vacuum loading mode are generally not considered in Traditional vacuum preloading method in the reinforcement of soft soil. This paper carried out indoor model test

it tested four groups of the flow mud soil samples the water content of which is 100%

the vacuum loading mode are -80 kPa

-60 kPa→80 kPa

-40 kPa→-80 kPa

-20 kPa→-80 kPa

Water

settlement and lateral deformation was monitored during the loading of the sample in the course of the test

and changes of the water content

plasticity index and vane strength was studied after the test. The test results showed that: (1) Vacuum loading mode significantly effects on consolidation of dredger fill flow mud. (2) Soil settlement is largest and strength is highest when the initial vacuum value of -20 kPa better than the others; soil settlement is smallest

and strength is lowest when the initial vacuum value of -80 kPa better than the others. (3) From the distribution characteristics of the plasticity index

soil particles move with water in the soil discharge

initial vacuum load value larger this trend is more obvious; the part of the soil particles will accumulate around of plastic vertical drain and so as to reduce soil permeability; severe cases will affect soil consolidation of follow-up. Finally

it is recommended that a lower initial load mode to loading in the flow mud vacuum consolidation process.