| 摘要: |
| 【目的】研究裂缝对渗流场影响的数值模拟方法，为岩石、混凝土等材料裂缝渗流场的变化研究提供支持。【方法】在等效连续介质模型框架下提出渗透系数张量修正法，并基于流量等效原理推导出修正单元的渗透系数张量矩阵。应用有限元分析软件，分别建立裂缝位于构件边界和构件内部时的分析模型，应用渗透系数张量修正法得到的渗透系数张量表达式定义裂缝单元的渗透特性，将模拟所得渗流场与裂缝真实存在的数值分析结果进行比较，并通过改变修正单元的尺寸分析渗透系数张量修正法对单元尺寸的依赖性。【结果】修正单元为10倍裂缝宽度时，与精确解相比，各分析模型所得渗流量及相应断面孔隙水压的误差均小于0.5%。就单元尺寸依赖性而言，为满足工程精度要求，从渗流量角度分析，修正单元的尺寸应不大于600倍裂缝宽度；从孔隙水压角度分析，修正单元的尺寸应不大于200倍裂缝宽度。【结论】所建立的等效处理方法合理可行，当修正单元的尺寸不大于200倍裂缝宽度时，无论是渗流量还是孔隙水压，该处理方法均能满足工程精度要求。 |
| 关键词: 裂缝 渗流场 数值模拟 渗透系数张量修正法 单元尺寸 |
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| 基金项目:国家自然科学基金项目（51379178，50779057）；中央高校基本科研业务费专项（ZD2012015） |
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| Numerical simulation method for effect of cracks on seepage field |
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GAO Xiao,LI Zong-li,LI Yang
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| Abstract: |
| 【Objective】This study focused on numerical simulation method for the impact of cracks on seepage field to support the research of variations in seepage field of rock or concrete caused by cracks.【Method】Based on the equivalent continuum model and equivalent flow principle, modified permeability tensor method was proposed and the permeability tensor matrix of the modified element was derived.Then,using finite element software,numerical model with a boundary crack or an inner crack was built.The seepage fields of established model were compared to models with real cracks and element size was modified to analyze the effect of element size on this method.【Result】Compared with the exact solution,the error of the seepage flux and the corresponding pore water pressure of the models with modified elements of 10 times of the crack width was less than 0.5%.To meet the precision requirement in engineering,from the view of seepage flux,fixed element size should be no more than 600 times of the crack width.From the view of pore water pressure,fixed element size should be no more than 200 times of the crack width.【Conclusion】The proposed method was reasonable and feasible.Considering both seepage flux and pore water pressure,the proposed method can meet the engineering precision requirements when modified element size was no more than 200 times of the crack width. |
| Key words: cracks seepage field numerical simulation modified permeability tensor method element size |
