王乾峰　刘云贺　彭刚　邹三兵

摘要：

研究了水压力环境中混凝土在经历循环荷载后的动态压缩强度，分析了水压力和循环次数对混凝土强度的影响。试验应变速率为10-5/s、10-4/s、10-3/s和10-2/s，水压为0～10 MPa。试验结果表明，在不同水压力下饱和混凝土的强度都随应变速率提高而增加，也随水压力提高呈增加地趋势。在相同水压力下，应变速率越高，混凝土强度提高越显著。饱和混凝土经过循环荷载后，其强度随荷载循环次数的增加呈现出先提高后降低的现象。应变速率越高，混凝土强度最大时所对应的荷载循环次数也相应增加。还构建了饱和混凝土强度与应变速率、水压力的关系，其与试验数据吻合较好。进一步引入了管道孔隙模型，并基于汞压法的原理和孔隙分布特点，考虑混凝土孔隙的微观结构解释了孔隙水对混凝土强度的作用机理。

关键词：

混凝土；水压力；循环荷载；应变速率；动态性能；孔隙结构

中图分类号：TU528.1

文献标志码：A文章编号：16744764（2017）02013208

Abstract：

The dynamic compression strength of concrete which undergone cyclic loading and subjected to water pressure was carried out， and effect of water pressure and cyclic times on strength of concrete was analyzed. Strain rates of tests were 10-5/s， 10-4/s， 10-3/s and 10-2/s， and water pressure ranged from 0 to 10 MPa. The results showed that strength of saturated concrete under different water pressure increased with the increasing strain rate， and that also increased with the increasing water pressure. Under the same water pressure， the concrete strength increased more significantly when the strain rate was higher. After cyclic loading， strength of saturated concrete showed the phenomenon of the first increase and then decreased as the number of load cycles increased. The higher the strain rate， the greater number of load cycles with maximum concrete strength. The relationships between concrete strength and strain rate， water pressure were established， which was in good agreement with the experimental data. Furthermore， the pipe pore model was introduced， and the mechanism of pore water on the concrete strength was explained and based on the principle of mercury intrusion porosimetry and pore distribution.

Keywords：

concrete； water pressure； cyclic loads； strain rate； dynamic property； pore structure

混凝土是大坝、港口和桥墩等结构中普遍使用的材料，这些结构经常处于水环境中，在结构表层部分会形成与水压力相等的孔隙水压力。而且，这些结构不仅承受静态荷载的作用，还要遭受地震或是动水压力的冲击。因此，有必要对水环境中的混凝土材料开展动态荷载作用下的试验研究。

许多学者考虑到结构深部承受不可忽略的水压力，开展水环境作用或孔隙水压力作用对混凝土强度影响的研究。李宗利等[1]考虑到高压水渗透和孔隙水压力对混凝土的影响，采用高水压力饱和混凝土，结果表明混凝土的抗壓强度、劈裂抗拉强度和弹性模量都随孔隙水压力的增加逐渐降低。……