Abstract: The soil compaction effect of pile penetration increases soil pressure on the pile shaft. Analyzing soil pressure changes caused by pile penetration is significance for establishing a calculation method for pile penetration resistance. The large deformation numerical simulation method and Nanshui soil model were used to analyze the pile penetration process in sandy soil. The variation of soil pressure coefficient K under different working conditions was analyzed. Numerical analysis results indicate that the change in soil horizontal stress during the pile penetration process can be divided into three stages: loading, unloading and stress stabilization. The soil horizontal stress peaks when the pile end reaches a certain depth, and then the soil enters the unloading stage as penetration continues, and finally stabilizes. The maximum disturbance range is 5D in the depth direction and 6D in the radial direction. Soil pressure on the pile shaft after penetration is approximately linear, with extreme values at the pile end. The change in pile diameter has an insignificant effect on soil pressure, and the soil pressure on the pile shaft with different diameters is similar. As the interface friction coefficient increases, the soil pressure on the pile shaft gradually rises. Based on the numerical analysis results, a method for calculating pile shaft soil pressure considering the pile-soil interface friction coefficient is proposed.

Key words: sand soil, soil compaction effect, soil pressure coefficient, large deformation numerical simulation