ELEMENT ANALYSYS OF CONSOLIDATION OF SOIL UNDER SURCHARGE AND VACUUM PRELOADING

As an under-consolidated soil, the reclaimed soil consolidation with vacuum preloading is very complex, so are the boundary and initial conditions. Through the analysis of the formation of the reclaimed soil foundation and its consolidation process, the initial pore pressure and the delivery of negative vacuum pressure in the PVDs herein were studied. The negative vacuum pressure was applied in the sand layer and the PVDs elements. The nonlinearity constitutive relation (Duncan-Chang's model) was employed into the Biot's consolidation theory, and a plain strain FEM program was coded considering different load conditions, initial conditions and boundary conditions. The behavior of the soft clay consolidation was also analyzed with the program. The surcharge was put into effect in the program. As a result, the program can be used to analyze the reclaimed soil consolidation with pure vacuum preloading method and also vacuum combined with surcharge preloading method. Comparing the calculating results with the observed data, it is confirmed that the developing trend of settlement and pore pressure agree very well with the field result.