关键词: 温度　三轴蠕变　损伤理论　强度分布概率　双重影响

Abstract: In order to study the influence of temperature on the creep characteristics of concrete structures,the triaxial creep tests of concrete under different temperatures were carried out,and the axial creep characteristics of concrete structures under different temperatures were analyzed. Under the action of temperature,the internal damage of concrete is related to the non-uniformity parameter,and the relationship between the non-uniformity parameter and temperature is established. It is assumed that the concrete creep model is a function of temperature and time. Combined with the above damage variables and the probability model of micro-element strength distribution,a concrete creep model considering the dual effects of temperature and time is established. Based on the least square method and experimental data,the accuracy of the model is verified,and the superiority of the Nishihara model is further verified. The results show that the creep damage model curves under different temperatures are in good agreement with the experimental data,and the correlation coefficient is above 0. 95,which shows the correctness of the established model. At the same time,the agreement between the model and the experimental data is better than that of the Nishihara model,and it has certain advantages in describing accelerated creep. The theoretical model provides a theoretical basis for the long-term deformation prediction of concrete supporting structure in underground engineering.

Key words: temperature,triaxial creep,damage theory,strength distribution probability,dual effects