摘要
基于CFD-DEM方法,开展了不同细粒含量(质量分数,下同)与间断比下不连续级配砂砾土渗蚀数值试验,从宏细观角度研究了细粒含量与间断比对渗蚀的联合作用机理。研究结果表明:土体侵蚀率随间断比的增大而增加,当间断比G较小(G<3)时,土样内部未发生颗粒迁移现象,表现出较好的内部稳定性,与KéZDI判别准则吻合。当细粒含量不同时,间断比对渗蚀宏细观特征行为影响程度差异显著。当细粒含量较低(如15%)时,细颗粒较少参与土体内部应力传递,渗蚀过程中土样体积、强接触力链以及细颗粒应力分担系数几乎不发生改变,粗颗粒间孔隙直径增大,导致更多弱接触细颗粒流失,从而使得侵蚀率随间断比增加;相反,当细粒含量较高(如35%)时,参与应力传递的细颗粒比例相对较高,间断比增大导致粗颗粒数量减少,细颗粒流失易导致整个土体力链体系破坏,引起骨架颗粒重组变形,进而释放更多约束颗粒,加剧颗粒流失,故侵蚀率增加是孔隙直径增大和渗蚀过程中土骨架不断发生变形共同作用的结果。
Based on the CFD-DEM method,numerical simulations in gap-graded sandy gravels with different fines contents(mass fraction,similarly hereinafter)and gap ratios(GR)were carried out to investigate the combined effects of fines content and gap ratio on suffusion from macro and micro perspectives.The results show that the erosion rate increases with increasing GR.No particle migration occurs within the soil samples when the GR is smaller than 3,demonstrating good internal stability.Furthermore,GR has a notable effect on suffusion behavior when the fines content(FC)varies.For instance,with a relatively low FC(e.g.,FC is 15%),fine particles play a limited role in stress transfer.During the erosion process,the sample volume,the strong contact force chain network,and the stress reduction coefficient remain relatively unchanged.This indicates that the increase in erosion rate is primarily attributed to the increased pore diameter among coarse particles and the loss of weak-contact fines.On the contrary,when the FC is relatively high(e.g.,FC is 35%),the fine particles actively participate in stress transfer,and an increase in GR can result in a reduction in the number of coarse particles.The loss of fine particles easily leads to the collapse of the entire force chain system,causing the skeleton particles to deform and rearrange,releasing more constrained particles and intensifying the loss of fine particles.Therefore,the main reason for the increasing erosion rate is the combined effect of the increasing pore diameter among coarse particles and the continuous deformation of the soil skeleton during suffusion.
作者
刘垒雷
邓刚
李维朝
陈锐
周超
徐立强
LIU Leilei;DENG Gang;LI Weichao;CHEN Rui;ZHOU Chao;XU Liqiang(School of Civil and Environmental Engineering,Harbin Institute of Technology,Shenzhen 518055,China;Guangdong Provincial Key Laboratory of Intelligent and Resilient Structures for Civil Engineering,Shenzhen 518055,China;State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin,China Institute of Water Resources and Hydropower Research,Beijing 100038,China;Department of Civil and Environmental Engineering,Hong Kong Polytechnic University,Hong Kong 999077,China)
出处
《中南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2024年第7期2677-2689,共13页
Journal of Central South University:Science and Technology
基金
国家重点研发计划项目(2021YFC3001000)
国家自然科学基金资助项目(52278339)
深圳市科技计划项目(KQTD20210811090112003)
中国水利水电科学研究院基本科研业务费资助项目(GE0145B032021,GE110145B0032023)。
