Abstract: In the evaluation of degree of compaction of soils surrounding piles, the unit weight testing method usually varies with different backfill materials. The sand cone method is usually applied in various soil materials, the cuttingring method is not usually applicable to loose granular materials. When the target soil is suitable for both testing methods, the comparative testing using both methods is conducted and the advantages as well as disadvantages of each testing method are summarized so that the most appropriate test method can be applied in the site specific conditions and soils.

Key words: sand cone method, cutting-ring method, degree of compaction