基于高速铁路路基冻胀的轮轨动力响应研究

季节性冻土区高速铁路无砟轨道路基冻胀,影响了列车运行的安全性、舒适性以及无砟轨道主体结构的服役性能。为研究路基冻胀和高速行车荷载组合效应下的轮轨动力响应,建立了车辆-轨道-路基冻胀耦合动力学模型,对路基不同冻胀幅值、冻胀位置和行车速度下CRTSⅠ型板式无砟轨道轮轨动力响应及轨道结构受力进行分析。结果表明:冻胀发生区段轮轨动力响应增大,列车以350 km/h运行时的安全性和舒适性满足冻胀管理标准要求,但轮轨力随冻胀幅值和速度的增加而增大;轨道板和底座板振动加剧,在计算冻胀波长和幅值范围内,离缝处轨道板振动加速度峰值超过动态验收标准要求,容易引起离缝处CA砂浆层及路基基床表层伤损破坏,且轨道板、底座板振动加速度随行车速度增加而增大;轨道结构动应力和列车荷载传递关系密切,路基冻胀状态下列车荷载引起轨道板和底座板处于交替和交变的拉压受力状态,需要在设计中提出控制裂纹的措施,行车速度对短波冻胀时轨道结构受力影响较小。

Dynamic response of wheel-rail based on frost heave of high-speed railway subgrade

Frost heave of high-speed railway ballastless track subgrade in seasonal frost areas affects the safety and comfort of train operation and service performance of ballastless track’s main structure.In order to study dynamic response of wheel-rail under the combination effect of subgrade frost heave and high-speed driving load,the vehicle-track-subgrade frost heave coupled dynamic model was established to analyze the wheel-rail dynamic response of CRTSI type slab ballastless track and track structure’s stress state under different frost heave peak values,frost heave positions and train speeds.The results showed that dynamic response of wheel-rail increases in frost heave regions,the safety and comfort of train operation at speed of 350km/h meet the standard requirements of frost heave management,but wheel-rail force increases with increase in frost heave peak values and operation speed;vibration of track slab and base plate intensifies;within calculated range of frost heave wavelength and amplitude,peak value of vibration acceleration of track slab at gaps exceeds dynamic acceptance standard requirements,and it is easy to cause damage and failure of CA mortar layer and subgrade bed surface at gaps,vibration accelerations of track slab and base plate increase with increase in driving speed,dynamic stress of track structure is closely related to train load transmission;train load under state of subgrade frost heave causes track slab and base plate to be in tension and compression alternating state,and proposing measures in design is needed to control cracks;train speed has less effects on track structure stress during shortwave subgrade frost heave.