黏土的结构性定量化表征及其弹塑性本构模型研究  

Structured quantitative characterization and elastoplastic constitutive model of clay

作　　者：李吴刚 杨庆[2] 刘文化[1] 杨钢[2] 孙秀丽[1] LI Wu-gang;YANG Qing;LIU Wen-hua;YANG Gang;SUN Xiu-li(School of Environment and Civil Engineering,Jiangnan University,Wuxi 214122,China;State Key Laboratory of Coastal and Offshore Engineering,Dalian University of Technology,Dalian 116024,China)

机构地区：[1]江南大学环境与土木工程学院,江苏无锡214122 [2]大连理工大学海岸和近海工程国家重点实验室,辽宁大连116024

出　　处：《岩土工程学报》2022年第4期678-686,I0005,共10页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(51639002,52009049)。

摘　　要：结构性可增强土骨架的稳定性,在相同的应力条件下,结构性土与重塑土相比可保持更大的孔隙比。从结构性土的形成过程出发,详细分析了结构性对土体变形特性的影响及变形过程中结构性的衰退规律,提出了土体结构的定量化表征参数——相对结构度,并给出了该变量在土体变形过程中的演化方程。随后基于该参数推导了结构性土的体变方程,该方程反映了结构性土在变形过程中土体结构对压缩特性的影响。最后,结合修正剑桥模型推导了三轴应力状态下结构性土的本构模型,该模型可较好地预测结构性土的力学与变形特性,通过3种天然结构性土的试验结果与模型预测对比验证了本模型的合理性。Soil structure can improve the stability of soil skeleton. Hence, the void ratio of structured soils is usually higher than that of the reconstituted soils under the same effective stress. Based on the process of the formation of structured soils, the influences of the soil structure on the deformation characteristics are analyzed. Besides, the destruction law of the soil structure in the process of deformation is investigated. A quantitative parameter of the soil structure(relative structure degree) is proposed. The evolution equation for the new parameter during the deformation is obtained according to the experimental data.The volume change equation for the structured soil is derived by incorporating the new parameter. The volume change equation describes the change of the soil structure and compression index of structured soils during deformation. The constitutive model under triaxial stress state for the structured soils is derived by incorporating the modified cam-clay model. The mechanical and deformation behaviors of the structured soils are captured by the proposed model. The new constitutive model is able to predict the mechanical behaviors of the structured soils through the comparisons between the numerical results and the experimental data from three kinds of natural structured soils.

关 键 词：结构性土 本构模型 体变方程 压缩指数 

分 类 号：TU431[建筑科学—岩土工程]