论土体本构关系对应力路径的依赖性  

DEMONSTRATION ON DEPENDENCY OF CONSTITUTIVE RELATIONS OF SOILS WITH STRESS PATHS

作　　者：王靖涛[1] 周葆春[1] 

机构地区：[1]信阳师范学院土木工程学院

出　　处：《岩石力学与工程学报》2008年第S1期2669-2674,共6页Chinese Journal of Rock Mechanics and Engineering

摘　　要：在进行不同应力路径下黏土和砂土的三轴压缩试验的基础上,根据塑性体应变与塑性剪应变之间的相互作用原理,在理论上证明,岩土塑性变形对应力路径的依赖性确实是存在的,并且它是塑性体应变与塑性剪应变相互作用的综合表现;应力路径相关性不仅包括压硬性效应,而且还包括剪胀性。3种不同应力路径下黏土和砂土的三轴压缩试验结果表明,剪切和体积屈服面随应力路径变化而发生整体转动,同时伴随着应力空间中屈服面尺寸的变化;这种现象称为旋转硬化;对在循环荷载或大应力转折条件下屈服面发生旋转的机制进行分析,阐明这种旋转硬化是应力路径影响的结果,其本质上是塑性体应变与塑性剪应变相互作用的反映。Based on the triaxial compression tests of clays and sands under different stress paths,it is theoretically proven according to the principle of interaction between plastic volumetric and shear strains that the constitutive relations of soils are dependent on stress paths,and the dependency of stress path is the combination of effects of the interaction between plastic volumetric and shear strains. The dependence of stress path includes not only the effect of pressure sensitivity but also shear-induced dilatancy. The results of triaxial compression tests for clays and sands under three different stress paths show that the shear yield surfaces and volumetric yield surfaces rotate with the change in stress paths. At the same time,the sizes of yield surfaces in the stress space vary with stress paths. This phenomenon is called rotational hardening. The mechanism of yield surface rotation is analyzed and it is explained that the rotational hardening is resulted from the dependency of stress path,which is essentially a reflection of the interaction between plastic volumetric and shear strains.

关 键 词：岩土力学 土体本构关系 应力路径相关性 相互作用原理 循环荷载 旋转硬化 

分 类 号：TU43[建筑科学—岩土工程]