Numerical modelling of effects of different multipropped excavation depths on adjacent single piles: comparison between floating and end-bearing pile responses

Owing to a shortage of land, high-rise buildings are increasingly preferred to meet the development and economic growth of major cities in the world. The construction of high-rise buildings often requires deep foundations such as single piles or pile groups when the underlying soil and rock strata do not have sufficient bearing capacity. On the other hand, underground basements are constructed to facilitate inhabitants in the buildings for parking. Development of underground transportation systems consist of tunnels, excavations for basement construction and cut and cover tunnels. These excavations are sometimes inevitable to be constructed adjacent to existing piled foundations. This research presents three-dimensional coupled consolidation analyses (using clay hypoplastic constitutive model that takes account of small-strain stiffness) to investigate the responses of a floating and an end-bearing pile due to adjacent excavation at different depths in clay. It was revealed that the maximum induced bending moment in both types of piles after completion of excavation in all the cases is much less than the pile bending moment capacity (i.e. 800 kNm). Moreover, the end-bearing piles were subjected to significant dragload due to negative skin friction. In contrast, no significant changes in load distribution along floating piles were computed.