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This paper presents the numerical solutions for consolidation of the under-consolidation dredger fills. By a field test the delivery rules of negative vacuum pressure in the PVDs are studied, the relationship between permeability and effective stress of the high water content soil is also studied by an experiment, then a plain strain FEM program was coded for the dredger fills consolidation analysis in which the nonlinearity constitutive relation Duncan-Chang's model is employed into the Biot's consolidation theory, and the nonlinear permeability law is also employed in the Biot's consolidation theory. As an under-consolidated soil, the self weight that is not consolidate before the enforcement and negative vacuum pressure is included as the consolidation load in this paper. At last, two project cases were calculated using this program, the result shows that the program is suitable to analyzing the under-consolidated soil consolidation under vacuum preloading or surcharge preloading method.

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Tolerably mobile subsea foundations may be used to replace conventional fixed mudmat foundations for pipeline infrastructure and are designed to slide on the seabed along with the connected pipeline, in order to accommodate thermally induced horizontal forces. This allows the size of the foundation and the resulting fabrication and installation costs to be substantially reduced. The performance of mobile foundations is explored in this paper through four centrifuge model tests on a NC or LOC reconstituted calcareous silt obtained from the Northwest Shelf of Western Australia. The results are compared to three existing tests performed on a kaolin clay. The results show that under typical periodic surface sliding and intervening rests, sliding resistance evolves within a cycle with resistance peaks evident at either end of the sliding footprint due to the formation of berms, and the residual resistance increasing with sliding cycles towards a drained state. Shear and consolidation induced settlements accumulate with sliding cycles although at a reducing rate. The tests in the calcareous silt show higher normalised initial peak sliding resistance, a more dramatic loss and slower recovery of sliding resistance with cycles, and slower rate of decrease of incremental settlement compared with the response in kaolin clay.