考虑温度和围压耦合作用下岩石蠕变模型的建立

Establishment of rock creep model considering the coupling of temperature and confining pressure

为研究砂岩在温度和围压耦合条件下的蠕变特性,采用MTS815.02试验机对砂岩进行三轴蠕变试验。以损伤的角度出发,假设砂岩在加载蠕变变形过程中的蠕变性质和力学性质产生劣化,将蠕变参数定义为与时间和应力有关的函数,进而建立考虑蠕变参数劣化的蠕变本构模型。结果表明:考虑温度的蠕变模型与不同温度作用下的试验数据具有良好吻合度,且相关系数均在0.90以上,这说明该文所建立的考虑温度的蠕变模型是合适的、可行的,该模型对于不同温度作用下砂岩的蠕变特性具有较好的描述,尤其是对加速蠕变的描述,故可以采用该模型作为后续数值计算的二次开发模型。

In order to study the creep characteristics of sandstone under the coupled conditions of temperature and confining pressure,a triaxial creep test was carried out on the sandstone by using MTS815.02 testing machine.From the perspective of damage,it is assumed that the creep properties and mechanical properties of sandstone are deteriorated during the loading creep deformation process.The creep parameters are defined as functions related to time and stress,and a creep constitutive model considering the degradation of creep parameters is established.The results show that the creep model considering temperature is in good agreement with the experimental data under different temperatures.And the correlation coefficients are all above 0.90.This shows that the creep model considering temperature established in this paper is suitable and feasible.It has a good description of the creep characteristics of sandstone under different temperatures,especially the description of accelerated creep.Therefore,this model can be used as a secondary development model for subsequent numerical calculations.