中文摘要：

为研究季节冻土区铁路路基在不同冻结时期振动特性,针对典型深季节冻土区大庆分别在冻结期、春融期和正常期进行列车行驶路基振动加速度的现场监测。研究结果表明：1季节冻区路基振动加速度有效值衰减速曲线可用负指数函数拟合;2路基振动强度受列车类型、行驶速度、列车编组、列车载重等因素共同影响;3受环境温度变化的影响,在冻结期自路基基床表层向下冻结,这部分冻结层使路基强度和刚度增加,阻尼比减小,因而导致加速度幅值在纵向和竖向被放大而在水平方向被抑制;4在春融期自基床表层向下开始解冻,由于其下部土体仍处于冻结状态,融化产生的水分无法及时从底部排出,于是形成饱水层使结构层强度大大降低,此时在上部列车荷载作用下,加速度幅值在纵向和竖向被抑制而在水平略有增加。

英文摘要：

To investigate the dynamic characteristics of ground vibrations induced by moving vehicles in a seasonally frozen region, three field experiments are carried out in the Daqing area of China in various periods throughout the year, in spring, summer and winter, respectively. The results show that： （1） The negative exponent function is employed to fit the vibration attenuation laws of subgrade, and the fitting parameters are provided. （2） The acceleration response amplitudes are influenced by train types, train formation, travel speed and train load together. （3） In the frozen period, owing to the fact that the frozen embankment surface layer increases the rigidity of the system and reduces the energy dissipation capacity, the vibration responses in vertical and longitudinal directions are amplified rather than those in the unfrozen and thawing period. In the same reason, the frozen embankment surface layer certainly restricts the lateral vibration role and reduces its response. （4） In the spring melting period, the permafrost melts in two ways, and there is still a certain thickness of the frozen layer in the middle of the embankment, which will prevent the water content in the embankment surface from penetrating and will melt in spring. So the strength and stiffness greatly decrease, and under the train load, the acceleration amplitudes are reduced in the vertical and longitudinal directions and enhanced in the lateral direction.