Abstract: With regard to the case of silt ground disposal project of Guangzhou Nansha Taishan petrifaction storage area，based on microstructure tests laboratory soil test and the in—situ tests including the load experiment，the dynamic penetration test and vane shear test，the micro-structural effect and mechanical properties of SDDCM ’Streatment of saturated soft clay are investigated from macro and micro levels．As a result，the evolution mechanism of the constru ction process is revealed，and the reinforcement effect is evaluated．The research results reveal that with the new construction technology of“static-dynamic combing，the tamping is light first and then becomes weightier and weightier with energy gradually added，fewer times and more cycles” with pre—compression by soil load and reticulation drain，the improvement effects of SDDCM on the large area of deep and thick silt foundation are remarkable，physical—mechanical properties are improved obviously，and physical—mechanical properties are better than expected．SDDCM has extensive prospects for engineering applications．

Key words: static-dynamic drainage consolidation method(SDDCM)；sih foundation；mierostrueture；in-situ test；reinforcement effect