A Numerical Study on Artificial Fill Embankment with Liquefiable Foundation Using FLAC

The problem of seismic liquefaction related to artificial fill embankment is complicated. In this study, by making using of Finn model, a typical artificial fill embankment was simulated by means of Finn model in FLAC. Numerical simulation results indicated that the pore water pressure of saturated sand soil increased extremely which resulted in the significant decrease of the effective stress. When the effective stress decreased approximately to zero, the liquefaction phenomena occurred. According to the change of pore water pressure at different locations and depths, three rules have been obtained. Firstly, the occurrence time for the first peak of pore water pressure coincided with the seismic peak acceleration of input wave. Secondly, the liquefaction occurred earlier in the upper layer of saturated sand soil than in the lower layer below the bottom of slope. However the duration of liquefaction in the lower layer of saturated sand soil was longer than in the upper layer. Thirdly, the upper layer of saturated sand soil was almost not liquefiable below the top of slope, while the lower layer was easily liquefiable with long duration time. In summary, the characteristics of seismic liquefaction in the artificial fill embankment were closely related to the seismic wave, locations and depths of saturated sand soil in a slope.