| 摘要: |
| 基于离散元程序YADE编制了流体与颗粒相互作用及粒间范德华力作用模型，从粒径比、粒间范德华力两个方面分析了泥浆侵入土层初始恒速阶段的堆积状态。结果表明，范德华力是影响泥膜形成速度和空间力链结构的重要因素，使泥浆颗粒堆积比例产生量的变化，而粒径比是决定泥膜状态的关键因素；力链结构在空间的分布和联系反映了泥浆颗粒在土层中堆积具有一定的连续性和单向性。渗流单向性是堆积单向性的一种重要表现形式，通过砂-膨润土混合物变水头渗透试验给出了验证。增大范德华力可以在土层表面更快形成泥皮，这为通过理论或试验手段提高流体介质的Hamaker常数来优化泥浆配比提供了理论支撑。 |
| 关键词: 泥膜状态 YADE 细观分析 范德华力 空间力链结构 |
| DOI： |
| 分类号:TU443 |
| 基金项目:教育部博士点基金资助项目（20133204120014）；住建部基金资助项目（2013-K3-16）；江苏高校优势学科建设工程资助项目（2013） |
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| Mesoscopic analysis of slurry membrane state for slurry invading stratum and verification of packing unidirectionality |
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LIU Cheng1, YANG Ping1, WANG Hai-bo1, PAN Xiao-ming2
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1.College of Civil Engineering，Nanjing Forestry University;2.Shenzhen Metro Group Co., Ltd.
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| Abstract: |
| A model of fluid-particles interaction and Van der Waals force is developed based on discrete element program YADE to analyse the packing state of slurry particles during the initial constant rate period. The packing state is analyzed from partical diameter ratio and Van der Waals forces. The analysis results show that the Van der Waals force has a great influence on the velocity of the slurry membrane formation and the spatial force chain structure, resulting in quantitative change of the packing ratio. The partical diameter ratio is the determinant of the slurry membrane state. The spatial distribution and connections of the force chain structure reflecting the slurry particles packing in soil have features of continuity and unidirectionality. Seepage unidirectionality is an important form of the packing unidirectionality, and it is validated by a set of sand-bentonite mixture falling head permeability tests. Larger Van der Waals force can make faster the slurry membrane formation on the soil surface, which provides a theoretical support to optimize slurry mixing ratio by raising fluid Hamaker constants through the theoretical and experimental methods. Owing to complex formation mechanism of the slurry membrane and many influence factors, it is unable to reveal formation process of the slurry membrane clearly. And a problem of the slurry membrane formation transformation from the constant-speed stage into the constant-pressure stage will be an research emphasis in the future. |
| Key words: slurry membrane state YADE mesoscopic analysis Van der Waals force spatial force chain structure |
