中文摘要：

混凝土材料在不同应力路径下或复杂加载条件下会表现出差异性显著的应力应变关系,在小幅循环加载条件下,其应力应变关系会表现出类似于弹性变形的滞回曲线.在不同应力水平下,混凝土的应力应变关系以及破坏特性都具有静水压力相关特点,即随着静水压力增大,各向异性强度特性弱化.此外,混凝土受压及受拉破坏机理不同,因而对应于混凝土硬化损伤亦有不同,即可分为受压硬化损伤,受拉硬化损伤及两者的混合硬化损伤类型.基于Hsieh模型,对该模型进行了三点改进.（1）针对小幅循环加载下混凝土无塑性变形的试验规律,而模型中在应力水平较低的循环加载条件下始终存在塑性变形的预测问题,采用在边界面模型框架下,设置了应力空间的弹性域,初始屈服面与后续临界状态屈服面几何相似的假定.（2）基于广义非线性强度准则将原模型采用变换应力方法将其推广为三维弹塑性本构模型,采用变换后模型可合理的考虑不同应力路径对于子午面以及偏平面上静水压力效应形成的影响,并避免了边界面应力点奇异问题.（3）分别对拉压两种加载损伤模式建议了相应的硬化参数表达式,可分别用于描述上述加载中产生的应变软化及强度退化行为.基于多种加载路径模拟表明：所建立的三维弹塑性本构模型可合理地用于描述混凝土的一般应力应变关系特性.

英文摘要：

A prominent variety of stress-strain relationships are displayed for concrete under different stress paths or complex loading conditions. A stress-strain relationship similar to the elastic deformation of the hysteresis loops is observed under a small amplitude of deviatoric stress. The stress-strain relationship and failure behavior are associated with the value of hydrostatic pressure under different stress paths. The prominent of anisotropic behavior is weakening with increasing the value of hydrostatic pressure. In addition, the failure mechanisms and the corresponding hardening damage processes of compression and tension, are all different. There are three hardening damage types, namely the compressive hardening damage, tensile hardening damage and the mixing hardening damage. A new model is proposed by revising Hsieh model at three aspects：（1） There is not plastic deformation for small amplitude of deviatoric stress under cyclic loading conditions, while there is always plastic deformation predicted by Hsieh model. The frame of bounding surface model is adopted and a pure elastic zone is established in the bounding surface. The assumption that the initial yield surface and subsequent critical yield surface is similar in geometry is adopted.（2） A generalized constitutive model is proposed by transformed stress method based on generalized nonlinear strength criterion. The hydrostatic pressure effect of meridian plane and deviatoric plane for different stress paths can be reasonably considered by adopting the proposed model. A problem of singular stress point on boundary surface is avoided by adopting the TS method.（3）Hardening parameter expressions based on two kinds of load in tension and compression damage pattern are proposed and can be respectively adopted to describe the strain softening and strength degradation behavior generated by loading process. The proposed model can be used to describe the general stress-strain relationship of concrete based on a variety of loading tests simulation.