基于几何指标的高速铁路桥上列车地震安全性评判方法

Evaluation method for running safety of train on a high-speed railway bridge based on geometric indexes

地震荷载作用下如何评判桥上列车的行车安全性关系到高速铁路线路的运营安全。基于车轮-钢轨间的几何约束关系,在原有列车-轨道-桥梁-地震分析系统TTBSAS中引入列车行车安全性评判的几何指标—接触点横移量和车轮抬升量,通过输入实测地震波系统研究了接触点横移量和车轮抬升量随地震动强度的变化规律,并提出了基于几何指标的列车地震安全性评判方法。结果表明:采用传统的脱轨系数和轮重减载率指标评判地震作用下桥上列车的行车安全性过于保守;车轮抬升量对地震动强度的变化更敏锐,更适合评判地震作用下桥上列车的行车安全性;依据车轮抬升量将列车的行车安全性划分为安全、危险和脱轨3个状态较为合理,对于该计算条件,当地震动强度为0.1 g时,其安全、危险和脱轨车速分别速为225 km/h、250 km/h、375 km/h。该研究成果为灾变荷载作用下桥上列车的行车安全性评定提供了新思路。

How to judge running safety of train on a bridge under seismic load is related to the operation safety of high-speed railway lines.Here,based on geometric constraint relation between wheel and rail,geometric indexes of train running safety evaluation including contact point transverse shift and wheel vertical rise were introduced into the original train-track-bridgeseismic analysis system(TTBSAS).Through inputting actual measured seismic wave,varyinglaws of contact point transverse shift and wheel vertical rise with variation of seismic intensity were studied,and a train running safety evaluation method based on geometric indexeswas proposed.Results showedthat using traditional indexes of derailment coefficient and wheel load reduction rate to evaluate the running safety of train on a bridge under earthquakeare excessively conservative;wheel vertical rise is more sensitive to variation of ground motion intensity,using it is more suitable to evaluate running safety of train on a bridge under earthquake;according to wheel vertical rise,it is reasonable to divide the train running safety into 3 states of safety,danger and derailment;for calculation conditions here,when the ground motion intensity is 0.1 g,train’s safe running speed,dangerous one and derailment one are 225 km/h,250 km/h and 375 km/h,respectively;the study results provide a new idea for running safety evaluation of train on a bridge under catastrophic loads.