中文摘要：

针对武广高速铁路无碴轨道路基的长期动力稳定问题,应用共振柱仪对沿线石灰岩类红黏土进行了动剪模量和阻尼比的试验研究,得到了Gd/Gdmax～γdandλ～γd关系曲线,给出了红黏土的Davidenkov模型参数、阻尼比经验公式及其相应的拟合参数。动剪模量随动剪应变的增大非线性减小,阻尼比随动剪应变的增大非线性增大。围压对动剪模量及阻尼比的影响规律因动剪应变水平的不同而不同：低剪应变水平下,动剪模量随围压的增大而增大,阻尼比随围压的增大而减小;高剪应变水平下,动剪模量随围压的增大而减小,阻尼比随围压的增大而增大。对比分析表明：红黏土动剪模量大于一般黏性土动剪模量平均值,阻尼比大于砂土阻尼比平均值。研究成果为红黏土路基动力稳定性评价提供动力参数,也为红黏土动力特性的深入研究提供基础。

英文摘要：

In view of long-term dynamic stability of roadbed under ballastless track of Wuhan-Guangzhou high-speed railway,dynamic shear modulus and damping ratio of red clay were studied by free vibration column test.The relationship curves of Gd/Gdmax～γd and λ～γd of red clay were obtained,the model parameters of Davidenkov and empirical formula of damping ratio and it＇s fitting parameters of red clay were also given.Dynamic shear module reduces and damping ratio increases nonlinearly with the accretion of dynamic shear strain level.Under low shear strain level,dynamic shear module increases and damping ratio reduces with the augment of confining pressure.Under high shear strain level,dynamic shear module reduces and damping ratio increases with the increases of confining pressure.The contrast analysis shows that dynamic shear modulus of red clay is bigger than mean value of it of cohesive soil,and the damping ratio is bigger than average of it of sand soil.Results in this paper will offer precious reference for further study on dynamic characteristic of red clay.