混凝土单轴加载动力性能试验研究

为了探究混凝土单轴加载动力性能,设置了三种不同强度等级的混凝土和四种加载应变率,用液压伺服试验机和材料直剪仪对混凝土开展单轴受压、单轴劈拉和剪切进行试验研究,得到了不同加载工况下混凝土的破坏形态和强度特征值,并分析了加载应变率对混凝土受压、劈拉和剪切力学性能的影响。结果表明,加载应变率对混凝土受压、劈拉和剪切加载方式均具有明显影响;随着加载应变率的提高,混凝土剪切破坏形态由静力加载应变率剪切破坏断面不平整和平行于剪切方向裂缝较为不规整,发展至动力加载应变率混凝土剪切破坏断面较为平整和平行于剪切方向破坏裂缝逐步平直;混凝土剪切强度随着加载应变率的提高逐步增大,受加载应变率影响剪切强度提高幅度低于劈拉加载方式,高于受压加载方式;同时,从定量和破坏机理角度分析了加载应变率对混凝土力学性能影响。

Experimental Study on Dynamic Behavior of Concrete under Uniaxial Loading

In order to study the dynamic performance of concrete under uniaxial loading,three kinds of concrete with different strength grades and four kinds of loading strain rates are set up.The hydraulic servo machine and material direct shear apparatus are used to carry out uniaxial compression,uniaxial splitting tension and shear tests on concrete.The failure modes and strength characteristic values of concrete under different loading conditions are obtained from the tests,and the effects of loading strain rates on compression,splitting tension and shear of concrete are analyzed.The main conclusions are as follows: the compression,splitting and shear loading modes of concrete are obviously affected by the loading strain rate;with the increase of the loading strain rate,the shear failure mode of concrete develops from the irregularity of the static loading strain rate,the irregularity of the shear failure section and the irregularity of the cracks parallel to the shear direction to the dynamic loading strain rate.The shear failure section of concrete is fairly flat and the cracks parallel to the shear direction are gradually straight;the shear strength of concrete increases with the increase of loading strain rate,and the increase of shear strength affected by loading strain rate is lower than that of splitting tension loading mode and higher than that of compression loading mode;in addition,the influence of loading strain rate on the mechanical properties of concrete is analyzed quantitatively and from the point of view of failure mechanism.