The analysis of the mechanical properties and the failure mechanism of shale with the effect of temperature are of great significance to the shale gas exploitation. In this paper, triaxial creep mechanical tests and AE monitoring method for shale under step loading were carried out at different temperatures and confining pressures. The classic Poynting-Thomson creep model was improved and the modified creep model considering temperature and viscoelastic-plastic deformation were built. The test results showed that the strength of the shale was related to the confining pressures and temperatures. The creep mechanism of shale was analyzed by the acoustic emission parameters. The peak frequency of acoustic emission signals reflected the difference of the rock fracture mode. The Poynting-Thomson model was modified on the theory of nonlinear rheology, which is more suitable for creep deformation of shale. The correlation coefficient of the modified model was higher than that of the classical model. The modified model considering temperature fit the shale creep curve well and could explain the creep characteristics under the influence of temperature and stress. The new model can be widely used in the research of shale creep deformation, such as the deep exploitation of shale gas, wellbore stability and other aspects of engineering problem of shale.

分析温度对页岩力学性质和破坏机理的影响对页岩气开发具有重要意义。本文在不同温度和围压条件下，开展了阶梯加载页岩的三轴蠕变力学试验和声发射监测方法。改进了经典的Poynting-Thomson蠕变模型，建立了考虑温度和粘弹塑性变形的修正蠕变模型。试验结果表明，页岩的强度与围压和温度有关。利用声发射参数分析了页岩的蠕变机理。声发射信号的峰值频率反映了岩石破裂模式的差异。Poynting-Thomson模型在非线性流变学理论基础上进行了修正，更适用于页岩的蠕变变形。修正模型的相关系数高于经典模型。考虑温度的修正模型很好地拟合了页岩蠕变曲线，能够解释温度和应力影响下的蠕变特性。新模型可广泛应用于页岩蠕变变形研究，如页岩气深度开采、井筒稳定性等页岩工程问题。