高速列车荷载作用的动三轴试验模拟

Simulation of high-speed train load by dynamic triaxial tests

动三轴试验是目前最常见的获取高速列车荷载作用下土体变形、强度特性的室内试验手段。为探讨模拟高速列车荷载时加荷模式、排水条件、加荷次数等因素对试验结果的影响,利用GDS动三轴仪,对高速铁路沿线典型黏性土进行高振次循环动三轴试验,研究不同试验条件下试样变形、孔压发展规律和临界循环应力比的变化。研究建议可采用半正弦波在排水条件下进行动力试验模拟高速列车荷载,获得地基土体的最大可能变形和临界动应力比,从而简化试验过程,大大缩短试验时间。

The dynamic triaxial tests are the most conventional laboratory method to obtain the deformation and the strength properties for soils.A series of high cycle dynamic triaxial tests are conducted on a typical silty clay,the ground soil along high-speed lines.The comparisons among dynamic strain,pore pressure and the critical dynamic stress ratio of the test samples are made to study the effects of simulation difference between the in-situ and simplified test conditions,such as dynamic loading mode,drainage condition and duration of cyclic loading.The deformation,the pore pressure,the volumetric changes and the critical dynamic stress ratio under various test conditions are presented.According to the test results,to analyze the dynamic behavior of soft clay under high-speed train loading,the dynamic test with half sinusoidal waves under drainage condition is suggested to simplify the test procedure in laboratory studies.