Abstract
The present study investigated and elucidated the liquefaction characteristics of sand-clay layered ground under combined earthquake motions by performing a series of shaking table tests. The design concept for sand compaction pile as liquefaction countermeasures was also re-evaluated, and it is shown that the influences of both increase in relative densities and lateral stresses due to the compaction can be assessed uniquely by the relationship between the N-value and the liquefaction resistance. On the basis of these results, the application of the SCP to the sand-clay layered ground is found to work effectively in light of the three distinct mechanisms involving densification, stress enhancement, and partial drainage through the sand pile penetrating the clay layer. These findings are important for the rational liquefaction assessment and its countermeasures of sand-clay layered ground.
