Discrete element modeling(DEM) study on effect of gradation and morphology on shear strength behavior of rock debris as embankment fill materials

被引：0
|
作者：
Hua W. [1 ]
Xiao Y. [1 ,2 ]
Wang M. [1 ]
Zheng J. [3 ]
Wang X. [1 ]
Chen X. [1 ,2 ]
机构：
[1] School of Civil Engineering, Central South University, Changsha
[2] Key Laboratory of Engineering Structure of Heavy Railway, Central South Universit, Changsha
[3] Department of Civil, Construction and Environmental Engineering, Iowa State University, Ames
来源：
Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology) | 2021年 / 52卷 / 07期
基金：
中国国家自然科学基金;
关键词：
Direct shear tests; Discrete element method; Gradation; Particle morphology; Rock debris from tunneling;
D O I：
10.11817/j.issn.1672-7207.2021.07.020
中图分类号：
学科分类号：
摘要：
In order to explore the feasibility of rock debris used for subgrade filling, three-dimensional shape reconstruction of particles was realized based on computer vision, and the geometric shape parameters including angularity index and flat and elongated ratio, particle size and its distribution were obtained. The effects of gradation and particle morphology on the shear strength behavior of rock debris were studied from large-scale direct shear tests with different levels of normal stress. Further, the discrete element model(DEM) of laboratory direct shear tests was established by using element shape library digitized from real particles and calibrated from laboratory test results. The micro-mechanical characteristics including particle movement, inter-particle contact force network, fabric evolution, and coordination number during the shearing process were simulated and linked to the macro-scale shear behavior. The results show that particles of rock debris with larger angularity index and flat and elongated ratio exhibit greater shear strength. A significant positive correlation was found between the median diameter and shear strength. Specimens of rock debris with a larger median diameter and wider size distribution show stronger inter-particle interaction with the increase of angularity index and greater tendency of particle sliding with the increase of flat and elongated ratio. The ratio of residual shear stress to peak shear stress increases with increasing angularity index and decreasing flat and elongated ratio. Specimens of rock debris with smaller angularity index and larger flat and elongated ratio show better compaction, greater levels of initial deformation modulus, and shear-induced volume dilatancy. © 2021, Central South University Press. All right reserved.
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页码：2332 / 2348
页数：16
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