列车荷载下冻土路基非平稳随机振动分析的时域显式法北大核心CSCD

随着我国冻土地区铁路运营里程的不断提升,冻土路基在随机列车荷载作用下的动力响应分析成为了急需解决的工程问题。本文以青藏铁路某路基横断面为例,采用时域显式蒙特卡罗模拟法,计算其在随机列车荷载作用下响应的统计特征。首先,提出列车驶过施加在路基顶面荷载的快速计算方法,并引入轨道不平顺及列车行驶速度两类随机参数,以生成随机分析所需的大量荷载样本。然后,采用数值积分方法将运动方程在时域上进行离散,建立任意离散时刻冻土路基动力响应关于列车荷载的显式表达式。基于该显式表达式,可以高效地实施蒙特卡罗模拟,得到在随机列车荷载作用下路基关键响应的均值、标准差和峰值等统计量。采用该方法,分析了路基在夏冬两个季节不同深度处的随机动力响应,发现在夏季路基浅层中的位移和速度响应最为剧烈。数值算例表明,时域显式蒙特卡罗模拟法在冻土路基随机振动分析中具有理想的计算精度和计算效率。

Non-stationary random vibration analysis of railway embankments in permafrost regions under train loads using the explicit time-domain method

With the rapidly increasing railway operating length in the permafrost regions of China， dynamic analysis of permafrost embankment under random train loads has become an urgent engineering problem to be solved. Taking a cross-section of the embankment of Qinghai-Tibet Railway as an example， this paper adopts the explicit time-domain method to analyze the statistical characteristics of its responses to random train loads. In order to obtain the train load samples， which serve as the inputs in the stochastic analysis， an efficient procedure is proposed incorporating the random parameters of track irregularity and train speed. The numerical integration method is used to discretize the equation of motion in the time domain， and an explicit expression of the dynamic responses of permafrost embankment is established. Based on the established explicit expressions， Monte Carlo simulation can be efficiently conducted， delivering the statistics of the random system outputs， including the mean values， standard deviations and mean peak values of the embankment dynamic responses. Using this method， the random dynamic responses of the permafrost embankment in summer and winter are analyzed. It is found that the displacement and velocity responses in summer are more severe than those in winter. Numerical results indicate that the explicit time-domain method has high accuracy and efficiency in analyzing the random vibration of permafrost embankment.