列车振动荷载作用下黄土动力特性分析

Analysis of Loess Dynamic Characteristics under Train Vibrating Load

利用GDS动三轴仪,根据列车振动荷载"长持时,小振幅"的特点探究黄土动力特性。试验结果表明:在动应力过程中,动孔压波动变化且单调增长;土的动应变随着振次的增加而明显变大,且动应变相对动应力作用滞后,说明黄土的滞后性;试样的原有强度逐渐减小,最后剩余强度大幅度丧失。试样在3700次左右发生破坏。由此可见,在列车循环荷载作用下的黄土路基容易产生较大沉降,需合理预测和控制黄土在振动作用下的沉降。

With GDS three dynamic triaxial apparatus and according to the ＂ long duration,small amplitude＂ code of train vibration load,the dynamic characteristics of loess are explored. Test results have showed that in the process of dynamic stress,dynamic pore water pressure fluctuating changes and monotonically increases,with dynamic strain of soil obviously much larger with the increasing of vibration times,thus the effect of dynamic strain is lagging behind that of dynamic stress which implies the hysteretic nature of loess,the original strength is reducing and finally its residual strength suffers great loss. And the destruction model of sample occured at about 3700 times. Roadbed of loess can easily generate great sediment upon the train looping loading effect,so it＇s necessary to reasonably predict and control the sediment of loess considering the influence of vibration.