王浩然,王永志,王海,等. 砂雨模型制备PFC3D的数值模拟[J]. 水利水运工程学报,2021(4):68-74. doi: 10.12170/20200909002
引用本文: 王浩然,王永志,王海,等. 砂雨模型制备PFC3D的数值模拟[J]. 水利水运工程学报,2021(4):68-74. doi: 10.12170/20200909002
(WANG Haoran, WANG Yongzhi, WANG Hai, et al. Numerical simulation of PFC3D-based model for sample reconstitution using sand pluviation[J]. Hydro-Science and Engineering, 2021(4): 68-74. (in Chinese)). doi: 10.12170/20200909002
Citation: (WANG Haoran, WANG Yongzhi, WANG Hai, et al. Numerical simulation of PFC3D-based model for sample reconstitution using sand pluviation[J]. Hydro-Science and Engineering, 2021(4): 68-74. (in Chinese)). doi: 10.12170/20200909002

砂雨模型制备PFC3D的数值模拟

Numerical simulation of PFC3D-based model for sample reconstitution using sand pluviation

  • 摘要: 伴随土工离心试验的应用拓展与量化需求的提升,试验模型孔隙率、均匀性的精确控制与影响因素,成为目前土工离心试验技术发展的重要课题。砂雨法作为土工离心试验常用制模方法,因其制备过程与天然粗粒土地基形成过程相似、颗粒不易破碎、制样密实度范围较宽等特点被广泛应用。为认识砂雨法制备模型孔隙率的控制因素与影响规律,基于PFC3D离散元分析软件,建立了砂雨法成型过程数值模拟方法,通过探讨落距、筛孔粒径比、环境介质等因素影响规律及与已有认识进行对比,论证了数值模拟分析方法的可行性。结果表明:制备模型孔隙率与落距呈负相关性,孔隙率随落距增大而减小且趋势逐渐变缓;孔隙率与筛孔粒径比呈正相关性,孔隙率随筛孔粒径比增大而增大;孔隙率与环境介质密度呈负相关性且影响显著,模型表面水层对孔隙率起主导控制作用。

     

    Abstract: With the increasing application of geotechnical centrifuge model tests and the increasing demand of quantitative analysis, influencing factor and precise control of sample preparation on porosity and void distribution have arisen as a key issue in the development of geotechnical centrifuge modeling techniques. Sand pluviation is an important technique for preparing sand models and widely employed in geotechnical centrifuge modeling, due to the process of its reconstitution similar to the formation of natural coarse sand strata and the advantages of avoiding soil grain crushing and achieving a wide range of relative density. In order to understand the effect of control factors on the porosity of samples prepared by sand pluviation, a discrete element method based on PFC3D is established to simulate the process of sample reconstitution using sand pluviaiton. Through discrete element simulation of the effect of drop height, mesh-grain size ratio, environmental medium, the feasibility of the proposed discrete element method is properly validated with the general knowledge from physical model tests. The results show that the porosity and the drop height appear in an obvious negative correlation, and the rate of decreasing in the porosity gradually attenuates with the increase of drop height. Meanwhile, a positive correlation exists between the mesh-grain size ratio and the porosity, and the latter is found to distinctly increase with the increasing of the former. The density of environmental medium is exhibited in a significant negative correlation with the porosity and has an important influence. Consequently, the layer thickness of model surface water plays a leading role in the control of the porosity.

     

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