Researching Of Settlement Calculation For Bonding Material Pile Composite Foundation Under Loads Of Embankment In Stratified Soil

Along with our country’s infrastructure construction such as highway, high-speedrailway and City Metro’s rapid development, the composite foundation under flexiblefoundation such as embankment has been widely used, and achieved good economicbenefits for the production of people’s lives a great convenience. But the theoryresearch of composite foundation under flexible foundation still lags far behind theengineering practice, and the settlement of composite foundation under loads ofembankment and the settlement of composite foundation under rigid foundation arenot the same. Practice shows that the composite foundation settlement of the rigidfoundation,the basis of calculation theory used for flexible composition foundation,such as embankment, the proceeds of the settlement calculated and measured valuesquite different, and is unsafe. As the flexible foundation, the settlement of compositefoundation under flexible foundation such as embankment based on free strainconditions, many scholars at home and abroad have made relevant research. Theresearch are basically based on the surrounding soil homogeneous ideal assumption.But the actual situation of the soil between piles are stratified, and properties of thelayers of the soil are very different, especially the difference of the modulus ofelasticity will cause the difference of results of settlement in reinforced region ofcomposite foundation.As there was no relative slippage at the interface of piles, based on Alamgir’spile-soil displacement pattern, a new method of calculating the settlement inreinforced region of bonding material pile composite foundation considering norelative slippage between piles and soil in stratified foundation was developed, andanalytical formulas of compressive quantity for piles and surrounding soil inreinforced region of composite foundation under embankment loads were derived,along with the expressions for vertical stress of pile and surrounding soil, andshearing stress of pile surrounding in each soil layer, by applying elasticity,compatibility of pile-soil displacement and boundary conditions.As there was relative slippage at the interface of piles, based on the research ofthe front part, assumpt that the pile top cunsion and pile bottom layer with Winklerfoundation model in consideration of both upward and downward penetrationdisplacements of piles, and a new method of calculating the settlement in reinforced region of bonding material pile composite foundation considering the relativeslippage between piles and soil in stratified foundation was developed.Linear elastic single pile composite foundation model was derived by ANSYS2D, the results show that the neutral point of pile is insensitive to the variance ofelastic modulus of surrounding soil, while the elastic modulus of the underlying soilhas great influence on the neutral point of pile. And group piles composite foundationmodel was developed also by ANSYS2D based on specific project.Two practical engineering calculation were compared with finite elementanalysis and other methods and the measured results, the results show that theestablished settlement calculation method of bonding material pile compositefoundation under embankment loads in stratified foundation was reasonable andfeasible.