列车引起的地基动应力特性

Characteristics of train-induced dynamic stresses in ground

为分析列车引起的地基动应力特性,用移动荷载作用下的弹性地基 Euler-Bernoulli 梁模型计算得到地基表面与路堤之间的反力。将其视为作用于地基表面的移动面荷载,以单位移动荷载引起的半空间地基内部应力解为基础,对反力在作用空间上进行积分,得到了列车速度小于地基中 Rayleigh 波速时列车荷载在地基中引起的稳态应力响应解答。给出了应力随空间坐标和时间的变化,分析了应力的特性及分布规律。发现列车经过时在地基中产生的动应力是循环应力,具有明显的偏移应力。竖向动应力的影响范围随着列车速度的增大而不断增大。

In order to analyze characteristics of stresses in ground induced by train,train-induced reaction force between ground surface and embankment was calculated based on Euler-Bemoulli beam on elastic foundation under moving loads.Exerting the reaction force on the ground surface,the corresponding steady-state stresses in ground were obtained by integrating the basic solution of a moving point load on an elastic half-space surface.The results are valid only for train speed lower than Rayleigh wave velocity in ground.The variation of stresses with spatial coordinates and time was presented.Characteristics and distribution rules of stresses were studied.It is found that the dynamic stresses seem to be a kind of particular cyclic load with deviatoric stress With train speed increasing,the effective range of vertical stresses increases continuously.