Numerical Analysis Of Consolidation Characters Of Composite Ground Under Road Embankment

Composite ground is being used abroad in recent years in treating the soft-ground under express highway, research about each kind of composite ground in academic circles are more and more,But at present contrast research were still very few.This paper analyses many problems about consolidation characters of composite ground under embankment,and concludes their deformation rules, based on unit cell model and plane deformation model, using finite element software of PLAXIS. All the work done is as follows:1. Analyze the reason why composite ground which reinforced by cement-mixed piles when they are fully penetrated consolidate more quick than uniform soil ground separately from vertical and radial direction pore pressure and its gradient,The analysis indicated that pore pressure gradient increased in composite ground deep level is the main reason why it consolidate more quick.2. Contrast research the consolidation characters of composite ground which reinforced by piles when they are partially penetrated and fully penetrated.Composite ground with floating piles is different with composite ground with end bearing piles,it consolidate more slow than uniform soil ground, the reason is that the additional stress increased in composite ground deep level,caused its pore pressure dissipates more slow.3. Contrast research the distribution rule of pore pressure and its gradient in composite ground which reinforced by strong draining piles and weak draining piles. The computation indicated that the pore water's main flow direction in strong draining piles is radial, the pore water mainly flow from the soil to the pile; The pore water's main flow direction in weak draining piles is vertical, the pore water mainly flow from the pile to the soil.4. Contrast research using the unit cell model and the plane deformation model. The computation indicated that the plane deformation model can reflect the ground's whole deformation situation that the settlement in middle of road is large than the settlement of roadside,the finally settlement of its piles smaller than the unit cell model,and it consolidate more quick than the unit cell model.