Dynamic Behavior Of Soft Clay Under Intermittent Cyclic Load

After long-term traffic loading,large settlement occurs in pavement engineering constructed on soft clay subgrade.In most of the previous research,traffic loading was simulated by imposing cyclic loading in the vertical direction with a semi-sine compression wave,which is purely consecutive without intervals.However,traffic loads,especially plane loads,are not consecutively imposed on the ground,i.e.,there are intervals between adjacent cyclic loads.For example,the interval time between taking off and landing of airplanes is much larger than the time period in which the plane load could affect the runway.In order to predict the settlement accurately,the intervals between cyclic loads should be considered.In this study,a series of one-way cyclic triaxial tests with constant confining stress and intermittent deviatoric stress through self-defined intermittent waveforms under drained conditions were conducted to investigate the dynamic behavior of soft clay.The permanent axial strain,stress-strain hysteretic loops,resilient modulus,volumetric strain and permanent axial strain generated in one cycle were analysed under different interval ratio of waveforms and CSRs.The results showed that the interval ratio of waveform had an influence on permanent axial strain,stress-strain hysteretic loops,resilient modulus,volumetric strain and permanent axial strain generated in one cycle,which depend on the degree of CSR and was influenced by drained an undrained condition.These conclusions provides good supplements for the experimental studies of behavior of soft clay under traffic loading,which are of guiding value for the design of traffic engineering.