The structure of the seabed silty soil in the Yellow River delta is understood by its properties and piping phenomena under cyclic loads. Applying breakage mechanics

a double-medium model composed of structural lumps and structural bands is established. During the process of increase loads

decrease loads and liquefaction seepage

deformation and breakage in the structural bands and exchange of effective stress and pore water pressure are qualitatively researched. Qualitative analysis indicates that the strength of consolidation should be increased within the depth of liquefaction

which accords with the result of test. Experiment shows that the different phenomena of liquefaction seepage are regarded as cause of existing piping in structural bands and water discharge in structural lumps with the double-medium modeling.