摘要
为研究地下结构混凝土随机裂缝宽度对混凝土内硫酸根离子扩散系数及浓度分布的影响,假设混凝土初始裂缝由矩形裂缝单元构成,裂缝单元出现位置的概率密度函数沿裂缝纵向服从正态分布,推导了开裂混凝土内硫酸根离子的扩散系数随裂缝宽度的变化规律.根据菲克第二定律修正硫酸根离子的扩散方程,并针对两种不同的裂缝形态参数进行了数值算例分析.结果表明:两种情况下,离子的浓度均可在50 h内达到稳定;裂缝形态参数越小且裂缝形态越不规则,离子扩散得越慢,离子浓度达到稳定的时间越长.
The influence of the stochastic crack width on sulfate diffusion coefficient and concentration in underground concrete was investigated. It is assumed that the crack is composed of crack elements, and the probability density function of crack element location along longitudinal direction of the crack follows the normal distribution. The rule of sulfate diffusion coefficient in cracking concrete varying with the cracks width was deduced. Based on Fick＇s second law,a modified diffusion equation was presented,and the numerical simulation was conducted with two crack shape parameters. The results showed that in both cases the sulfate ion concentration reached a steady state within 50 h. The small crack shape parameter and irregular crack shape slowed down the diffusion rate and the time for steady concentration.
出处
《西南交通大学学报》
EI
CSCD
北大核心
2013年第6期996-1001,共6页
Journal of Southwest Jiaotong University
基金
国家重点基础研究发展计划"973"计划资助项目(2011CB013800)
江苏省普通高校研究生科研创新计划资助项目(CXLX12_0438)
关键词
地下结构混凝土
随机裂缝宽度
扩散系数
离子浓度分布
concrete of underground structure
stochastic crack width
diffusion coefficient
ion concentration distribution
