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Burgers模型只能描述岩石蠕变的前两个阶段,为了描述蠕变全过程,考虑蠕变参数的时间效应及损伤带来的影响,采用非定常黏性元件取代Burgers模型中串联的定常黏性元件,使其能描述加速蠕变阶段。根据损伤变量的变化特征,假定了一个函数,经过Lemaitre应变等效原理,代入Kelvin模型可得到能描述蠕变衰减阶段的模型。试验数据拟合结果显示,改进的Burgers模型能很好地描述加速蠕变阶段,模型拟合曲线与试验曲线基本吻合,相关系数高,参数取值也在合理范围内;非定常Burgers模型更适合描述不同应力下的岩石蠕变特征曲线。
Burgers model can only describe the first two stages of rock creep. In order to describe the whole process of creep, considering the time effect of creep parameters and the influence of damage, the unsteady viscous component is used to replace the steady-state viscosity of Burgers model Components, so that it can describe the accelerated creep stage. According to the variation characteristics of damage variables, a function is assumed. After Lemaitre strain equivalence principle, the Kelvin model can be substituted into the model to describe the creep attenuation stage. The experimental data fitting results show that the improved Burgers model can well describe the accelerating creep stage. The model fitting curve is in good agreement with the experimental curve, the correlation coefficient is high and the parameter values are within a reasonable range. The unsteady Burgers model is more suitable Describe the rock creep characteristics under different stresses.