This paper reports a case study on treatment of soft days by dynamic compaction. A special technique adopted in this project allowed massive stiff columns to be formed under the impact locations, and the soils between these impact locations to be replaced and mixed with granular fills, hence creating a composite foundation. The comprehensive field investigation showed that the allowable bearing capacity of the treated ground (as a composite foundation) was 350 kPa, a significant increase compared with that of untreated ground (70 kPa). The achieved stiffness modulus of the composite foundation was 24 MPa
