EFFECT OF IMPROVEMENT RANGE OF STATIC SAND COMPACTION PILE METHOD FOR LIQUEFACTION MITIGATION ON HORIZONTAL RESISTANCE OF PILES

The static compaction sand pile method is a method of increasing liquefaction resistance by compaction of the ground through low-noise and low-vibration construction of sand piles using static press-in force. In this paper, based on a case study of a pile-foundation building, the effect of the narrowing of the improvement area on the stresses generated by the piles was investigated by static incremental analysis using a beamspring model that takes into account the linearity of the soil and pile materials. The analysis was performed by using the earthquake response analysis to obtain the ground displacement and horizontal pile head force, and then using the shape and pile layout of the building, and the location of the area to be improved by the static compaction sand pile method as the parameters. The results of these analyses showed that when the area of improvement is reduced, the horizontal forces are concentrated in the improved area, which requires attention to secure the shear strength of the pile, but the influence on the bending moment is relatively small, and the load on the unimproved area tends to be reduced compared to that of the fully improved area.