【摘要】 为了研究温度对混凝土结构蠕变特性的影响,开展不同温度作用下混凝土三轴蠕变试验,分析了不同温度作用下混凝土结构的轴向蠕变特性。在温度作用下,混凝土的内部损伤与非均匀程度参数有关,建立非均匀程度参数与温度之间的关系;假定混凝土蠕变模型是关于温度和时间的函数,结合上述损伤变量和微元体强度分布概率模型,建立了考虑温度和时间双重影响的混凝土蠕变模型。基于最小二乘法和试验数据对模型的准确性进行验证,并采用西原模型对其优越性作进一步验证。结果表明:不同温度作用下蠕变损伤模型与试验数据的吻合度都较好,且相关性系数在0.95以上,说明了所建立模型的正确性;同时,该模型与试验数据的吻合度要优于西原模型,并且在描述加速蠕变方面具有一定的优越性。该理论模型为地下工程中混凝土支护结构的长期变形预测研究提供理论依据。更多还原

【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.更多还原