Abstract: Few studies have been conducted on the mechanism and behavior of soil arching surrounding passive piles.In this paper a plane FEM is applied to assess four key factors of soil arching,such as its shape,the vertical displacement contour,plastic or tensile area of soil surrounding piles and residual stress post piling.Changes in cohesion,internal friction angle,elastic modulus,Poisson ratio,dilatancy angle,and interface conditions are evaluated respectively.The results indicate that the yield mechanisms of cohesive and non-cohesive soils around piles are different when forming the soil arching.Poisson ratio,dilatancy angle,and interface conditions play very important roles in soil arching effects.The results also demonstrate effects of interaction of pile and lateral soil movements,relationship between bypassed earth pressure around piles and soil parameters,and the discrepancy of Tomio Itos earth pressure formula.