混凝土单轴压缩蠕变试验的模拟研究  

Simulation study on creep test of concrete in uniaxial compression

作　　者：任非 REN Fei(School of Applied Engineering,Henan University of Science and Technology,Sanmenxia 472000,China;Sanmenxia Vocational and Technical College,Sanmenxia 472000,China)

机构地区：[1]河南科技大学应用工程学院,河南三门峡472000 [2]三门峡职业技术学院,河南三门峡472000

出　　处：《混凝土》2022年第1期65-69,共5页Concrete

摘　　要：通过对混凝土试件进行数值模型重构,研究不同恒定轴向应力下混凝土轴向应变的变化、破坏模式以及微裂纹的倾角规律。主要结论为(1)轴向应力与失效时间符合幂函数关系,拟合得到混凝土的单轴压缩的长期强度为44.83 MPa,与瞬时抗压强度的比值为0.80;(2)在蠕变加载过程中,蠕变曲线大致可以分为3个阶段,即初始蠕变阶段、等速蠕变阶段和加速蠕变阶段,其中等速蠕变阶段持续时间最长;(3)在外部恒定荷载下界面过渡区首先萌生微裂纹,随后微裂纹逐渐扩展,最终贯通整个试件,发生单剪切面破坏或者"X"型共轭剪切破坏;(4)微裂纹倾角分布在两个集中范围,即40°~80°和130°~160°,许多微裂纹所组成的主破裂面是混凝土试件蠕变失稳破坏的最重要的因素。By reconstructing the numerical model of concrete specimens,the changes in the axial strain of concrete under different constant axial stresses,the failure mode and the inclination of microcracks are studied.The main conclusions are(1)Axial stress and failure time conform to a power function relationship,the long-term strength of concrete in uniaxial compression obtained by fitting is44.83 MPa,and the ratio of the instantaneous compressive strength is 0.80.(2)Under creep loading in the process,the creep curve can be roughly divided into three stages,namely the initial creep stage,the constant velocity creep stage and the accelerated creep stage,of which the constant velocity creep stage lasts the longest.(3)Under external constant load the interface transition zone first initiated microcracks,and then the microcracks gradually expanded,and finally penetrated the entire specimen,causing single-shear plane failure or“X”-shaped conjugate shear failure.(4) The micro-crack inclination angles were distributed in two concentrated ranges.That is,40° ~80° and130° ~160°,the main fracture surface composed of many micro-cracks is the most important factor for the creep instability and failure of concrete specimens.

关 键 词：混凝土 单轴压缩 蠕变 数值模拟 

分 类 号：TU528.01[建筑科学—建筑技术科学]