三点弯曲梁法研究砼双K断裂参数及其尺寸效应  

Double-K Fracture Parameter of Concrete and Its Size Effect by Using Three point Bending Beam Method

作　　者：吴智敏[1] 徐世烺[1] 王金来[1] 刘毅[1] 

机构地区：[1]大连理工大学海岸及近海工程国家重点实验室,大连116024

出　　处：《水力发电学报》2000年第4期16-24,共9页Journal of Hydroelectric Engineering

基　　金：国家杰出青年科学基金;辽宁省自然科学基金

摘　　要：本文采用三点弯曲梁试件利用在试验中测得的最大荷载 Pm ax及对应的裂缝口张开位移CMODc等参数 ,根据虚拟裂缝模型求得了砼裂缝亚临界扩展量 Δac、起裂断裂韧度 KiniIC、失稳断裂韧度 KunIC(即双 K断裂参数 )及临界裂缝尖端张开位移 CTODc。结果表明 ,砼双 K断裂参数及 CTODc均与试件尺寸无关 ,可以作为描述砼结构裂缝的起裂、稳定扩展及失稳断裂全过程的材料常数 ,而且试验方法简单 ,无需加卸载过程且在普通实验室即可实现。Using three point bending beams of concrete and the maximum load P max and the corresponding crack mouth opening displacement CMOD c measured in experiments, the precritical crack propagation length Δa c , initiation fracture toughness K ini IC , unstable fracture toughness K un IC (double K fracture parameter) and the critical crack tip opening displacement CTOD c were analytically determined based on the fictitious crack model. The results show that the double K fracture parameter and CTOD c are size independent. Therefore, the double K fracture parameter can be considered as a fracture parameter for concrete material to describe the cracking initiation, stable growth, and unstable propagation process for concrete structures. The testing method for the determination of K ini IC and K un IC is quite simple without unloading and reloading procedures and can be realized in a normal laboratory.

关 键 词：双K断裂参数 混凝土 尺寸效应 三点弯曲梁法 

分 类 号：TU370.2[建筑科学—结构工程] TV331[水利工程—水工结构工程]