Study On Settlement Calculation Method Of Pile Group Foundation Considering Pile-soil Effect

In recent years,the number of high-rise buildings has gradually increased,and pile foundations have been widely used in high-rise building foundations.Due to insufficient research on the complex mechanical behavior of pile-soil interaction,the current calculation method of pile foundation settlement is not yet perfect.At present,the simplification more commonly used in engineering is to calculate the settlement of group pile foundations based on the Mindlin solution’s Geddes method,but the calculated value is far from the actual value.In this paper,with the help of finite element analysis software,a model is established to analyze the reasons for the deviations in settlement calculation using the Geddes method based on the Mindlin solution under different pile numbers of single pile,multiple pile and group pile foundations.Through analysis,the soil assumed by the Geddes method is completely elastic,different values of α and β,different bearing layers at the pile end,and whether or not the bearing platform is considered will all affect the results,but the Geddes method uses piles and soil to interact with each other.The acting force is assumed to be that the vertical force is the most important factor causing the deviation.For group pile foundations,the deviation rate of the Geddes method is more than 200%,and the deviation rate of the Geddes method after using shear stress instead of vertical force is less than 20%,which is more than ten times the difference.Based on the analysis of the Geddes method based on the Mindlin solution,this paper improves the Geddes method,uses shear stress instead of the vertical axis force,and proposes a simplified finite element method for the finite element method to calculate the settlement of pile groups.A large-area group pile model was established to verify the feasibility of the simplified finite element method,and the factors affecting the accuracy of the simplified method were discussed.The simplified finite element method replaces the pile with the shear stress of the pile-soil contact surface,and no pile elements are created during the analysis.The simplified finite element method has the advantages of reducing operation steps,saving calculation time,and reducing modification costs.Through analysis and improvement,the simplified finite element method is in good agreement with the finite element method considering pile-soil contact,which provides a new idea for calculating the pile foundation settlement using the finite element method in engineering.