分形粒径分布对颗粒流粒径分选的影响规律  

Effects of fractal particle size distribution on segregation of granular flows

作　　者：李坤[1,2] 王玉峰[1] 程谦恭[1,2,3] 林小龙 LI Kun;WANG Yufeng;CHENG Qiangong;LIN Xiaolong(Department of Geological Engineering,Southwest Jiaotong University,Chengdu,Sichuan 611756,China;Key Laboratory of High-speed Railway Engineering,Ministry of Education,Southwest Jiaotong University,Chengdu,Sichuan 610031,China;State-province Joint Engineering Laboratory of Spatial Information Technology for High-speed Railway Safety,Southwest Jiaotong University,Chengdu,Sichuan 611756,China;China Railway Academy Chengdu Co.,Ltd.,Chengdu,Sichuan 610032,China)

机构地区：[1]西南交通大学地质工程系,四川成都611756 [2]西南交通大学高铁线路工程教育部重点实验室,四川成都610031 [3]西南交通大学高速铁路运营安全空间信息技术国家地方联合工程实验室,四川成都611756 [4]中铁科学研究院有限公司成都分公司,四川成都610032

出　　处：《岩石力学与工程学报》2021年第2期330-343,共14页Chinese Journal of Rock Mechanics and Engineering

基　　金：第二次青藏高原综合科学考察研究专题资助项目(2019QZKK0906);国家自然科学基金资助项目(41941017,41530639)。

摘　　要：高速远程滑坡反粒序及其形成机制是目前研究的热点问题,为进一步探讨该问题,以高速远程滑坡分形粒径分布特征为依据,通过物理模型实验与数值模拟方法,研究不同分形维数颗粒流堆积体的粒径分布特征及其对应的颗粒分选过程,结果表明:随着颗粒流分形维数的增大,细颗粒含量的增加,颗粒流运动过程中不同粒径颗粒的分选作用减弱,导致堆积体中反粒序的发育程度降低;在不同粒径组成条件下,颗粒流前缘及尾部主要呈离散态运动,中部则以密集态为主,仅表面局部颗粒发生离散,颗粒流堆积体中反粒序的形成是多种分选机制综合作用的结果。基于结果分析,高速远程滑坡运动过程中整体不具备颗粒分选的条件,仅在局部范围内可能存在颗粒分选作用。The inverse grading of high-speed and long-runout landslide deposits and its forming mechanisms are hot research topics currently. To further explore these issues,a series of experiments and numerical simulations were conducted to investigate the grain size distribution of the deposits and the corresponding segregation process of granular flows with different fractal dimensions based on the fractal particle size distribution of the deposits. The results show that with increasing the fractal dimension and the enrichment of the fine particles,the segregation process in the granular flow is weakened,resulting in a lower degree of inverse grading in the deposits. For granular flows with different compositions,the leading and tailing edges are highly dispersed,while the main bodies are densely packed with limited dispersion of particles on the flow surface. The formation of the inverse grading in the deposits is attributed to various segregation mechanisms. Based on the analysis,the requirements for segregation cannot be fully satisfied in the emplacement of high-speed and long-runout landslides except for local segregation process.

关 键 词：边坡工程 分形维数 高速远程滑坡 颗粒流 颗粒分选 反粒序 

分 类 号：P642[天文地球—工程地质学]