YIELDING CHARACTERISTIC AND NON-COAXIALITY OF TOYOURA SAND ON p′-CONSTANT SHEAR STRESS PLANE

SOILS AND FOUNDATIONS

TAKAFUMI NAKADA¹  JIRO KUWANO³  SHINYA TACHIBANA³  HIROSHI OHKAWA² 

[1] Obayashi Corporation;National Police Agency, Government of Japan;Geosphere Research Institute, Saitama University

关键词: anisotropy;    (elastic modulus);    (isotropic hardening);    laboratory test;    (non-coaxiality);    plasticity;    sand;    stress history;    torsional shear;    yield;    (IGC: D6);   

DOI  :  10.3208/sandf.51.179

学科分类：建筑学

来源: Japanese Geotechnical Society / Jiban Kogakkai

【 摘 要 】

References(46)Cited-By(4)In order to investigate the deformation characteristics under a wide selection of stress history, ten series of stress probing tests on p′-constant shear stress plane on dense Toyoura sand are conducted by using hollow cylinder apparatus. This paper presents yielding behavior and non-coaxiality of Toyoura sand obtained from the tests. The stress probing tests consist of ten series of shearing tests each of which starts from systematically chosen individual initial stress point. Each initial stress point is subjected to load-unload stress history. The yielding characteristic is interpreted by means of a concept of multiple yield surfaces model which has three yield surfaces representing linearly elastic behavior limit, commencement point of rapid development in plastic strain and elasto-plastic range. As a result, an experimental evidence of the isotropic hardening, i.e., isotropic expansion of yield surface, induced by anisotropic loadings is obtained. This is what was tacitly assumed in the application of plastic flow rules. However, misalignment of directions between principal stress and principal plastic strain increment is observed. Moreover, plastic strain increment direction is found to be influenced by the given stress increment direction. These facts suggest the non-coaxiality between stress and plastic strain increment due to shear stress increment, even during monotonic loading with isotropic hardening. The plastic strain increment direction diverges from the normal direction to a surface which is a circle with its center nearly at the origin on p′-constant plane and which passes through the current stress point.

【 授权许可】

Unknown