Development and improvement effectiveness of sand compaction pile method as a countermeasure against liquefaction

The sand compaction pile (SCP) method was developed in Japan to improve soft grounds. One of the major features of the SCP method is that it can be applied to all soil types found in Japan, from sandy to clayey soils; and therefore, it has been widely used for the improvement of soft grounds. Recently, the SCP method has been mainly adopted as a countermeasure against liquefaction, and its effectiveness in preventing liquefaction has been confirmed through past large earthquakes. This paper provides an outline of the conventional SCP method, including its principle, history, equipment, and implementation, and also describes other methods derived from the SCP method as liquefaction countermeasures. Furthermore, several examples are reported to confirm the effectiveness of the methods through past large earthquakes.