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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。
Soil structural mathematical model is the core issue of soil mechanics in the 21st century. Due to the change of soil microstructure, the difference of mechanical properties of remolded soil and undisturbed soil is caused. The strain and stress-type structural macroscopic parameters are used to characterize the microstructural changes, and the structural properties of strain are introduced into the isotropic consolidation process to describe the isotropy before shearing in a conventional triaxial test The effect of consolidation process and ball stress on structural soil during shearing. Realize the description of the whole triaxial shear process with strain and stress type structural macroscopic parameters. The modified Cambridge model can accurately describe the triaxial compression tests of normally consolidated reconstructed clay. However, accurate descriptions of overconsolidated clay and undisturbed soil, ie structured soils, can not be given. The strain and stress-type structural macroscopic parameters are introduced into the modified Cambridge model to realize the structural correction of the modified Cambridge model. The method of determining the parameters of the structural correction Cambridge model is almost the same as the method of determining the parameters of the conventional modified Cambridge model except that the relationship between the spherical stress and the structural strain of the soil mass, the deviatoric stress and the generalized structural shear strain Relationship. After numerical simulation, the structurally modified Cambridge model can better reflect the structural evolution of undisturbed soil, describe the entire failure process of undisturbed soil structure, and have good predictions under various stress paths.