X img

官方微信

img

群号:冰川冻土交流群

QQ群:218834310

高级检索
作者投稿 专家审稿 编辑办公 编委办公 主编办公

冰川冻土 ›› 2020, Vol. 42 ›› Issue (4): 1267-1274.doi: 10.7522/j.issn.1000-0240.2020.0103

• 寒区工程与灾害 • 上一篇    下一篇

碎石集料变形机理的块体元数值试验分析

马正涛1,2,3(), 李双洋2(), 赵永春2, 李根2   

  1. 1.甘肃省公路局, 甘肃 兰州 730000
    2.中国科学院 西北生态环境资源研究院 冻土工程国家重点实验室, 甘肃 兰州 730000
    3.兰州大学 土木工程与力学学院 西部灾害与环境力学教育部重点实验室, 甘肃 兰州 730000
  • 收稿日期:2017-12-19 修回日期:2018-03-24 出版日期:2020-12-31 发布日期:2021-01-21
  • 通讯作者: 李双洋 E-mail:m18394818398@163.com;lisy@lzb.ac.cn
  • 作者简介:马正涛(1994 - ), 男, 甘肃临夏人, 助理工程师, 2019年在兰州大学获硕士学位, 从事路基数值模拟研究. E-mail: m18394818398@163.com
  • 基金资助:
    国家重点研发计划项目(2018YFC0808401);国家自然科学基金项目(41672315);中国科学院青年创新促进会优秀会员项目(Y201975)

Deformation process and mechanisms of crushed rock aggregate analyzed by numerical experiment of discrete element method

Zhengtao MA1,2,3(), Shuangyang LI2(), Yongchun ZHAO2, Gen LI2   

  1. 1.Highway Bureau of Gansu Province,Lanzhou 730000,China
    2.State Key Laboratory of Frozen Soil Engineering,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China
    3.Key Laboratory of Mechanics on Disaster and Environment in Western China,Ministry of Education,College of Civil Engineering and Mechanics,Lanzhou University,Lanzhou 730000,China
  • Received:2017-12-19 Revised:2018-03-24 Online:2020-12-31 Published:2021-01-21
  • Contact: Shuangyang LI E-mail:m18394818398@163.com;lisy@lzb.ac.cn

摘要:

块碎石作为道砟材料能够分散列车动荷载, 加之其内部含有大量空隙, 具有良好的对流换热特性, 作为冷却冻土路基的材料在青藏铁路建设中被广泛使用。但在列车荷载的作用下, 碎石集料会发生压密、 变形乃至破碎从而影响冷却效果。因此, 研究碎石层的变形过程及机理具有十分重要的现实意义。基于块体离散元法, 对块碎石集料的三轴剪切试验进行了数值分析, 将所得应力-应变曲线与室内试验结果进行了对比, 发现两者能较好地吻合, 说明块体离散元法能够较好地模拟块碎石集料的受力变形过程。结果表明: 增大围压或块体粒径, 块体单元受到的作用力加强, 集料的偏应力强度和抗剪强度值也随之增大。碎石块体在剪切作用下沿其接触面滑动分离, 形成X形剪切带是集料变形的主要形式, 此外在径向方向出现不同程度的扩张。基于试验和块体元研究路基碎石层的思路和方法可为今后评估青藏铁路碎石路基的热力稳定性提供理论依据和参数储备。

关键词: 块体离散元, 碎石集料, 冻土路基, 应力-应变, X形剪切带

Abstract:

As a ballast material, the crushed rock is able to disperse train dynamic load, and it has a distinct characteristic of good convective heat transfer characteristics. Therefore, it was extensively used to cool the permafrost embankment in Qinghai-Tibet Railway. However, the crushed rock layer is compacted and even crushed under train load, so the cooling effect of the crushed rock layer decreases. For this reason, it is very important to study deformation process and mechanisms of the crushed rock layer. In this study, numerical simulations on triaxial tests of the crushed rock were carried out by the discrete element method (DEM). A comparison between experimental and numerical results show they well agree with each other, which implies the DEM can simulate the deformation process of the crushed rock. Moreover, the numerical result indicates that the deviatoric stresses and shear strength values increase with confining pressure and block size. The mainly deformation of the crushed rocks is an X shear band formed by sliding and separating along the contact surface under the shear action. In addition, there are different degrees of expansion in the radial direction. The research idea and method of the crushed rock layer in this study will be useful for evaluating thermodynamic stability of the crushed rock embankment of the Qinghai-Tibet Railway.

Key words: discrete element method (DEM), crushed rock aggregate, permafrost embankment, stress-strain, X shear band

中图分类号: 

  • TU471+.7