关键词: 交通工程, 软土, 循环荷载, 动三轴试验, 累积塑性应变模型, 动应力, 静偏应力, 临界动应力

Abstract:

To evaluate the influence factors of cumulative plastic strain of saturated soft clay, the cyclic triaxial tests with stress-controlled are conducted to investigate the behaviors of soft clay subjected to cyclic loading. The research results include four aspects. Firstly, there are three types of cumulative plastic strain of saturated soft clay under cyclic loading, such as stable type, destructive type and critical type. Cumulative plastic strain of saturated soft clay increases with repeated load when dynamic stress is less than the critical dynamic stress. But the increasing rate slows down until it trends to a stable value. On the contrary, the strain increases quickly with repeated load until clay is destructive. Secondly, a new mathematical function, containing three parameters, is suggested to fit the curve of cumulative plastic strain of saturated soft clay versus repeated load under cyclic loading. The influence laws between parameters and dynamic stress are analyzed. Thirdly, based on the influence laws, a method for confirming the dynamic stress without static deviator stress is put forward. Finally, an empirical equation for cumulative plastic strain which derived from the mathematical function, containing dynamic stress, confining pressure, static deviator stress and repeated load is synthesized.

Key words: traffic engineering, soft clay, cyclic loading, dynamic triaxial test, cumulative plastic strain model, dynamic stress, static deviator stress, critical dynamic stress