Abstract: A series of experiments of high energy dynamic compaction(HEDC) with 8000,10000,15000 kN·m are conducted on rubble fill sites underlain by thin soft clay layers in coastal areas and in mountain valleys,respectively.The results of cone dynamic penetration test(DPT) and plate loading test(PLT) for several sites are systematically analyzed and compared with those before HEDC.Some conclusions concerning the effective depth of improvement(EDI) on the rubble fill sites in mountain valleys or those underlain by thin soft layers in coastal areas under various HEDC are drawn.It is recommended that the EDI should be pre-estimated by the revised Menard Formulation,with the revised coefficient within 0.29～0.40.Especially,the low value should be used under the condition of the thin soft strata and shallow groundwater levels.