考虑统一强度理论的黄土二元介质模型研究

Binary-medium model for loess considering unified strength theory

针对饱和黄土的本构模型进行研究,引入统一强度理论,确定了应力不变量形式的统一屈服准则。分析了黄土的强度构成,解释了黏聚强度和摩擦强度变形中发挥过程,结合二元介质模型基本理论,确定了黄土的胶结元和摩擦元两种参考介质的模型以及破损参数,采用等效应变原理,建立了黄土的二元介质本构模型,并分析了模型参数的确定方法,采用黄土的三轴试验对所建立的本构模型进行验证,并与统一弹塑性本构模型进行比较分析,进一步分析了所建立二元介质模型的适用性。

The strength deformation characteristics of loess are complicated.It is important for engineering construction to accurately predict the mechanical behavior of loess.The constitutive model for loess is studied.The unified strength theory is introduced.A unified yield criterion in terms of stress invariants is determined.The strength constituent of loess is identified.The evolution of cohesion strength and friction strength is explained during the deformation.Combining with the basic theory of binary medium model,the models for the cementation and friction mediums of loess are established,as well as the damage parameters.Based on the principle of equivalent strain,a unified binary medium constitutive model for loess is proposed.The determination of model parameters is analyzed.The constitutive model is verified by the triaxial tests on loess.The comparison between the proposed model and the unified elastoplastic model is conducted.The applicability of the binary-medium model is further analyzed.