STUDY ON UNLOADING REBOUND DEFORMATION OF DREDGER FILL WITH CENTRIFUGE MODELING TEST

Dredger fill is characterized with unloading deformation. Unloading deformation of dredger fill is studied with a centrifuge model test. The test results show that the curve of average deformation vs. load is linear;the curve of average deformation and loading-time is hyperbola,and there are two critical unloading ratios in unloading deformation,which is 0.4 and 0.9 respectively. When the critical unloading ratio is less than 0.4,the increment of pore ratio is very slow,and the pore ratio increases with increasing of unloading ratio. When the critical unloading ratio reaches 0.6,the pore ratio linearly increases with increasing of unloading ratio. However,when the critical unloading ratio reaches 0.9,the pore ratio does not increase with the increase of unloading ratio. An empirical formulation is determined through fitting to describe the relationship between pore ratio and unloading ratio. The formula can be used to predict the unloading deformation of dredger fill.