混凝土拱形试件双K断裂参数试验研究

Experimental Study of Double-K Fracture Parameters Using Arch Specimensin Concrete

通过混凝土拱形三点弯曲梁断裂试验,根据实测断裂全过程曲线研究了双K断裂参数,并分析了不同缝高比对双K断裂参数的影响;基于数字图像相关(DIC)方法,获得了裂缝扩展方向的全场变形信息,进一步研究了裂缝扩展的损伤断裂演化过程。结果表明,Pini/Pmax值在0.60~0.85之间;初始缝高比对双K断裂参数影响较小,双K断裂参数可描述拱形试件的断裂特性;与峰值荷载前荷载阶段相比,峰值荷载后裂缝扩展速度显著提高。

Through the arch three-point bending beam experiment of concrete, double-K fracture parameters were calculated by the experimental curve,then the influence of different seam height ratios on double-K fracture parameters was studied. Based on the digital image correlation（DIC） method,the field strain information of the crack propagation direction of concrete was obtained,and the process of fracture propagation was studied. The results show that Pini/Pmaxvalue was between 0. 60 and 0. 85. The double-K fracture parameters were not related to the initial seam-height ratio of the specimen,and they could describe the fracture characteristics of arch specimens. Compared with the preload phase of peak load,the crack propagation speed increased significantly after the peak load.