基于分形理论分析裂缝形态对纤维/混凝土渗透性的影响  

Investigation on effect of crack geometry on permeability of fiber/concrete based on fractal theory

作　　者：丁一宁[1] 马跃 郝晓卫 DING Yining;MA Yue;HAO Xiaowei(State Key Laboratory of Coastal and Offshore Engineering,Dalian University of Technology,Dalian 116024,China)

机构地区：[1]大连理工大学,海岸与近海工程国家重点实验室,大连116024

出　　处：《复合材料学报》2020年第11期2908-2916,共9页Acta Materiae Compositae Sinica

基　　金：国家自然科学基金(51578109)。

摘　　要：分形维数可以表征裂缝形态,能够用来分析混凝土裂缝断面的粗糙程度。裂缝形态对开裂混凝土的渗透性有重要影响,为研究这种影响,利用劈裂试验获得不同宽度的裂缝,使用不同的纤维种类,并设置多种纤维掺量,得到粗糙程度不同的裂缝断面,通过水渗透试验测量不同裂缝宽度时混凝土的渗透系数。采用激光扫描仪扫描裂缝断面并重构3D断面几何形态,采用立方体覆盖法计算断面分形维数。采用分形维数将实测裂缝宽度和有效裂缝宽度联系起来,联立达西定律和泊肃叶定律建立开裂混凝土渗透系数和分形维数的函数关系。结果表明:使用相同的网格划分法,分形维数随着纤维掺量的增加而增大;渗透系数随着纤维掺量的增加而减小;函数关系式中分形维数的指数绝对值和修正系数都随裂缝宽度增加而减小。Fractal dimension can characterize the geometric properties of cracks and can be used to analyze the rupture surface roughness of concrete.Crack geometry plays an important role in water permeability of cracked concrete.In order to investigate this effect,a series of crack widths were obtained through feedback controlled splitting test and a variety of rupture surface roughness was achieved by adjusting fiber types and fiber contents.Water permeability test was performed to measure the permeability coefficients under different crack widths.3D rupture surface was re-established after scanning the real rupture surface via laser scanning device.The fractal dimension was calculated based on the cube covering method.The function between fractal dimension and water permeability coefficient was established by correlating the measured crack width and the effective crack width and solving Darcy’s Law and Poiseuille’s Law simultaneously.The results show that fractal dimension calculated by the same meshing approach increases as the fiber content increases.Water permeability coefficient reduces with the rise of the fiber content.The results also demonstrate that both the absolute value of the exponential of fractal dimension and the correction factor in the function decreases with crack width increasing.

关 键 词：分形维数 渗透性 断面粗糙程度 开裂混凝土 纤维 

分 类 号：TU528.572[建筑科学—建筑技术科学]