32m高速铁路简支梁桥铺轨后残余徐变上拱限值研究

运用Midas软件分别建立简支梁桥-CRTSⅡ型板式无砟轨道空间耦合静力学模型和车-线-桥耦合动力学模型,进行32m高速铁路简支梁桥铺轨后残余徐变上拱限值研究。结果表明:桥梁残余徐变变形是影响32m波长周期性高低不平顺的主要因素;随着桥梁残余徐变幅值增加,长钢轨的附加不平顺呈线性增大,桥梁残余变形幅值为10mm时,钢轨的上拱变形量可达9.8mm;行车速度为380km·h^-1、桥梁残余徐变上拱幅值由3mm增加至10mm时,车体的垂向加速度峰值由0.275m·s^-2增加至1.159m·s^-2,旅客乘坐舒适度指标由1.549逐渐增加至3.105;当桥梁残余徐变幅值为8.0mm,在280~380km·h-1车速范围内,旅客乘坐舒适度指标达到3.108,桥梁梁端振动加速度达到5.217m·s^-2,已超出规范限值,因此建议高速铁路32m简支梁桥铺轨后其残余徐变上拱限值按7.0mm控制,为避免残余徐变限值的改变对桥梁设计方案产生显著影响,可通过适当延后铺轨时间保证桥梁残余徐变变形满足限值要求。

Study on Residual Creep Arching Threshold of 32m Simply-Supported Beam Bridge of High Speed Railway after Track Laying

The space coupling statics model of simply supported beam bridge-CRTSⅡslab ballastless track and vehicle-track-bridge coupling dynamics model was respectively established with Midas software.The residual creep arching threshold of a 32 msimply supported beam bridge for high speed railway after track laying was studied.Results show that the residual creep deformation of the bridge is the main factor which causes the periodic irregularities of 32 mwave length.With the increase of the residual creep amplitude of bridge,the additional irregularities of long rail increase linearly.When the residual deformation amplitude of the bridge is 10 mm,the arching deformation of the rail can reach 9.8 mm.As the running speed is 380 km·h^-1 and the amplitude of residual creep arching of the bridge increases from 3 to 10 mm,the peak value of the vertical acceleration of car body increases from 0.275 to 1.159 m·s^-2,and the passenger ride comfort index increases gradually from 1.549 to 3.105.When the residual creep amplitude of the bridge is8.0 mm,the passenger ride comfort index reaches 3.108 and the vibration acceleration at the end of the beam reaches 5.217 m·s^-2 which exceed the code limit when the train speed is between 280 and 380 km·h^-1.It is suggested that the residual creep arching threshold of 32 msimply supported beam bridge for high-speed railway should be controlled as 7.0 mm after track laying.To avoid the significant influence of the change of the design scheme of the bridge due to the residual creep threshold,the residual creep deformation of the bridge can be ensured to meet the requirements for the threshold by properly delaying the track laying time.