基于断裂力学能量理论的柔性纤维混凝土阻裂机理全过程分析  

The Whole Process Analysis of Crack Resistance Mechanism of Flexible Fiber Reinforced Concrete Based on Energy Theory

作　　者：秦煜[1,2] 吴华 易志坚 王威娜[1] 郑永[1] QIN Yu;WU Hua;YI Zhijiang;WANG Weina;ZHENG Yong(School of Civil Engineering,Chongqing Jiaotong University,Chongqing 400074,China;CREEC(Chongqing)Survey,Design and Research Co.Ltd,Chongqing 400023,China)

机构地区：[1]重庆交通大学土木工程学院,重庆400074 [2]中铁二院重庆勘察设计研究院有限责任公司,重庆400023

出　　处：《公路工程》2018年第4期127-132,共6页Highway Engineering

基　　金：国家自然科学基金资助项目(51408083;51508064);重庆市前沿与应用基础研究计划项目(cstc2014jcyjA30018;cstc2016jcyjA0128);交通土建工程材料国家地方联合工程实验室开放基金项目(LHSYS-2016-01)

摘　　要：为揭示柔性纤维混凝土的全过程阻裂机理,运用断裂力学能量理论,从裂纹孕育、发生、发展、临界、恶化、破坏等整个发展阶段,构建柔性纤维混凝土的全过程阻裂增强机理模型。研究表明:出现裂纹时,外力做功转化为混凝土应变能、裂纹表面能、裂纹端部塑性应变能;裂纹穿过纤维瞬间出现局部黏结破坏,脱黏部分纤维的变形能增大;裂纹穿过柔性纤维后,部分外力做功转化为脱黏功和纤维弹塑性应变能;若柔性纤维被拔断,将消耗纤维拔断能。柔性纤维对混凝土的阻裂作用,其本质是能量传递的过程。断裂力学能量理论可以揭示柔性纤维强大的耗能阻裂作用。In order to reveal the crack resistance mechanism of flexible fiber reinforced concrete,the energy theory of fracture mechanics is used to establish the model of the entire anti-cracking and enhancement.The whole process of flexible fiber preventing concrete cracking consist of crack initiation,occurrence,development,criticality,deterioration and destruction.The results show that the energy theory can reveal the important effect of flexible fiber on energy dissipation and crack resistance;When the crack occurs,the external work is transformed into the concrete strain energy,the crack surface energy and the plastic strain energy at the crack end;When the crack passes through the fiber,the local bonding failure occurs and the deformation energy of the debonding fiber increases;After the crack passing through the flexible fiber,the part of the external work is converted into debonding work and fiber elastoplastic strain energy;If the flexible fibers are pulled out,the the fracture energy of fiber is consumed.The effect of flexible fiber on the crack resistance of concrete is the process of energy transfer.The energy theory of fracture mechanics can reveal the strong energy dissipation and crack resistance of flexible fibers.

关 键 词：柔性纤维 混凝土 阻裂机理 能量理论 全过程分析 

分 类 号：TU528.572[建筑科学—建筑技术科学]