摘要
研究目的:在基础刚度突变的路桥过渡段,受冲击荷载作用有砟轨道道床道砟破碎比较严重,给线路安全运营和养护维修造成巨大压力,道砟破碎问题越来越受到研究人员关注。现有研究主要采用落锤冲击方法,围绕道砟的级配变化和整体破坏特征开展,而有关道砟几何形状变化的量化研究还比较少见。几何形状是道砟的重要参数,其变化特征对道床性能劣化具有重要影响。因此,本文在道砟冲击试验及宏观分析结果基础上,利用激光扫描和三维图形分析方法,研究道砟几何形状破坏特征和分布规律。研究结论:(1)冲击荷载作用下断裂破坏道砟占比显著增加,棱角破坏和断裂破坏道砟的颗粒占比约为3∶1,随粒径增加,发生断裂的道砟比例增加,块状道砟发生棱角破坏的比例约为针状和片状的2倍,针状、片状道砟发生断裂破坏的比例约为块状的3倍;(2)棱角破坏道砟在棱边、角等处的最大缺失深度通常在5 mm以内,棱角破坏道砟的形状系数随粒径增大而增加,块状道砟形状系数变化率较小,针状和片状道砟形状系数变化率较大,可达块状道砟形状系数变化率的3倍以上;(3)利用比表面积指标可区分两种道砟破坏类型,断裂道砟试样前后的比表面积呈线性关系,截距代表了断裂道砟增加表面消耗冲击能的性能,对断裂面的位置有重要影响;(4)本研究结果可为道床的劣化评估和维修策略制定提供参考。
Research purposes:In the transitional section of road and bridge with sudden change of foundation stiffness,the ballast breakage is serious under the impact load,which causes great pressure to the safe operation and maintenance of the ballast track.The drop hammer impact test is mainly adopted and gradation change and overall damage characteristics of the ballast are mainly studied by current research.However,the quantitative study on the geometric shape change of the ballast is relatively rare.The geometric shape of ballast is an important parameter of material,and its variation characteristics have an important influence on the deterioration of ballast performance.Therefore,based on the ballast impact test,this paper studies the damage characteristics and distribution law of the ballast shape by laser scanning and three-dimensional graphic analysis.Research conclusions:(1)The proportion of fractured ballast increases significantly under impact load,and the proportion of broken particles in angular and fractured ballast is about 3∶1.The proportion of fractured ballast increases with the increase of particle size.The proportion of angular damaged ballast is about twice that of needle and sheet ballast.The proportion of fractured needle and sheet ballast is about 3 times that of block ballast.(2)The maximum loss depth of ballast in the edge,corner,etc.,is usually within 5 mm.The shape coefficient of the angular damaged ballast increases with the increase of particle size,the change rate of the shape coefficient of the block ballast is small and the change rate of the needle and sheet ballast is larger,which is about more than 3 times of the block ballast.(3)The specific surface area index can be used to distinguish the two types of ballast breakage.The relationship of specific surface area for fractured ballast before and after test is linear,and the intercept represents the performance of the fractured ballast for consumption of impact energy,which has an important effect on the location of the fracture surface.(4)The research results can provide reference for the assessment and maintenance of the deterioration of the ballast bed.
作者
常建梅
田喜龙
冯怀平
CHANG Jianmei;TIAN Xilong;FENG Huaiping(Key Laboratory of Roads and Railway Engineering Safety Control,Shijiazhuang Tiedao University,Shijiazhuang,Hebei 050043,China)
出处
《铁道工程学报》
北大核心
2025年第7期38-42,49,共6页
Journal of Railway Engineering Society
基金
国家自然科学基金项目(52272439,U22A20233)
中央引导地方项目(236Z5409G)。
关键词
冲击荷载
道砟
几何形状
破坏特征
三维图形
impact load
ballast
geometrical shape
broken character
3D graphics
