针对沥青砂的非线性材料特性,结合连续损伤力学理论,对传统Burgers模型进行改造,提出了粘弹塑蠕变损伤本构模型,通过对不同实验条件下沥青砂单轴蠕变试验结果的非线性拟合,获得模型参数,然后利用模型进行预测分析,得到了不同应力水平与环境温度下的蠕变曲线和损伤演化曲线,通过比较发现该文模型能够更合理地反映沥青砂加速蠕变的非线性特征,而且蠕变过程中损伤演化的速度受蠕变时间、应力水平与环境温度的影响很大。
Considering the nonlinear characteristics of asphalt mastic and coupling continuum damage mechanics,this paper proposed a visco-elastoplastic damage constitutive model of asphalt mastic by modifying Burgers model.Based on a series of uniaxial compression creep tests which were performed under different stress levels and temperatures,a nonlinear fitting program was developed for determining model parameters.The proposed visco-elastoplastic model was used for analysis and prediction.The curves of predicted creep strain versus damage evolutional rate under different stresses and temperatures were plotted.It is shown the proposed model can be used to predict the accelerated creep behavior of asphalt mastic.In addition,the damage evolutional rate is found to be influenced distinctly by creep time,stress level and condition temperature.