【摘要】 按照对土的力学行为影响的程度,将土的基本特性分为三类:基本特性、亚基本特性与关联基本特性。基本特性包括三种:压硬性、剪胀性与摩擦性,它们是土区别于其他材料的最根本特性。亚基本特性包括应力历史依存性、应力路径依存性、软化特性、各向异性、结构性、蠕变特性、颗粒破碎特性以及温度特性等等,它们通过影响三种基本特性的发展演化规律而间接影响土的应力应变关系。关联基本特性包括屈服特性、正交流动性、相关联性、共轴特性以及临界状态特性等等,它们是考虑建立土的弹塑性本构模型过程中需要关注的基本概念或基本假定。在详细论述土的基本特性及其相互关系后,又通过对非线性弹性的Duncan-Chang模型、弹塑性的Cam-clay模型及其系列UH模型、Asaoka模型、Li-Dafalias模型、Yin-Graham EVP模型以及大陆学者的诸多模型进行深入剖析,具体阐述怎样对土的基本特性进行抽象概括建立本构模型、各本构模型能分别反映哪些特性以及是通过怎样的途径实现对土的基本特性的反映。随后,又探讨了将本构模型应用于数值模拟中的诸多思考以及土工计算方面的个人体会。分别讨论了土工数值模拟的精度以及影响因素,数值模拟中本构模型的选取及参数的获得,变形计算分析中土体初始状态的考虑方法,土体破坏过程模拟分析中对应变局部化的处理,以及在土与结构的接触特性分析中解决二者位移不连续问题的建议。更多还原

【Abstract】 According to the degree of influence on stress-strain relationship,soil behaviors can be categorized as essential behaviors,expressional behaviors and relative behaviors.The essential behaviors including compressive hardening,dilatancy and friction are those fundamental characteristics differing soils from other continuous materials.The expressional behaviors include such as stress history dependence,stress path dependence,softening,anisotropy,structure,creep,particle crushing,and temperature effect.They indirectly influence the stress-strain relationship of soils through affecting the essential behaviors of soils.The relative behaviors consist of such as yielding,normality flow,associated flow,coaxiality,and critical state.They are basic concepts or assumptions to be incorporated into an elasto-plastic constitutive model if such model is desired.Following a detailed discussion on the soil behaviors and their mutual relations,a comprehensive review is provided on a few representative constitutive models,e.g.,the Duncan-Chang nonlinear elastic model,the Cam-clay elastio-plastic model and the UH model,the Asaoka model,the Li-Dafalias model,the Yin-Graham EVP model and other constitutive models developed by Chinese researchers.The focus is placed mainly on how to conceptualize the intrinsic soil behaviors and lead to constitutive models,and which behaviors can be reflected by each constitutive model and how.Afterwards some considerations and personal experiences are shared on implementing constitutive models into numerical simulation.The discussion focuses on the accuracy of numerical simulation and the influencing factors,selection of proper constitutive models and parameters,consideration of spatial variation of soil modulus in deformation calculation,the strain localization and some solutions for fixing the problems caused by displacement discontinuity at soil-structure contacts in numerical simulation.更多还原