土のダイレタンシー特性を考慮したFEM非線形解析

概要

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Dilatancy is one of the most important characteristics of soils, which means volumetric strain due to deviatoric stresses. So the authors recognize it very significant to consider the dilatancy characteristics accurately for the analyses of soil engineering problems by Finite Element Methods. However, most of the convensional F. E. Methods adopting incremental stress-strain relationships of isotropic elastic materials (called Isotropic FEM) have not been able to consider dilatancy under multi-axial stress conditions. The authors have been carrying out a series of the studies on the development of nonlinear F.E. Analysis which can consider dilatancy characteristics of soils completely. As the results of these studies, one F.E. Method is proposed in this paper, which adopts incremental stress-strain relationship of anisotropic elasto-plastic material (called Anisotropic FEM). The following conclusions have been drawn after comparison of the numerical results of two F.E. Methods under a few boundary conditions. 1. Isotropic FEM cannot analyse the dilatancy characteristics of the granular materials, because a stiffness matrix becomes negative-valued when extensional dilatancy is initiated. 2. Anisotropic FEM can analyse the dilatancy characteristics of soils under both multi-axial stress conditions and rotation of the principal stress axis.
長崎大学工学部,Faculty of Engineering, Nagasaki Universityの論文