Sand Compaction Pile Method Utilizing Recycled Materials

The Sand Compaction Pile (SCP) method is a technique of constructing well-compacted sand piles in the ground by repeatedly penetrating casing pipe with infilling material, pulling them out, and re-driving them into the ground. Sand and gravel are usually used as the infilling material for this SCP method, but even for liquefaction countermeasures, materials with the fines content of 5–15% are generally used. However, in recent years, it has become difficult to secure good quality materials (especially natural sand materials) that satisfy these conditions, and the use of recycled materials (recycled crushed stone and slag) has increased. This paper describes the history and transition of the use of SCP infilling materials as recycled materials and introduces a model test (shaking table test) conducted using infilling materials with some amount of fines and an actual case study (field test) of using recycled materials, and discusses the results of the tests.