有压水环境中的混凝土动态抗压性能试验研究

发布时间：2018-06-05 17:28

本文选题：混凝土 + 水压力　；参考：《实验力学》2017年03期

【摘要】：对有压水环境中的混凝土进行了不同应变速率下的动态压缩试验研究,获得了水压为0~10MPa时的混凝土含水量特征以及不同应变速率下的应力应变曲线。试验结果表明:应变速率不高于10~(-3)/s时,混凝土的应力应变曲线与干燥混凝土的相似,受力状态如同单轴加载;在应变速率为10~(-2)/s时,其应力应变曲线的后半支随水压力增加而提高,与三轴受力状态类似,水压力对混凝土形成了围压效应。混凝土的强度及其动态增强因子随应变速率呈非线性增加趋势,水压力越高则增长速度越快。强度压力增强因子随水压力的变化趋势在不同应变速率下存在差异。在慢速加载时,强度压力增强因子变化幅度为10%,而快速加载时,其随水压力提高而增加,且显著高于慢速加载时的情况。在深入研究混凝土强度动态增强因子和压力增强因子的基础上,构建了有压水环境中混凝土的经验本构模型。该模型考虑了水压力和应变速率共同作用对混凝土强度的影响,与试验数据吻合较好。结合混凝土的含水量特征,进一步分析了不同应变速率下孔隙水对其力学性能影响的作用机理,分析表明含水量不同导致了粘滞应力和超孔隙水压力的差异,从而引起混凝土强度的非线性增长。
[Abstract]:The dynamic compression tests of concrete in pressurized water environment were carried out at different strain rates. The water content characteristics of concrete under water pressure of 0 ~ 10 MPA and the stress-strain curves at different strain rates were obtained. The experimental results show that the stress-strain curve of concrete is similar to that of dry concrete when the strain rate is not higher than 10 ~ (-3) / s, and the stress state is similar to that of uniaxial loading, and when the strain rate is 10 ~ (-2) / s, the stress-strain curve of concrete is similar to that of dry concrete. The latter half of the stress-strain curve increases with the increase of water pressure, which is similar to the triaxial stress state. Water pressure forms a confining pressure effect on concrete. The strength of concrete and its dynamic enhancement factor show a nonlinear increasing trend with the strain rate, the higher the water pressure, the faster the growth rate. The variation trend of strength pressure enhancement factor with water pressure is different at different strain rates. At slow loading, the change of strength pressure enhancement factor is 10%, while at fast loading, it increases with the increase of water pressure, and is significantly higher than that under slow loading. The empirical constitutive model of concrete in pressurized water environment was established on the basis of the study of dynamic strength enhancement factor and pressure enhancement factor of concrete. The influence of water pressure and strain rate on the strength of concrete is considered in this model, which is in good agreement with the experimental data. Combined with the characteristics of water content of concrete, the mechanism of the influence of pore water on mechanical properties of concrete under different strain rates is further analyzed. The analysis shows that the difference of water content leads to the difference of viscous stress and excess pore water pressure. Therefore, the nonlinear growth of concrete strength is caused.
【作者单位】：西安理工大学土木建筑工程学院;三峡大学土木与建筑学院;
【基金】：国家自然科学基金项目(51279092) 水利部公益性行业科研专项(201501034-03)资助
【分类号】：TU528

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