摘要
采用大连理工大学的混凝土大型静、动三轴试验系统,对经受200℃―600℃高温后的C30普通混凝土试件进行了等比例三轴压试验。观察了各温度后试件的破坏形态,测得了三轴强度、峰值应力点处的应变及应力-应变曲线。试验表明,高温后三轴强度和峰值应力点的应变较单轴状态有较大的增长,中间主应力对多轴强度及峰值应力点处应变的影响较为显著。随着温度的升高,三轴抗压强度的降低程度与单轴下不同,八面体应力空间正应力、剪应力破坏强度与单轴抗压强度的相对值在200℃后加速增大。分析了温度和应力比对破坏强度的影响,在八面体应力空间建立了破坏强度与应力比、温度的关系式,可以为复杂应力状态下高温后混凝土的力学分析提供试验和理论基础。
Triaxial equal proportionable compressive tests on C30 normal concrete samples subjected to 200℃- 600℃ were performed, using a large-scale dynamic-static triaxial concrete test system at the State Key Laboratory of Coastal and Offshore Engineering. The failure modes of samples are observed, and the triaxial strength, strains at peak stress, and stress-strain curves are recorded. Test results show that, triaxial compressive strength is greatly larger than uniaxial strength for the same designated temperature, and middle stress has significant influence on both tri-axial compressive strengths and strains at peak stress. In addition, with the increase of suffered temperature, the drop rates of tri-axial compressive strength are different from those of uniaxial compressive strength. Relative to uniaxial compressive strength, the increase in both normal stress strength and shear stress strength in octahedral stress space becomes more significant with the further increment of suffered temperature after 200℃. The influence of stress ratio and temperature on triaxial compressive strength is analyzed, and a regression equation describing relationship among triaxial compressive strength, stress ratio, and temperature is proposed in octahedral stress space, which can provide experimental and theoretical foundation for mechanical analysis of concrete structure suffered from high temperature under complex stress condition.
出处
《工程力学》
EI
CSCD
北大核心
2009年第10期159-164,170,共7页
Engineering Mechanics
基金
辽宁省教委基金项目(2023901023)
关键词
高温
混凝土
三轴压
应力比
八面体应力空间
high temperature
concrete
triaxial compression
stress ratio
octahedral stress space
