浅变质板岩非定常开尔文模型研究

Study on Non-stationary Kelvin Model of Low-grade Metamorphic Slate

随着岩石蠕变特性在不同含水状态下试验研究的逐步开展,为了实际工程所需,应先提出能合理描述其蠕变规律的本构模型。为了准确描述浅变质板岩的蠕变行为,首先提出了一个新的非定常粘滞体元件,该元件的黏滞系数随时间不断发生变化。然后将该元件替换常规Kelvin模型中的定常粘滞体元件,建立了一种新的非定常Kelvin模型,并推导了模型的蠕变方程。最后基于浅变质板岩试样单轴压缩蠕变试验结果,采用曲线拟合的方法反演了非定常Kelvin模型和常规Kelvin模型的蠕变参数。通过对比试验曲线与拟合曲线发现:在不同应力水平下,相对于常规Kelvin模型,非定常Kelvin模型拟合曲线与试验结果更加吻合,说明该模型能够更好的描述浅变质板岩的蠕变特性,具有更好的适应性。

With the creep characteristics of rock gradually developing under different water conditions,the constitutive model should be reasonably established firstly for the needs of actual engineering. To describe the creep behaviour of low-grade metamorphic slate more accurately,a new non-stationary viscous component was proposed firstly. The viscosity coefficient of this component varies with time. Then a new non-stationary Kelvin model was established by replacing the stationary viscous component in the conventional Kelvin model with the non-stationary viscous component,and the creep equation of which was deduced. Based on the uniaxial compression creep test data of the low-grade metamorphic slate,the creep parameters of the conventional Kelvin model and the non-stationary Kelvin model were inversed using the curve fitting method. The comparison between test data and fitting curves shows that the fitting curves from the non-stationary Kelvin model are in better agreement with test data than that from the conventional Kelvin model under different stress levels. This indicates that the creep property of the low-grade metamorphic slate can be better described by the non-stationary Kelvin model.