蠕变参数劣化的时效性及变参数蠕变模型

为了更好地研究岩石在不同条件下的蠕变特性，采用MTS812.02试验机对岩石进行三轴蠕变试验。针对岩石蠕变曲线的特征，结合流变力学理论通过引入弹塑性元件来对岩石的加速蠕变曲线进行描述，并结合模型方程和试验数据，提出一种确定蠕变参数的新方法，对确定的蠕变参数与应力和时间之间的关系进行分析，建立考虑过应力差和时间双重影响的损伤蠕变模型。结果表明：引入的损伤模型亦可以较好地反映岩石在卸载蠕变过程中的损伤程度，为蠕变模型和确定模型参数的理论研究提供一个新的思路；改进后的模型与试验数据具有良好拟合度，也证明了该确定蠕变参数方法的正确性；在考虑蠕变参数在应力和时间双重作用下的劣化性质，建立了蠕变参数劣化模型，对传统的损伤蠕变模型进行改进，得到新的蠕变模型与试验数据具有良好拟合度，说明了改进后模型正确性与合理性，也证明了确定蠕变参数方法的正确性，且得出蠕变参数具有更明确的物理意义。

Time-dependentness of Creep Parameter Degradation and Variable Parameter Creep Model

In order to better study the creep properties of rocks under different conditions, the rock triaxial creep test was carried out by using the MTS812.02 test machine. According to the characteristics of rock creep curve, the accelerated creep curve of rock was described by introducing elastic-plastic elements. A new method for determining creep parameters was proposed by combining model equations and experimental data. The relationship between the determined creep parameters and stress and time was analyzed. A damage creep model considering stress and time effects was established. The results shown that the introduced damage model could also reflect the damage degree of rock during unloading creep, and provided a new idea for the creep model and the theoretical study of determining model parameters. The improved model had good fitness with the experimental data, and it also proved the correctness of the method for determining creep parameters. Considering the degradation properties of creep parameters under the action of stress and time, the creep parameter degradation model was established, and the traditional damage creep model was improved. The new creep model had good fitting with the test data. The correctness and rationality of the improved model also proved the correctness of the method for determining creep parameters.And the creep parameters had a clearer physical meaning.