面支撑橡胶混凝土浮置板轨道动力特性的细观分析

Mesoscale investigation of the dynamic performance of a full-surface supporting floating slab track made of rubberized concrete

面支撑浮置板轨道是浮置板轨道体系中的一种,它具有较好的隔振性能,属于中高等级轨道减振措施。目前,在城市轨道交通工程中具有较多的应用。橡胶混凝土是一种环保型材料,能够很好地解决废弃轮胎带来的环境污染问题,同时,其具有优秀的动力性能。鉴于此,提出将面支撑浮置板轨道与橡胶混凝土结合,即用橡胶混凝土浇筑面支撑浮置板。为了能从宏观与细观2个尺度对面支撑浮置板轨道进行动力分析,采用几何本征骨料混凝土细观建模方法对面支撑橡胶混凝土浮置板轨道进行构建。通过宏观尺度与细观尺度的分析,结果表明:相较于普通混凝土面支撑浮置板轨道,橡胶混凝土面支撑浮置板轨道具有更好的减振效果。随着橡胶含量的增大,橡胶混凝土面支撑浮置板轨道的隔振与耗能作用得到进一步提高。橡胶相较于骨料,振动衰减更快,橡胶颗粒的高阻尼发挥了主要作用。应力主要通过骨料和砂浆进行传递,骨料发挥核心作用,橡胶受力很小,且随着橡胶含量的增加,骨料与砂浆间的力分配比例发生改变,砂浆分配的力得以提高。

Floating slab track with surface support is a type of floating slab track system,which has relatively good vibration isolation performance and belongs to medium and high-grade track vibration reduction measures.At present,it is widely used in urban rail transit engineering.Rubberized concrete is an environment-friendly material,which can well solve the environmental pollution problem caused by waste tires.In addition,it has excellent dynamic performance.In view of this,this paper proposed the combination of surface-supported floating slab track and rubberized concrete,i.e.,rubberized concrete wasused to pour surface-supported floating slab.In order to carry out macro-and meso-scaledynamic analysis for surface-supported floating slab,the Mesoscale Concrete Model with Real Geometry Aggregate(MCM-RGA)was used to construct the track of surface-supported rubberized concrete floating slab.Through the analysis of macro-scale and meso-scale,it is concluded that as comparedto theordinary concrete surface supported floating slab track,rubberized concrete floating slab track has better vibration reduction effect.In addition,with the increase of rubber content,the vibration isolation and energy dissipation of rubberized concrete floating slab track are further improved.As compared to the aggregate,the vibration attenuation of rubber is faster,and the high damping of rubber particles plays a major role.Stress is mainly transmitted through aggregate and mortar,aggregate plays a core role,and rubber bears little force.Moreover,with the increase of rubber content,the force distribution ratio between aggregate and mortar changes,and the force distributed by mortar increases.