季冻区草炭土非线性K-G模型试验研究

Experimental study on nonlinear K-G model for turfy soil in the seasonal frozen zone

摘要:

季冻区草炭土是沼泽环境中植物残体在氧化分解作用下，堆积形成的含有大量未分解纤维残体的特殊土。草炭土纤维及其含量对其强度和变形特性具有重要影响，目前考虑纤维含量对草炭土强度和变形特性影响的本构关系研究还相对匮乏。K-G本构模型因其模型参数与土的体积模量和剪切模量能建立直接联系，因此在岩土工程非线性理论和数值计算分析方面广泛应用。以不同纤维含量的草炭土为研究对象，进行三轴剪切试验，研究了草炭土的应力应变曲线，得到了草炭土非线性K-G模型参数，分析了各模型参数随纤维含量的变化规律，建立了模型参数与纤维含量之间的线性函数关系。对实际公路工程建设具有一定的指导意义。

关键词:季冻区草炭土;纤维含量;非线性K-G模型;模型参数

Abstract:

Turfy soil in the seasonal frozen area is a special soil containing a large amount of undecomposed fiber residues formed by the accumulation of plant residues in the swamp environment under the action of oxidation and decomposition. The turfy soil fiber and its content have an important impact on the strength and deformation characteristics of turfy soil. At present， the research on the constitutive relationship considering the influence of fiber content on the strength and deformation characteristics of turfy soil is relatively scarce. The K-G constitutive model is widely used for nonlinear theoretical and numerical calculation analysis in geotechnical engineering because the model parameters can be directly connected with the bulk modulus and shear modulus of soil. Taking turfy soil with different fiber content as the research subject， the stress-strain curve of turfy soil was studied by triaxial shear test， and the nonlinear K-G model parameters of turfy soil were obtained. The linear function relationship between model parameters and fiber content was established. It can provide some guidance for actual highway construction.

Key words:turfy soil in the seasonal frozen zone;fiber content;nonlinear K-G model;model parameters