路基冻胀区双块式无砟轨道动力特性研究

纵连式无砟轨道在路基冻胀区域极易产生轨道结构断裂破坏及结构层离缝等病害。为研究纵连式无砟轨道在路基冻胀状态下的损伤机理,文章建立车辆-轨道-路基冻胀一体化动力学分析模型,对路基冻胀状态下轮轨动力响应特征、轨道结构动力响应特征及影响因素进行分析。结果表明:路基冻胀波长为10 m时,双块式无砟轨道各动力特征达到最大值;冻胀波长大于20 m时,各动力特征逐渐趋于稳定;列车荷载在层间离缝位置处使得轨道结构反弯,轨道结构层顶部纵向拉应力增大;20 m以下冻胀波时,拉应力超过或接近设计强度值;无砟轨道各动力响应特征最大值随冻胀幅值的增加显著增大,季冻区施工及运营期间应控制冻胀幅值增加。

Study on dynamic characteristics of ballastless track double hump slab in frost heave zone roadbed

Longitudinal ballastless track in frost heaving roadbed zone is prone to cause track structure defects including fracture and structural layer separation.In order to study the damage mechanism of longitudinal ballastless track under roadbed frost heaving condition,an interacted dynamic analysis model of integrating vehicle,track,roadbed and frost heaving is established,and this paper analyzes the dynamic response characteristics of wheel/rail,track structure and influencing factors under roadbed frost heaving condition.The results show that:when the frost heaving wavelength of subgrade is 10 m,the dynamic characteristics of double hump ballastless track reach the maximum.When the frost heaving wavelength is greater than 20 m,the dynamic characteristics gradually tend to be stable,the track structure is reversed bending at the position of interlayer separation.While the longitudinal tensile stress at the top of the track structure layer increases and the frost heaving wavelength is less than 20 m,tensile stress exceeds or approaches the designed strength value,the maximum value of dynamic response characteristics of ballastless track increases significantly with the increase of frost heaving amplitude,and the increase of frost heaving amplitude should be controlled during construction and operation in winter season frozen area.