混凝土徐变对柔性车体列车-桥梁系统动力响应影响分析

摘要

The creep of simply-supported concrete beam on high-speed railway will induce additional deformation of the track structure and affect train operation quality.A train-bridge sys-tem which takes car-body flexibility into consideration is therefore established.Taking the 32 m and 24 m simply-supported prestressed concrete beams,which are the common span beams,on high-speed railway as a study case,the additional deformation of CRTS Ⅲ ballastless slab track induced by concrete creep and its effect on the safety and comfort of vehicles running through the deformed bridge are studied.The calculation results show that prolonging the track construction time can effectively prevent additional deformation of track structure induced by creep from ex-ceeding code limit.The creep deflection makes the convex angles appear around beam end of the track structure,when a wheel goes through the convex angle,the wheel-rail force will decrease sharply,which could even induce wheel-rail separation.The influence of creep on the comfort in-dex is far greater than that on the safety index,and the influence of creep on the vehicle operation comfort could be underestimated when ignoring car-body flexibility.%为了解决高速铁路混凝土简支梁桥徐变引起桥上轨道结构发生附加变形,进而影响桥上列车运营品质的问题,建立了柔性车体列车-桥梁系统动力分析模型,并以高速铁路常见跨度32 m和24 m预应力混凝土简支梁为例,分析了混凝土徐变对桥上CRTSⅢ 型无砟轨道结构附加变形的影响特点,并进一步研究了轨道结构附加变形对桥上列车运行安全性及平稳性的影响规律.研究结果表明:延长铺轨时间可有效防止混凝土桥梁工后徐变引起的轨道结构附加变形量超出规范限值;梁体徐变下挠情况会使梁端区域的轨道结构出现凸起折角,列车通过这一折角时轮对动轴重会急剧减小,可能出现"轮轨分离";梁体徐变对运行舒适性指标的影响远大于对运行安全性指标的影响,同时,忽略车体柔性会低估梁体徐变对车辆运行舒适性的影响.