论文部分内容阅读
利用MTS810电液伺服材料试验系统及其配套的MTS652.02高温电炉,分别对泥岩进行常温与700℃下蠕变特性试验。基于函数阶微积分理论建立泥岩函数阶蠕变本构模型,通过模型阶数对比,明确应力水平和温度对泥岩蠕变特性的影响规律。根据物质组分及细观结构试验结果,解释模型阶数变化的原因,进而说明泥岩蠕变特性变化机理。结果表明:700℃下函数阶蠕变模型参数中阶数随时间变化分为3个阶段,与蠕变变形的3个阶段一一对应,相同时刻,阶数随应力水平的升高而增大,表明较高应力水平下岩石蠕变变形过程中黏性特性加强;与25℃下模型阶数变化曲线相比,700℃下曲线第2变化阶段持续时间更长,说明高温作用能有效提高泥岩稳定蠕变过程中的黏性特性;初始时刻700℃下模型阶数大于25℃下对应值,并且差值随应力增大逐渐减小,表明低应力水平下高温作用能提高泥岩瞬时蠕变过程中的黏性特性,但较高应力下高温作用的影响不明显;700℃下泥岩中产生部分伊利石,热膨胀作用使得泥岩内部细观结构较常温下更加密实,这两方面是导致应力水平与高温作用对岩石蠕变特性产生影响的根本原因。
The MTS810 electro-hydraulic servo material test system and its supporting MTS652.02 high temperature electric furnace were used to test the creep characteristics of mudstone at normal temperature and 700 ℃ respectively. Based on the theory of functional order calculus, the creep constitutive model of mudstone function is established. By comparing the model order, the influence of stress level and temperature on the creep characteristics of mudstone is clarified. According to the results of material composition and mesostructure test, the reasons for the change of model order are explained, and then the variation mechanism of creep characteristics of mudstone is explained. The results show that the order of functional order creep model parameters at 700 ℃ is divided into three stages with time, corresponding to the three stages of creep deformation. At the same time, the order increases with the increase of stress level , Which indicates that the viscous properties of rock during creep deformation under higher stress level are strengthened. Compared with the model order curve at 25 ℃, the second change stage of the curve at 700 ℃ lasts longer, which shows that the high temperature effect can effectively improve the mudstone The viscous characteristics of the stable creep process were also studied. The model order at 700 ° C was greater than the corresponding value at 25 ° C, and the difference gradually decreased with increasing stress, indicating that high temperature at low stress level can improve the transient creep process of mudstone However, the effect of high temperature is not obvious under high stress. Part of illite is produced in mudstone at 700 ℃. The thermal expansion makes the internal structure of mudstone denser than normal temperature. The Root Cause of High Temperature Effect on Rock Creep Property.