重载铁路路基粗粒土填料回弹特性试验研究

Resilient Characteristics Test of Coarse-grained Soil Filler for Heavy Haul Railway Subgrade

粗粒土填料广泛应用于重载铁路路基基床层,填料的物理和应力状态对重载铁路路基的回弹特性有重要的影响。为研究粗粒土填料在列车循环荷载作用下的回弹特性,开展一系列循环荷载作用下的大型动三轴试验,分析粗粒土填料在不同含水率、动应力幅值、循环振次、围压条件下回弹模量的变化规律。结果表明:饱和稳定试样,回弹模量约在1000圈左右达到稳定微增长状态,非饱和稳定试样,回弹模量随循环振次的增加呈现出持续增长状态。回弹模量随着动应力幅值和围压的增大而增大,随着含水率的增大而减小。围压和动应力幅值越大,粗粒土回弹模量随含水率的增加下降得越显著。研究结果对重载铁路粗粒土填料回弹特性的认识与回弹模量设计值的取用具有重要参考价值。

The physical and stress state of coarse-grained soil filler,which is widely used in the subgrade bed of heavy-haul railway,has an important influence on the resilient characteristics of heavy-haul railway subgrade.In order to study the resilient characteristics of coarse-grained soil filler under train cyclic load,a series of large-scale dynamic triaxial tests under cyclic load were carried out to analyze the change rule of resilient modulus of coarse-grained soil filler under different water content,dynamic stress amplitude,cyclic vibration times and confining pressure conditions.The results show that for saturated stable samples,the resilient modulus reaches a stable and slightly increased state at about 1000 cycles,while for unsaturated stable samples,the resilient modulus shows a continuous growth state with the increase of cyclic vibration times.Resilience modulus increases with the increase of dynamic stress amplitude and confining pressure,and decreases with the increase of water content.The larger the confining pressure and the amplitude of dynamic stress are,the more significant the decrease of the modulus of resilience of coarse-grained soil filler with the increase of water content.The research results have important reference value for the understanding of the resilient characteristics of coarse-grained soil filler and selecting the design value of resilient modulus for heavy-haul railway.