Taking a large oil tank foundation project of Yangzi petrochemical company for example,we conduct an experimental study on dynamic consolidation of the filled fly ash underlying silty soft soil.At first,the surface settlement around craters and pore water pressure are inspected,and then the improving effects are detected through laboratory soil mechanics test,load plate test,standard penetration test,cone penetration test,etc.The test shows that it is obvious to improve the foundation with construction technology of low energy in the beginning and gradually growing energy and cycles combined with gravel cushion,vertical plastic drainage board and the layout of cinquefoil for tamping point.The mechanical property and anti-deformation characteristics are improved obviously and the liquefaction problem of the upper fly ash is eliminated.The whole consolidation effect is remarkable, and physical-mechanical properties are better than the expected.At the same time,the optimal parameters and construction techniques are obtained by analyzing the measuring data.