基于PFM-LBM的冻土渗透特性介观尺度数值研究OA
Numerical simulation of permeability characteristics of saturated frozen soils based on PFM-LBM
土体冻胀现象的核心是冻土中水分的迁移和相变,而冻土渗透系数是理解该过程的关键参数.冻土对温度和流体的高度敏感性使得物理实测其渗透系数存在很大困难,因此从介观尺度开发可靠的数值分析方法是非常有益的探索.首先利用级配曲线重构了土样的多孔介质结构,从介观尺度提出了一个研究冻土渗透特性的 PFM-LBM 耦合的介观数值方法.基于已有的试验数据和解析模型,对模型进行验证,表明该方法可以高效准确地预测饱和冻土渗透系数.在此基础上研究了未冻水含量、不同成冰方式等因素对冻土渗透特性的影响,结果显示未冻水含量对冻土的渗透系数有显著影响,集中反映在流体相对比界面长度 Rf和迂曲度τf的增加.孔隙填充和颗粒包覆两者成冰方式对冻土渗透系数的影响也存在差异:前者与Rf的联系更加紧密;而后者则是随着未冻水含量的减小,τf的影响越来越突出.
Hydraulic conductivity of frozen soils macroscopically reflects the migration and phase change of liquid in soil,which is the key to the phenomenon of frost-heave.High sensitivity of frozen soil to temperature and fluid presents significant challenges for the physical measurement of its hydraulic conductivity.Therefore,the development of reliable numerical analysis methods at micro level is a valuable exploration.In this study,the structure of the porous medium of soil samples is first reconstructed using gradation curves,and then a numerical method based on PFM(phase field method)and LBM(Lattice Boltzmann method)coupling is proposed to investigate the permeability characteristics of frozen soils at the mesoscale.Based on existing experimental data and analytical models,the proposed model is validated.On this basis,the effects of unfrozen water content and different ice formation methods on the permeability characteristics of frozen soils are studied.The results show that the unfrozen water content has a significant effect on the hydraulic conductivity of frozen soils,which is mainly reflected in the increase of the fluid relative specific interface length Rf and the tortuosity τf.The effect of pore filling and particle coating on the permeability coefficient of frozen soil is different:the former is more closely related to Rf;for the latter,the influence of τf becomes much stronger with the decrease of unfrozen water content.
HU Yuyang;SUN Chenzhang;YAN Han;TENG Jidong;ZHANG Sheng
School of Civil Engineering,Central South University,Changsha 410075,ChinaSchool of Civil Engineering,Central South University,Changsha 410075,ChinaSchool of Civil Engineering,Central South University,Changsha 410075,ChinaSchool of Civil Engineering,Central South University,Changsha 410075,China||National Engineering Research Center of High-speed Railway Construction Technology,Central South University,Changsha 410075,ChinaSchool of Civil Engineering,Central South University,Changsha 410075,China||National Engineering Research Center of High-speed Railway Construction Technology,Central South University,Changsha 410075,China
建筑与水利
饱和冻土相场法格子Boltzmann方法渗透特性介观尺度
saturated frozen soilphase field methodLattice Boltzmann methodpermeability characteristicsmesoscale
《岩土工程学报》 2026 (1)
54-64,11
国家重点研发计划(2022YFB2603301)国家自然科学基金项目(52178376)This work was supported by National Key Research and Development Program of China(Grant No.2022YFB2603301),and National Natural Science Foundation of China(Grant No.52178376).
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