Abstract: To analyze the dynamic characteristics of silty clay in Xiongan New Area, a GDS multifunctional dynamic cyclic triaxial testing system was used to conduct dynamic triaxial tests on the silty clay under 14 working conditions (different confining pressures, consolidation ratios and loading frequencies). The variation rules and relative parameters of dynamic backbone curves, dynamic elastic modulus, dynamic shear modulus and damping ratio under different working conditions were analyzed in depth. The experiment results indicate that: with the increase of dynamic stress amplitude, the dynamic strain shows a nonlinear growth and exists a certain critical dynamic stress value. With the increase of dynamic strain, the dynamic modulus decreases gradually, and the rate of decrease is first fast, then slow, and finally tends to stabilize. As the dynamic shear strain increases, the damping ratio shows nonlinear growth, and the maximum damping ratio does not exceed 0.12. With the increase of confining pressure and consolidation ratio, both the dynamic strength and dynamic modulus increase obviously. The confining pressure and consolidation ratio have little influence on damping ratio and have the characteristics of normalization. As the frequency increases, the dynamic stress amplitude and dynamic elastic modulus increase, but the increase is not significant. Through comprehensive analysis of the influence of three variables on the dynamic characteristics of silty clay in Xiongan New Area, it is concluded that confining pressure has the greatest impact, followed by consolidation ratio and loading frequency.

Key words: geotechnical engineering; silty clay; dynamic triaxial test; dynamic elastic modulus; dynamic shear modulus; damping ratio

摘要： 为分析雄安新区粉质黏土的动力特性，采用GDS多功能动态循环三轴试验系统，对雄安新区粉质黏土进行14种工况（不同围压、固结比和加载频率）下的动三轴试验，深入分析了动骨干曲线、动弹性模量、动剪切模量、阻尼比等在不同工况下的变化规律及相关参数。试验结果表明：随动应力幅值的增大，动应变呈非线性增长,且存在某一临界动应力值；随动应变的增大，动模量逐渐减小，且减小速率先快后慢、最后趋于稳定；随动剪应变增长，阻尼比呈非线性增长，且阻尼比最大值不超过0.12；随围压与固结比增大，动强度和动模量均明显增大；围压与固结比对阻尼比影响较小，具有归一性特征；随频率增大，动应力幅值、动弹性模量增大，但增长幅度并不明显。综合分析三变量对雄安新区粉质黏土动力特性的影响程度得出：围压影响最大、固结比次之、加载频率最小。

关键词: 岩土工程；粉质黏土；动三轴试验；动弹性模量；动剪切模量；阻尼比