Modelling liquefaction of soils with LS-DYNA using a SANISAND-based material model

Saturated sandy soils can be prone to liquefaction during earthquakes: the soil loses strength and stiffness due to cyclic shear loading, becoming more like a liquid or quicksand. When liquefaction occurs, structures founded on such soils may experience severe damage or large settlement, or may even overturn. Designers of structures in seismically-active regions where liquefiable soils are present need to assess the likelihood of liquefaction occurring under design-level earthquakes and, if required, provide mitigating measures in the design. Three-dimensional nonlinear finite element analysis can be used to understand the effects of liquefaction on a structure and, if sufficient validation of the soil properties has been carried out under a range of stress conditions, can potentially predict the extent of liquefaction that will occur as a result of a given earthquake time-history. However, this requires a soil material model capable of reproducing the phenomena relevant to liquefaction.