海口红黏土的结构性本构模型研究  

Study of structural constitutive model for red clay in Haikou

作　　者：吴小锋[1] 李光范[1] 胡伟[1] 王晓亮[1] 

机构地区：[1]海南大学土木建筑工程学院,海口570228

出　　处：《岩土力学》2013年第11期3187-3191,3196,共6页Rock and Soil Mechanics

基　　金：国家科技支撑计划课题(No.2013BAK05B03);海南省自然科学基金项目(No.513144)

摘　　要：土体结构性的数学模型是21世纪土力学的核心问题。由于土体微观结构的变化造成了重塑土与原状土的力学特性上的差异。采用应变型和应力型结构性宏观参数来表征这种微观结构的变化,同时将应变性结构性参数引入到等向固结过程中去,用以描述常规三轴试验中剪切前的等向固结过程以及剪切时球应力对结构性土体的影响。实现应变型和应力型结构性宏观参数对整个三轴剪切过程的描述。修正剑桥模型对正常固结重塑黏土的三轴压缩试验能做出准确地描述,但对超固结黏土及原状土,即具有结构地土体,则不能给出准确地描述。将应变型和应力型结构性宏观参数引入到修正剑桥模型中,实现修正剑桥模型的结构化。该结构性修正剑桥模型参数的确定方法与常规修正剑桥模型参数的确定方法相差不多,只不过多了球应力与土体结构性体应变的关系式、偏应力与土体结构性广义剪应变的关系式。经过数值模拟比较,结构性修正的剑桥模型能较好地反映原状土的结构性演化过程,能描述原状土结构的整个破坏过程,在多种应力路径下具有很好的预测作用。The mathematical model for structured soil is a key problem of soil mechanics in twenty-first century. Soil microstructure is the main reason which causes the differences between natural and remolded soils. Stress structural parameter and strain structural parameter were introduced to describe the change ofmicrostructure. At the same time strain structural parameter were introduced into the isotropic consolidation process to describe the effect of spherical stress on structural soil in the process of isotropic consolidation and shearing, which realized the description for the whole process of triaxial shear tests. Modified Cambridge model can make an accurate description for normally consolidated remolded clay in the triaxial compression tests, but failed to make the same precision for overconsolidated clays and intact soil, which had the structural characteristics. Then the strain and stress structural macro parameters were introduced into the modified Cambridge model to achieve structurization. The parameters determination methods for structured modified Cambridge model were similar with the conventional modified Cambridge model parameters determination, but more than the relationships between spherical stress and strain, deviatoric stress and soil structural generalized shear strain. Through numerical simulation, the structural modified Cambridge model well reflected the structural evolution of the intact soil, and described the whole failure orocess of structure on a variety of stress oaths for intact clay in Haikou.

关 键 词：应力型结构性参数 应变型结构性参数 修正剑桥模型 海口红黏土 

分 类 号：TU442[建筑科学—岩土工程]