论文部分内容阅读
本文采用最大尺寸为 12 0 0mm× 12 0 0mm× 2 0 0mm的楔入劈拉试件 ,利用光弹贴片法对混凝土预制缝的起裂、稳定扩展直至失稳破坏全过程进行了系统的研究 .采用照相机及数码摄像机拍摄了光弹贴片所显示的裂缝扩展全过程 ,获得了各级荷载下各试件裂缝的亚临界扩展量 .在此基础上 ,根据试验测得的起裂荷载Pini及最大荷载Pmax计算了混凝土起裂断裂韧度KiniIC 及失稳断裂韧度KunIC .结果表明 ,混凝土KiniIC 与试件高度无关 ,而当试件高度大于 6 0 0mm时 ,所测得的KunIC也与试件高度无关 ,这说明混凝土双K断裂参数 (KiniIC 及KunIC)可以作为混凝土的材料参数
In this paper, a wedge splitting test specimen with a maximum dimension of 1200 mm × 1200 mm × 200 mm was used. The optical-elastic patch method was used to systematically study the initiation and propagation of prefabricated concrete joints and the steady expansion until failure. The whole process of crack propagation showed by photoelastic patch was photographed by camera and digital video camera, and the subcritical expansion of each specimen crack under various loads was obtained.On the basis of this, Pini and the maximum load Pmax, the fracture initiation toughness KiniIC and the instability fracture toughness KunIC of concrete were calculated.The results show that the KiniIC of concrete has nothing to do with the specimen height, but when the specimen height is more than 600mm, the measured KunIC Which has nothing to do with the specimen height, which shows that the double K fracture parameters of concrete (KiniIC and KunIC) can be used as the material parameters of concrete