Abstract: In the aim of revealing the bearing behavior of single pile and the interaction between pile and soil in self-balanced test of foundation pile, DEM software PFC^2D is employed to simulate the loading process in the self-balanced test.Test results reveal that: (1) in the initial stage of loading, side resistance of pile was superior to tip resistance which had also some play, but tip resistance occupied a certain role with the increase of load. (2)The porosity of soil surrounding pile changed regularly in the process of loading.Within a certain scope of pile tip, soil porosity decreased, and the closer to the pile tip, the greater porosity changed; in the adjacent of load cell and upper section of pile, soil porosity increased.(3) The coordination number between soil particles, the horizontal soil stress and vertical stress, as well as the displacement of soil particles surrounding pile changed regularly with the increase of load. The research results would offer support for the theoretical study on self-balanced test of pile.

Key words: foundation pile, self-balanced test, particle flow, numerical simulation, bearing behaviors, meso-study