重载铁路路基低液限粉土的动力特性

Dynamic Characteristics of Low Liquid-limit Silt in Subgrade of Heavy Haul Railway

针对朔黄重载铁路路基不同饱和度的低液限粉土填料,开展了不同围压、不同动应力幅值的动三轴试验。分析了围压、饱和度、固结比等因素对低液限粉土动力特性的影响。结果表明:低液限粉土填料的动剪应力随围压的增大近似线性增大,随饱和度的增大而降低;抗剪强度随饱和度的降低而增大;破坏振动次数越大,对应的液化应力比越小;饱和试样的液化应力比随围压增加而增加,非饱和试样则反之;动弹性模量随围压和固结比的增大而增大,但饱和度对于动弹性模量的影响规律不明显。研究结果可供重载铁路路基动力特性评价和加固设计参考。

The dynamic characteristics of the low liquid-limit silt in the subgrade of Shuo-Huang Heavy Haul Railway were studied in this paper. A series of dynamic triaxial tests with different confining pressures and dynamic stress amplitudes were carried out. The influence of confining pressure,degree of saturation,and consolidation ratio on the dynamic characteristics of the low liquid-limit silt was analyzed. The results show that the dynamic shear stress is approximately linearly increased with the confining pressure but decreased with the saturation ratio. The shear strength increases as the saturation ratio decreases. The more failure cycles,the less stress ratio of liquefaction. As for the saturated samples,the stress ratio of liquefaction is increased with the confining pressure; however, it is the opposite for the unsaturated samples. The dynamic modulus is increased with the confining pressure and the consolidation ratio,while the influence of the saturation degree on the dynamic modulus is not significant. The results of these tests may provide guideline for evaluation of dynamic characteristics and reinforcement design of Heavy Haul Railway subgrade.