Research On Consolidation Settlement For Foundation Of High Filled Expressway Near Yangtze River

Construction of high-fill embankments on highways is a common type of construction.When it is built on a foundation soil with high compressibility and high water content,it produces large deformation.The selection of foundation soil parameters has a great influence on the calculation of foundation deformation.Based on the research background of the foundation of K13 + 206.6 in Wuhu Street section of Wuhan Jiangbei Expressway,this thesis focuses on the selection of physical and mechanical parameters of the foundation soil,calculating the foundation consolidation settlement and analyzing the influence of the foundation soil parameters on the foundation consolidation settlement.The following research work is completed in this thesis:(1)Based on the ground survey report,combined with relevant specifications,and considering the compactness of the soil,the physical and mechanical index properties of the natural foundation and composite foundation(reinforced area)soil were analyzed,then appropriate parameters were determined.(2)Using the nonlinear Finite Element software,a two-dimensional finite element model of foundation consolidation was established,and then the settlement of Foundation surface and Subgrade was further calculated.Comparing and analyzing with the on-site monitoring,the result shows that the consolidation parameters of composite foundation and natural foundation determined in this paper were reasonable.On this basis,this paper also analyzed the settlement at the surface of the foundation under the action of fill and its equivalent load,shows that the consolidation settlement of the foundation surface under the assumption of the two models is closer.(3)The conventional design method was used to calculate the final settlement of the foundation.Selecting the compression modulus in the geological survey report and the compression modulus considering the compactness of the soil,the settlement under two compression modes was analyzed,and the results show that the using compression modulus considering compaction to calculate foundation settlement is closer to the actual situation.The result explains that the standard method for calculating foundation settlement needs to reasonable consider the soil compaction.(4)Using the equivalent load action model on the surface of the foundation,the parametric analysis of the consolidation settlement of the foundation was carried out to investigate the influence of the Poisson’s ratio,permeability coefficient of the 2C soil layer in the composite foundation reinforced zone on the foundation settlement.Also the influence of Poisson ratio,permeability coefficient and deformation modulus of the 3S,3CM,5CM on the consolidation settlement of the non-reinforced foundation was analyzed.The results show that the parameters of the reinforced zone and the non-reinforced zone both significantly infiuence the consolidation settlement.The larger the permeability coefficient,the faster the consolidation time will be and the greater the modulus,the smaller the settlement will be.The research results of this paper can provide a certain reference for the settlement analysis and foundation treatment of high-compressibility foundations along the Yangtze River.