Abstract: The deformation characteristics of typical saturated silty clay under long-term traffic load in Jiaozuo area were investigated through dynamic triaxial tests on single undisturbed specimen under multistage loading and parallel specimens under constant amplitude of loading. By analyzing the strain-vibration curve and dynamic stress-strain hysteretic curves, the influences of dynamic stress, confining pressure, consolidation mode, and vibration frequency on soil deformation were examined. The following conclusions were obtained: the development mode of dynamic strain of typical silty clay in Jiaozuo can be mostly summarized as steady mode and destructive mode—dynamic strain grew steadily at a certain stress level and developed to failure when that stress level was exceeded—rather than critical mode. The strength of single soil specimen intensified under step-by-step loading, and the dynamic stress level required to result in failure increased correspondingly. As for multiple specimens under constant amplitude of loading, the deformation surged until failure happened even in the presence of low vibration frequency when dynamic stress exceeded a critical value. In addition, the increment of confining pressure and consolidation ratio could also raise the soil strength, with less recoverable elastic deformation. When vibration frequency was smaller or larger than a critical value, the deformation of soil both increased.

Key words: silty clay, deformation, traffic load, dynamic triaxial test, consolidation ratio, vibration frequency, hysteretic curve