Abstract: Several methods are available for account the soil aching effect in the pile-supported embankment; but these present methods produce dramatically different results partially due to the different analysis models. To avoid the macro continuity hypothesis of traditional continuum mechanics model, a two-dimensional numerical model using particle flow code(PFC) has been established to simulate soil arching effect of pile-supported embankment. One part of the numerical analysis deals with load transfer mechanisms by investigating the contact stress, stress distribution and vertical displacement. Also the simulated results have been compared with model test results. The other part of numerical analysis consists to a parametrical study investigating the influence of the size of the pile cap, pile spacing, the fill height, particle size and the friction angle of embankment. It is shown that: (1) The local soil on the top of pile can be regarded as elastic nucleus. Soil arch forms were affected by forms of the pile cap, clear spacing of pile cap and geogrid. (2) The soil aching area is located around one time pile cap clear spacing over the bottom of embankment. (3) The vertical stress and lateral stress in the inner arching vary with depth nonlinearly and pile -soil stress ratio increases with the load level , the friction angle and particle size of soil.

Key words: pile-supported embankments, soil arching effect, particle flow code(PFC), pile-soil stress ratio