Abstract:
The model tests on hydraulic-dredged slurry with initial moisture content
w0 of 200%~2000% in Tianjin Binhai District after sedimentation of 100 days are performed to investigate the self-weight sedimentation and consolidation characteristics. The relevant indices for the hydraulic fill are suggested so as to provide reliable theoretical support for dredger filling projects at the design and construction stages. The results show that the settling of the hydraulic-dredged slurry in Tianjin includes two types, deposition settling and consolidation settling, respectively. The former undergoes flocculation, hindering settling and consolidation. The critical moisture content
w0* is 400%, and there is a linear relationship between
w0* and the liquid limit. When
w0≤
w0*, the consolidation settling occurs, and the settlement can be calculated by using the one-dimensional consolidation theory. When
w0>
w0*, the deposition settling occurs, and the settlement can be calculated by using the sedimentation rule. The void ratio of soil formation
e0* is 10.92. The time of sedimentation stability can be calculated using
Tc=159(
w0/ wL)
-1. The void ratio of sedimentation stability can be calculated by the piecewise formulae
ec=0.08+5.4(
e0≥13.65)and
ec=0.4+1.03(
e0<13.65). The flocculation yield stress
Ps is 0.3 kPa and the boundary void ratio
es is 6.4. The self-weight sedimentation and consolidation is the process that the flocculation yield stress and the effective stress influence each other, so that different settlement characteristics are aroused. The micro-structure of dredged mud in parallel direction to sedimentation is flocculation structure, and that in vertical direction to sedimentation is a stacked one.