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将Burgers模型与粘塑性模型串联,得到能描述沥青砂3个蠕变阶段的粘弹塑本构模型。开展了40℃,不同应力水平下沥青砂单轴蠕变实验,通过非线性拟合确定了模型中材料参数。利用模型预测了沥青砂蠕变变形和应变率变化,并与实验结果和Burgers模型预测结果进行了比较。结果表明,该模型不仅能描述沥青砂蠕变过程的前2个阶段变形,而且能反映第3阶段的加速蠕变特征,且预测结果与实验相当吻合。
The Burgers model and the viscoplastic model are connected in series to get the viscoelastic plastic constitutive model that can describe the three creep stages of tar sands. Uniaxial creep experiments of tar sands at 40 ℃ and different stress levels were carried out. The material parameters of the model were determined by nonlinear fitting. The model was used to predict creep deformation and strain rate change of tar sands, and compared with the experimental results and Burgers model predictions. The results show that this model can not only describe the deformation of the first two stages of asphaltic sand creep process, but also reflect the accelerating creep characteristics of the third stage, and the prediction results are in good agreement with the experiments.