Numerical simulation for the pile group in soft soil

As a result of fill placement or even lowering of phreatic surface, the soil surrounding the piles of pile foundations in soft ground settles more than the piles. In that case, negative skin friction occurs, producing pile settlement (downdrag) and additional compressive force (downdrag) due to the hanging effect around the pile. Disregarding the effect of downdrag forces on piles due to consolidation of the surrounding soil has led to damages of buildings and foundations. Many methods have been proposed to calculate the downdrag on single pile, especially by numerical simulation method. But much less work has been done on pile group downdrag. In the present paper, a numerical model is founded; deformation and stress responses are obtained as well as the mechanical response of pile group during calculation, whose result reveals the mechanism of interaction between pile with soil.