Nonlinear Analysis Of Settlement Calculation Of Pile Foundation In Layered Soil

Pile fo undation is one of the widely used types of foundation in the fie ld of c ivilengineering, and settle ment calculatio n of pile foundation has been one of the mostdiffic ult and hot issues. In recent years, because layered and no nlinear characteristicsof so il can be considered in the calculation of pile settle me nt, the load transfer methodhas been widely used. Selection o f load trans fer model has a major impact on pilesettle ment calculatio ns. However, when a curve model was used to describe the shaftresistance of pile, the basic differentia l equations is hard to solve. Additiona lly, theexisting load transfer model d id not cons ider initia l critical frictio n on pile-soilinterface.To solve the proble m above, firstly an overview of the p ile foundation ispresented. Research status of the pile settle me nt calc ulation under vertical loads isdiscussed in depth and a variety o f settle ment ca lculation method are summarized.The process and mechanis m o f load transfer of p iles is e xplored, and focus on thecomparative a nalys is o f friction type piles and end bearing p iles. Based on that, therule of load transfer cha nging with re leva nt factors is ge neralized. Then, start withstrain, stress, and constitutive relatio ns of the ideal e lastomer, the genera l equationsof elastic ity is established. By s imp lifying it, the basic differentia l equations of loadtransfer method is got. A ideal e lastoplastic model and a hyperbola model were usedto describe the sha ft resistance and the end resistance of a pile respectively. Withthese models, settle ment of a pile in la yered soil is analyzed and calculated. Andformulas to solve the load-settle ment curve are obtained and MATLAB codes arewritte n based on them. Lastly, the p ile is divided into segments a nd the axia l force ofeach segme nt is assumed to remain unc hanged. So, a spring model o f p ile-soilinteraction s ystem under vertical loads is created. Because there is no need to analys isthe differentia l unit o f piles in the model, ordinary d iffere ntia l equatio ns aresimp lified as algebraic equations.Based on the existing s hear test results of soil structure interface, deformationcharacteristics of p ile-soil interface is analyzed and a load trans fer hyperbolic modelcons idering affect of initia l critica l friction res istance on pile-soil interface isestablis hed. The n, load-settle ment calculatio n formula is derived fro m perspective ofmecha nics with consideration of initia l critical friction resistance, so il stratification and nonlinear characteristics. Three parameters of the load trans fer hyperbolic modelcons idering affect of initia l critica l frictio n resistance whic h would have a greatimpact on settle ment are analyzed. The calculated load settle ment curves consideringinitia l critica l friction resista nce agree well with the measured curves and agree betterthan calc ulated curves without cons idering initia l critical friction res istance inanalyzing two engineering exa mple.