Abstract: The basic features of the mud surface settlement and the sedimentation rate under the deadweight in heterogeneous dredger fill soil with initial varying sand-mud ratio and initial water content are acquired by means of large size settlement column tests, and the variation of the density profile of the sample is obtained by combining with stratified sampling method. The results show that: heterogeneous dredger fill soil and particles settlement under deposited deadweight have a closer relationship with the initial moisture and sand contents; the higher initial water content, the greater the settlement, the faster the settlement rate; the more sand, the greater settlement. The settlement increase significantly as the sand-mud ratio grows, but the settlement declines as the sand-mud ratio increases when sand-mud ratio is more than 20%; and the lower the initial moisture content, the more obvious the phenomenon. At higher initial moisture content, the settlement-time curve of each sample can be basically divided into three stages; and nonlinear characteristics are obvious in the stage II. As the initial moisture content declines, the three stages and nonlinear characteristic in the settlement - time curve gradually disappear; the lower sand-mud ratio, the more significant linear characteristic in settlement-time curves. Density profile along the height changes a lot at the high moisture content and high sand-mud ratio; and it presents a step-change feature; while it gradually varies linearly as the initial moisture content and the sand-mud ratio declines. Initial moisture content and the sand-mud ratio effect the grain distribution, higher the initial moisture content and the sand-mud ratio is beneficial to (>0.075 mm) sedimentation of particle size greater than 0.075 mm; the higher the sand-mud ratio, the more particle size less than 0.005 mm at the bottom, which shows the feature of group settlement.

Key words: heterogeneous dredged fill, mud surface settlement, sedimentation rate, sand-mud ratio, density profile