基于力学参数时效性的非定常蠕变模型

Unsteady creep model based on timeliness of mechanical parameters

为了研究阜新恒大煤矿开采过程中围岩呈现出明显的流变性质,采用MTS815.02试验机开展不同围压作用下的蠕变试验.考虑时间与应力对蠕变参数和力学参数的影响,通过引入过应力差和时间乘积的概念,构建考虑时效性和应力状态的损伤模型,进而在西原体模型的基础上建立一个新型的非定常蠕变模型,结合砂岩不同围压作用下的蠕变试验结果,对模型中的参数进行反演,将得到的参数代入模型中与试验曲线进行对比.结果表明:蠕变试验曲线与模型曲线具有较高的拟合度,说明该模型不仅克服了传统西原体难以描述加速蠕变特性的缺点,也验证了建立的非定常非线性蠕变模型的正确性与合理性.

In order to study the obvious rheological properties of the surrounding rock during the mining process of Fuxin Hengda coal mine,the creep test under different confining pressures was carried out by using the MTS815.02 test machine.Considering the influence of time and stress on creep parameters and mechanical parameters,a damage model considering time-dependent and stress states was established by introducing the concept of over-stress difference and time product.Based on the Nishihara model,a new unsteady creep model was established.Combined with the experimental results of creep under different confining pressures of sandstone,the parameters in the model were inverted.The parameters obtained were substituted into the model for comparison with the test curves.The results show that the creep test curves has a high degree of fit with the model curves.It is shown that the model not only overcomes the shortcomings of the traditional Nishihara model which is difficult to describe the accelerated creep characteristics,but also the correctness and rationality of the established unsteady nonlinear creep model are verified.