【摘要】 为了描述可控基质吸力下的非饱和土时效变形特征，提出一种考虑非饱和土基质吸力影响的弹黏塑性本构模型。新模型借鉴BBM模型对压缩特征曲线进行修正，给出非饱和土的压缩指数与基质吸力的关系函数，并将该指数引入到能描述土体超固结的下负荷模型，得到非饱和土的修正下负荷面；又以该下负荷面为参考屈服面，利用相对应力关系，建立了非饱和超固结土的弹黏塑性本构模型，并通过非饱和的三轴率敏性试验确定新模型中两个时效参数m′和c₀。结果表明：（1）模型能较好地表征非饱和土超固结比、基质吸力对其变形特征的影响；（2）由非饱和土的三轴率敏性试验确定的模型参数能较好地模拟其蠕变等时效变形。更多还原

【Abstract】 In order to describe the aging deformation characteristics of unsaturated soil under controlled matric suction, an elasto-viscoplastic constitutive model considering matric suction is proposed.The new model uses BBM model to modify the compression characteristic curve, and gives the relation function between the compression index and matric suction of unsaturated soil.The index is introduced into the lower load model which can describe the overconsolidation of soil, and the modified lower load surface of unsaturated soil is obtained.Taking the lower load surface as the reference yield surface, an elasto-viscoplastic constitutive model of unsaturated overconsolidated soil was established by using the relative overstress relation.The two aging parameters m’ and c₀ in the new model were determined by the unsaturated triaxial rate sensitivity test.The results show that:（1）the model can well characterize the influence of overconsolidation ratio and matric suction on the deformation characteristics of unsaturated soil;（2）The model parameters determined by the triaxial rate sensitivity test of unsaturated soil can better simulate the creep and age deformation.更多还原