脏污对道床剪切性能影响及评估指标的离散元分析  

SHEAR BEHAVIOR ANALYSIS OF FOULED RAILROAD BALLAST BY DEM AND ITS EVALUATION INDEX

作　　者：徐旸[1,2] 高亮[1,2] 井国庆[1,2] 蔡小培[1,2] 罗奇[1,2] 

机构地区：[1]北京交通大学土木建筑工程学院,北京100044 [2]轨道工程北京市重点实验室,北京100044

出　　处：《工程力学》2015年第8期96-102,共7页Engineering Mechanics

基　　金：国家自然科学基金高铁联合基金重点项目(U1234211);北京交通大学基本科研业务费项目(2013YJS095);中国铁路总公司科技研究开发计划项目(2013G009-B);北京高等学校青年英才计划项目(YETP0559)

摘　　要：对国内外典型的道床脏污评估指标进行了综合分析。基于已有研究成果,提出了新的道床评估指标PFI。采用离散元法建立了基于精细道砟仿真单元的直剪数值模型,对不同脏污程度道床的剪切性能及PFI的合理性进行了研究,研究结果表明:脏污会显著降低道床的抗剪性能,其下降幅度与道床的脏污程度有关;脏污材料的粒径对道床剪切性能影响明显,且在材质相同的情况下,小粒径的脏污会引起道床剪切性能的进一步降低;相比于已有评估指标VCI,PFI能够考虑脏污材料粒径的影响,从而更准确的评估道床脏污情况。Typical evaluation indices of fouled ballast are discussed and a new one, PFI, is proposed. A DEM simulation of direct shear box based on delicate ballast model is performed to study the shear performance of fouled ballast at various levels and to evaluate the rationality of the PFI index. The results indicate that the shear stress of ballast decreases observably due to fouling, which depends on the fouling degree. In addition, the particle size of fouling also influences the shear performance of ballast. The shear performance of ballast drops as the fouling particle size decreases for the same material. Compared with VCI, PFI can take the effects of fouling particle size into account. Therefore, PFI can evaluate the fouling level of ballast more accurately.

关 键 词：铁路道床 脏污评估指标 离散元法 脏污率 直剪 

分 类 号：U213.7[交通运输工程—道路与铁道工程]