Abstract: For the silty fine sands of 3 to 5 m thickness justly formed by dredging at the material yard of a bulk cargo wharf, based on the instrumented monitoring results of a testing area improved by vibro-compaction without additional backfill materials and trace inspection in the project, the change of excess pore water pressure and range of validity of vibroflotation is analyzed. The strengths are compared before and after vibroflotation. The design parameters, construction techniques and quality control method of vibro-compaction are proposed for the large-scale practice. In the first inspection, the problem of local poor compaction inside the vibroflotation column is found; the resulting reasons are analyzed and resolving measures are put forward. The final inspection results of large-scale practice indicate that the proposed parameters are feasible; the quality of improving ground satisfies the design requirements. The testing and application of this project indicates that vibro-compaction method without additional backfill materials for silty fine sands can be used for large-scale practice after the scientific testing methods quality tracking and solving measures of defects carried out.

Key words: vibro-compaction without additional backfill materials, dredging, silty fine sands, ground treatment