Abstract:

In order to depict the discrete properties near the retaining wall on the meso-scale, while efficiently reduce particle numbers and save computation time, based on coupled discrete-continuous approach, a retaining wall under seismic excitation in centrifuge model test is simulated. Particle flow code(PFC), which is based on discrete element method, is used to simulate sands near the retaining wall, while the domain containing particles away from the retaining wall is simulated as continuous media by the fast Lagrange analysis of continua (FLAC). The motion of the retaining wall is governed by a self-edited dynamic finite element program which is added to PFC. Coupling is achieved by interchanging data between the two software during each time step. The essence of the coupled approach includes two parts: (1) fulfilling the continuity between the discrete and continuous domains; (2) the macro parameters of the granular material should be in accordance with those used in continuous model. A new approach for picking up coupled forces and a free-vibration column simulation method are presented as supplements to satisfy the two above mentioned requirements respectively. It is shown that, on the meso-scale, the coupled method can well describe the concerned zone and the interaction between the retaining wall and the particles.

Key words: coupled model, discrete element method, free vibration column, retaining wall