On the deep soil mixing method in the mitigation of liquefaction-induced bearing capacity degradation of shallow foundations

Bearing capacity degradation in shallow foundations due to subsoil liquefaction is not a new challenge in earthquake geotechnical engineering. Thus far, limited mitigation measures against this problem were suggested in the literature. In this paper, mitigation of liquefaction-induced bearing capacity degradation of shallow foundations using Deep Soil Mixing (DSM) method was investigated numerically. A 3D finite difference model has been developed via FLAC3D. It was explored whether liquefaction effects on static and seismic bearing capacity of shallow foundations were diminished, and may be effectively overlooked, for DSM column diameter and length and also shallow foundation width variation. It was found that an artificial non-liquefiable soil layer made by DSM method improves the seismic bearing capacity of shallow foundations remarkably. Therefore, in terms of excess pore water pressure generation decreases and bearing capacity ratio increases. It was also concluded that by increasing the diameter and length of the DSM columns, the seismic bearing capacity of shallow foundations increases. However, as shallow foundation width increases, along with an increase in DSM column diameter and length, the performance of DSM columns and accordingly shallow foundation decreases.