混合集料中颗粒间接触应力的离散元法分析  

Analysis on the internal contact stresses among aggregates in mixture based on the discrete element method

作　　者：韩海峰 田小革[2] 李新伟 吴栋[2] 李谟忍 

机构地区：[1]广州市高速公路有限公司,广东广州760000 [2]长沙理工大学交通运输工程学院,湖南长沙410004

出　　处：《交通科学与工程》2016年第1期33-38,共6页Journal of Transport Science and Engineering

基　　金：国家自然科学基金项目(50408007;50878032);广东省交通运输厅科技项目(2013-02-013)

摘　　要：采用离散元程序PFC2D,对骨架空隙结构型混合集料PA-13和悬浮密实型混合集料AC-13的数字试件中的内部应力状态进行了分析,以研究具有不同内部结构组成的混合集料中颗粒间接触应力状态的差异。提出了根据混合集料级配生成二维数字试件的方法。选用PA-13和AC-13级配中值的混合集料进行逐级加载的压缩试验,并应用PFC2D对生成的对应数字试件进行相同加载条件的虚拟压缩试验,通过调整混合集料数字试件的微观参数,使模拟得到的荷载-位移关系与实测结果间的误差满足要求,从而得到这2种级配混合集料数字试件的微观参数。将已获得的混合集料微观参数进行虚拟的压碎值试验。研究结果表明:在压碎值试验荷载下,PA-13型级配混合集料中颗粒间的法向平均接触力和最大接触力分别是AC-13型级配混合集料的1.71倍和1.28倍。为保证骨架空隙型混合集料内部结构的稳定性,提出了提高该种混合集料中所用粗骨料的压碎值标准。The discrete element code, PFC2D, was used to study the contact stresses among aggregates in asphalt mixtures with different internal structural skeleton.Firstly, the method to generate a 2-D digital specimen according to the mixture gradation was put forward. Two gradation mixtures with different internal structural skeleton, PA- l3, with skeleton-gap structure, and AC- 13, with suspension-dense structure, were de- signed.The compression tests loading step by step were tested on two mixtures.The cor- responding virtual compression tests were conducted using PFC2D.The microscopic pa- rameters of the mixtures were obtained by adjusting their values to make the error be- tween the simulated load-displacement and that of the measured. The virtual crushing value tests were conducted using PFC2D with the obtained microscopic parameters. It was shown that the average normal contact force and the maximum contact force in PA-13 is 1.71 times and 1.28 times higher than those in AC-13.Therefore, the crush- ing value of the coarse aggregate used in skeleton-gap type asphalt mixture should be higher than that used in the suspension-dense type of the asphalt mixture.

关 键 词：沥青混合集料 内部接触应力状态 离散元法 级配 压碎值 

分 类 号：U416.217[交通运输工程—道路与铁道工程]