高强混凝土的断裂特性及其参数化分析  

Fracture characteristics and parametric analysis of high strength concrete

作　　者：龙巧 陈红鸟[1,2] 刘灯凯 沈杰 许应杰 LONG Qiao;CHEN Hongniao;LIU Dengkai;SHEN Jie;XU Yingjie(Research Center of Space Structures,Guizhou University,Guiyang 550025,Guizhou,China;Key Laboratory of Structural Engineering of Guizhou Province,Guizhou University,Guiyang 550025,Guizhou,China)

机构地区：[1]贵州大学空间结构研究中心,贵州贵阳550025 [2]贵州大学贵州省结构工程重点实验室,贵州贵阳550025

出　　处：《建筑科学与工程学报》2024年第3期34-42,共9页Journal of Architecture and Civil Engineering

基　　金：贵州省科技计划项目(黔科合基础-ZK[2022]重点007);国家自然科学基金项目(51768011)。

摘　　要：为了研究高强混凝土(HSC)的断裂特性,对单边切缝的HSC梁进行三点弯曲试验,采用扩展有限元法(XFEM)对HSC梁进行数值模拟;采用数字图像相关技术(DIC)得到不同加载阶段HSC梁的水平应变场,并采用XFEM模型分析了不同缝高比a_(0)/D、梁跨度S对HSC断裂特性的影响。结果表明:模拟的荷载-裂缝口张开位移(P-s)曲线在加载阶段与试验结果基本一致,但在卸载阶段小于试验值;模拟的临界有效裂缝长度a_(c)、起裂荷载P_(ini)、峰值荷载P_(un)、峰值荷载下的裂缝口张开位移s、起裂断裂韧度K_(IC)^(ini)、失稳断裂韧度K_(IC)^(un)与试验结果大致吻合,即二者P-s曲线和断裂参数均比较接近,数值模型能较好模拟HSC的断裂行为;在试验过程中,裂缝路径不规则,而在数值模拟过程中,裂缝基本呈直线扩展;随着缝高比a_(0)/D增大,起裂荷载P_(ini)、峰值荷载P_(max)、K_(IC)^(un)减小,K_(IC)^(ini)基本不变;随着跨度S的增大,起裂荷载P_(ini)、峰值荷载P_(max)减小,K_(IC)^(un)增大,而K_(IC)^(ini)基本保持稳定。In order to investigate the fracture characteristics of high strength concrete(HSC),three-point bending test was performed on HSC beams with centre-notched,and the extended finite element method(XFEM)was employed to simulate the beams.The horizontal strain fields of the beams in different loading stages were obtained by digital image correlation technique(DIC).In addition,an analysis of the effect of the seam height ratio a_(0)/D and the span S on the fracture characteristics was conducted with XFEM models.The results show that the simulated load-crack opening displacement(P-s)curve is basically consistent with the experimental results in the loading stage,but smaller than the experimental results in the unloading stage.The simulated critical effective crack length a c,initiation load P_(ini),peak load P_(un),crack opening displacement under peak loads,initiation fracture toughness K_(IC)^(ini) ,and instability fracture toughness K_(IC)^(un) are roughly in accordance with the experimental results.Therefore,the P-s curve and fracture parameters measured by XFEM are consistent with those obtained by the test respectively,and the XFEM models can preferably simulate the fracture behavior of HSC.During the experiment process,the crack path is irregular,while in the numerical simulation,the cracks basically extend in a straight line.As a_(0)/D increases,the initiation load P_(ini),peak load P_(max)and instability fracture toughness K_(IC)^(un) decrease,and the initiation instability toughness K_(IC)^(ini) basically unchanges.With the increase of S,the initiation load P_(ini) and peak load P_(max)decrease and the instability fracture toughness K_(IC)^(un) increase,while the initiation instability toughness K_(IC)^(ini) basically stays unchanged.

关 键 词：高强混凝土 断裂性能 数值分析 三点弯曲梁 

分 类 号：TU528[建筑科学—建筑技术科学]