Analysis Of Deformation Influence Factor And Settlement Prediction On Soft Soil Subgrade

The problem, how to solve deformation stability and settlement on soft soil subgradeafter construction during fill period, has always been the hotspot and difficult matter oftechnology in geotechnical engineering. Based on the coastal expressway engineering inHebei province, the deformation influence factors during fill period and long-term stabilitydeformation prediction on soft soil subgrade are studied penetratingly, combinedmeasured data analysis theoretical formula deduction with numerical simulationcalculation. The research contents have some theoretical meaning and engineeringreference value on subgrade stability analysis, informational construction guidance.Firstly, the simplified calculation method for numerical modeling of sand-drainedground has been studied. After Chen Lihong Equivalent Sand-wall Theory formulationsare deduced and analyzed, an equivalent modeling method that adjusts sand-wall thicknesshas been put forward, which is used for FEA model construction and whose feasibility hasbeen verified by contrast and calculation. Secondly, according to the equivalent modelingmethod that adjusts sand-wall thickness, the numerical simulation calculation is applied insoft soil subgrade deformation using the PLAXIS, considering that the plastic drain boardis used or not. And the failure evolution mechanism of subgrade stability has been studiedon the soil relative shear strength, displacement increment, plastic zones development andother aspects. Then the influence rules of deformation characteristic on soft soil subgradeare found, involving height of embankment, mild clay laminated, geogrid and plasticsdrain board.Finally, based on grey model and gompertz model, a new combined prediction modelhas been built using optimal weighted combination principle. The prediction accuracy ofnew model has improved, compared with the former by the field data testing. Thedeformation prediction model is applied in later evaluation of foundation treatmentmethods, and the good result is obtained.