碾压混凝土各向异性徐变损伤本构模型

碾压混凝土的徐变包括低应力水平下的近似线性徐变和高应力水平下的非线性徐变，在低应力水平下，损伤值较小，徐变近似线性，可以应用叠加原理；在高应力水平下，损伤值较大，徐变表现为明显的非线性，叠加原理不再适用，高应力水平下徐变的非线性特征可以用线性徐变和损伤耦合来描述。根据碾压混凝土材料损伤拉压显著不同的特点，分别在拉压应变空间建立了碾压混凝土的损伤演化方程，考虑粘弹性与损伤耦合，应用正交各向异性损伤理论来描述由于微裂缝扩展引起的刚度退化和应变软化，该模型能够较好地描述碾压混凝土的在复杂应力状态下的非线性徐变特性。

Anisotropic Creep-Damage Constitutive Model for Roller Compacted Concrete in Strain Space

Creep of RCC consists of approximate linear creep at the level of low stress and nonlinear creep at the level of high stress.However,at the level of low stress,the value of damage is less and overlap principle can be applied, but At the level of high stress,the value of damage is large and overlap principle cannot be adopted.Nonlinear creep of RCC may be described by coupling of linear creep and damage.Based on distinct differences of RCC on damage between tension and compression,the constitutive equation and damage evolution law are obtained in tension and compression strain space respectively.Considering the coupling of viscoelasticity and damage,the behavior of rigidity degeneration and strain softening due to microcrack propagation is described by orthotropic damage theory.The nonlinear creep of RCC under complex stress condition can be well described by the proposed model.