沥青混合料永久变形的弹黏塑-损伤力学模型

Viscoelastoplastic-damage mechanics model of permanent deformation in asphalt mixture

对Burgers模型中串联黏壶进行了改进,并将改进模型看成是由三单元Van Der Poel模型与黏塑性元件串联组成.综合运用黏塑性力学和损伤力学理论,同时引入应变硬化变量和损伤软化变量,建立了基于应变硬化理论的沥青混合料损伤蠕变模型.再采用半正矢波间歇荷载模拟实际路面轮载作用,推导了重复荷载作用下沥青混合料永久变形的弹黏塑性损伤力学模型.根据室内重复荷载永久变形试验结果,运用最小二乘法原理,得到了弹黏塑性损伤力学模型的相关参数,并对该模型进行了验证.验证结果表明,该模型可以全面、统一地描述沥青混合料永久变形的三阶段特性.

The series-wound dashpot of Burgers model was modified and the model was considered as a combination of viscoelastic-plastic dashpot and Van Der Poel model. Coupled with the viscoelastic mechanics theory and damage mechanics theory, a new damage-creep model is established for asphalt mixture by introducing a strain hardening variable and a damage softening variable. A loading cycle consisting of a haversine load followed by a rest period was adopted to simulate the actual vehicle loading on asphalt pavement, and a viscoelastic-damage mechanics model was deduced for permanent deformation of asphalt mixture under repeated load. Subsequently, the proposed model was validated by the results of uniaxial permanent deformation tests of several asphalt mixtures, and the model parameters were obtained by the principle of least square. It is indicated that the proposed model can describe the whole three-phase permanent deformation of asphalt mixture comprehensively.