考虑软土流变和损伤的比奥固结有限元分析

软土的变形受到流变性和结构性这两种基本特性的双重影响,计算分析中应予以同时考虑。本文基于已有的软土流变模型,提出了一种可以同时考虑这两种特性影响的软土粘弹塑性损伤本构模型,并能定量的描述原状土结构性逐步破损过程和反映施工预处理引起的初始损伤对于土体后期变形的影响。将该模型耦合Biot固结理论,导出了有限元求解方程并介绍了求解方法,编制了相应的有限元程序。结合工程实例,采用本文模型和不考虑软土流变及损伤影响的双屈服面模型分别对路基变形进行对比计算分析,验证了模型的合理性,揭示了软土地基考虑流变性及其结构性损伤在固结变形中的综合作用。

FEM analysis of Biot's consolidation for soft soil rheology and damage

Deformation of soft soil was impacted by it's two basic characteristics: the behaviors of rheology and structure.The two should be considered at the same time in calculating analysis.Based on the existing rheological model of soft soil,a viscoelastic-plastic-damage constitutive model considering the two behaviors was proposed.It can also quantitatively describe the gradual damage process of the undisturbed soil's structure and reflect the impact due to the initial damage caused by construction pretreatment on the latter deformation of soft soil.The model coupled with the Biot's consolidation theory,finite element equations were derived and a solving method was introduced.Combining an engineering example,this model and the double yield surface model not considering the rheological and damage effects were compared on the roadbed deformation analysis,and the reasonableness of the model proposed by this article was verified.Comprehensive roles were explored in the process of soft ground's consolidation deformation considering rheological and structural damage behavior.