Exploring the Onset of Liquefaction of Saturated Loose Sand Under Monotonic and Cyclic Loading Using DEM

This paper investigates the onset of liquefaction of saturated loose sand under various loading conditions, including monotonic load, cyclic load with strain control and cyclic load with stress control. The undrained tests are conducted under a constant volume. The macroscopic and microscopic behaviours are analyzed based on the available data. Temporary liquefaction is observed for the monotonic loaded sample. For cyclic loaded sample with strain control, the amplitude of deviator stress declines and finally tends to be zero after 11 cycles, while the amplitude of deviator stress is sustained until 9th cycle for cyclic loaded sample with stress control. The redundancy index is found to be applicable for both monotonic and cyclic loaded samples in monitoring the onset of liquefaction.