صفحات: ۹
The present paper investigates the development of shear localization inside granular soil supported by a retaining wall under active movement. Micro–polar (Cosserat) continuum approach is utilized to overcome the numerical difficulties of localization modeling encountered in the classical continuum mechanics. For description of the mechanical properties of granular soil, the Lade’s single hardening constitutive model enhanced by polar terms is used which takes into account particle rotations, micro–curvatures, non–symmetric shear stresses, couple stresses and internal length. The attention is paid to the influence of different modes of wall movement on the pattern of shear localization developed inside granular body behind the wall. The FE results are compared with analytical solutions and experimental observations. It is shown that the obtained numerical predictions provide reasonable qualitative agreement with the corresponding laboratory model tests. However, there are substantial differences between FE results and analytical solutions.<\div>
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