Study On Differential Settlement Of Composite Pile Foundation With Long And Short Piles

In the current pile foundation design methods,the control of the basic differential settlement is often neglected.Therefore,there are different degrees of differential settlement in the foundation,and the occurrence of differential settlement will cause undesirable phenomena such as deformation and instability of the superstructure.In recent years,the research on the differential settlement problem in the foundation has produced the theory of variable stiffness leveling.For the existing methods of variable stiffness leveling,the long and short pile foundation is a method that can adjust the foundation stiffness strongly and is easy to apply in engineering practice.However,when applied to actual projects,the specific pile plan and guiding implementation measures have not been formed,which hinders the comprehensive promotion of this method.Therefore,more research is needed in this direction.This paper uses ABAQUS software to analyze the results using three-dimensional finite element analysis combined with engineering examples.The research is carried out on the method of using independent cap foundation,long piles and piles under independent caps,and piles and piles under pile piles to reduce the differential settlement of the original plan.Through analysis,this article has the following results:(1)The finite element calculation and analysis of the single pile is compared with the results of the engineering test pile to verify the reliability of the parameters selected by the finite element calculation.(2)The load-settlement analysis of each platform of the original project is carried out.On this basis,the settlement calculation method of the cap is proposed.And by superimposing the self-settling and additional settlement of the cap,the settlement of the original plan is large in the middle and small in the corner.(3)Four kinds of independent pile cap piles are proposed.The settlement of each plan is obtained by finite element calculation analysis and settlement superposition calculation.The comparison between the four corners and the upper and the right side long piles is the independent cap.Under the scheme of better differential settlement control,the relationship between the long pile control area ratio and differential settlement under independent pile cap form is analyzed.(4)Based on the original scheme,the pile-raft foundation pile form is proposed.Through the finite element analysis,the settlement of the foundation is large and small.(5)Three pile-type long-short-base schemes are proposed.The schemes for analyzing and comparing the original schemes and finding that the corners and peripheral long piles are shortened and steepened are the schemes for reducing the differential settlement of the original scheme,and the pile-rafting method is analyzed.The relationship between long pile control area ratio and differential settlement.