Centrifuge Model Study of Pile Group Subject to Adjacent Excavation

In recent years, many underground infrastructures were built very close to existing buildings in urban areas. Thus the behavior of piles subject to excavation-induced soil movement needs to be evaluated. In the present study, a series of centrifuge model tests were conducted on a 4-pile group connected by pile caps with different rigidities. The bending moments and deflections for the front and rear piles within the pile group due to the staged excavation in these tests are reported in this paper. It is established that a 4-pile group connected with a monolithic rigid fixed pile cap would experience a maximum negative bending moment at the pile head and the moment magnitude is much larger than that for the same pile group connected by a flexible pile cap. However, the flexible-cap pile group would experience a much larger pile head deflection than that of a rigid-cap pile group.