川西崩坡积混合土循环荷载下非饱和动本构模型  

Study on constitutive model of unsaturated Chuanxi talus mixed soil under cyclic loading

作　　者：崔凯[1] 李永奎[1] CUI Kai LI Yong-kui(Department of Civil Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031, China)

机构地区：[1]西南交通大学土木工程学院,四川成都610031

出　　处：《岩土力学》2017年第8期2157-2166,共10页Rock and Soil Mechanics

基　　金：国家自然科学基金非饱和崩坡积混合土动力特性的细粒效应与累积变形研究(No.41572245)~~

摘　　要：在川西地区,由砂砾石与黏土颗粒构成的混合土路基经常会发生沉降变形问题。对于交通荷载作用下土体中的累积变形,可通过建立循环荷载作用下的动本构模型进行描述。在边界面弹塑性理论的框架内,综合考虑崩坡积混合土非饱和状态和细颗粒含量两大主要影响因素,结合能比较真实描述非饱和土体湿陷性能的LC(loading-collapse)屈服曲线,同时基于可移动映射中心的映射准则,采用经典的修正剑桥模型作为塑性势方程,构建了混合土的非饱和动本构模型,其参数可通过拟合或常规试验获得。通过与试验结果进行对比,该模型不仅可以较好地反映非饱和混合土在静载和循环荷载下的力学特性,而且能够真实地预测土体在加、卸载过程中的滞回特性。其结果可为川西混合土路基沉降变形预测提供理论依据。In the Western Sichuan area, settlement or deformation problems often occur in embankments consisting of the mixed soil containing sandy gravel and clay particles. The accumulated deformation under traffic loads could be described by the dynamic constitutive model under cyclic loading. The proposed model uses the mapping rule of mobile mapping origin and integrates the loading-collapse yield criterion within the framework of elastic-plastic bounding surface model. Modified Cambridge model was introduced to define plastic potential equation. Saturation and fine particle content are considered as two main influencing factors. The model parameters are obtained by fitting measured results. Comparisons between experimental results and model simulations show that the elaborated model is capable of describing the unsaturated loess behaviors under static loading and cyclic loading, and predicting the hysteretic properties during both loading and unloading. This model provides theoretical basis for settlement prediction of mixed soil subgrade in the Western Sichuan area.

关 键 词：非饱和土 崩坡积混合土 循环荷载 细颗粒含量 动本构模型 

分 类 号：TU432[建筑科学—岩土工程]