Abstract: This trial compaction area for a typical silty fine sand layer site of a project in Guangdong is presented as a case history in this paper. After three times of the dynamic compaction using the 5 000 kN·m energy level in A1 trial compaction area, the site soil was tested, analyzed, and evaluated by using the static plate load test, the standard penetration test and the cone penetration test. The results show that: (1) Compared with before the dynamic compaction, the effect of the soil improvement after the compaction is obvious; (2) The effective improvement depth of the silty fine sand layer is about 7 to 9 meters; (3) Both the standard penetration test and the cone penetration test can evaluate the compaction effect of the foundations soils after the dynamic compaction improvement. The results of the two types of tests are close to each other; (4) It is determined that the site liquefaction potential is eliminated after the dynamic compaction through the blow counts of the standard penetration test in A1 trial compaction area.

Key words: Dynamic Compaction, Trial Compaction Area, Foundation Soil Testing, Silty Fine Sand Layer, Effective Improvement Depth