大骨料混凝土在动态三轴拉压压应力状态下的强度

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发布时间：2021-11-21

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采用大型混凝土静、动态三轴液压伺服试验系统，比较了大骨料混凝土试件和湿筛二级配混
凝土试件在动态三轴拉压压应力状态下的强度特征．结果表明：2种试件的破坏均为典型的拉伸破
坏，裂缝垂直于拉应力方向；动态抗拉强度随应变率的增大而增大，随压应力的增大而减小；抗拉
强度增长系数与应变率比的对数呈线性关系；大骨料混凝土试件的动态抗拉强度及其对应变率的
敏感性均比湿筛二级配混凝土试件的要小．在八面体应力空间中建立了破坏准则，为大体积结构
的非线性分析和抗震设计提供了试验依据．
关键词：大骨料混凝土；动态三轴拉压压；强度；破坏准则
中图分类号：TV431 文献标志码：A doi：10．3969／j．issn．1007—9629．2015．05．001
Strength of Large Aggregate Concrete under Dynamic Triaxial
Compression-Com pression Tension Stress State
SON G Yupu， D UAN Xiaoliang ， SH I Linlin
(State Key Laboratory of Coastal and Offshore Engineering，Dalian University of Technology，Dalian 116024，China)
Abstract：Strengths of large aggregate concretes and the corresponding wet—screened concretes were studied
experimentally．Specimens were subj ected to dynamic triaxial compression—compression-tension stress，
using large concrete static and dynamic triaxial servo test system． Results show that failures of the two
kinds of concretes are typical tensile failures，and the cracks are perpendicular to the tensile stress direc—
tion． Their dynamic tensile strength increases with the increase of strain rate，and decreases with the in—
crease of compressive stress．The increasing coefficient of tensile strength and the logarithm of strain rate
ratio are in linear relationship． Dynamic tensile strength and its sensitivity to strain rate of large aggregate
concretes are lower than those of the wet—screened concretes．By fitting the experimental data，failure cri—
teria in octahedral stress space were established，which provides an experimental basis for nonlinear analy—
sis and seismic design of m ass concrete structure．
Key words：large aggregate concrete；dynam ic triaxial compression-compression-tension；strength；failure
criterion
大型混凝土结构，特别是水工大体积混凝土结
构，在使用过程中除了承受静态荷载的作用外，还要
承受复杂的动态荷载的作用。动态荷载对混凝土的
力学性能影响较大，如拱坝有些部位处于动态多轴
拉压应力状态，而这种状态下的混凝土抗拉强度低
于单轴抗拉强度，其抗压强度也低于单轴抗压强