Effects of excavation and construction sequence on behavior of existing pile groups

Abstract

In congested urban areas, new structures are regularly constructed next to high-rise buildings. At different stages of excavation for the new structures, settlement and tilting of the adjacent piled buildings may be occurred. Thus, attention here will be focused on the interaction behavior between deep excavation and adjacent piled foundations. Accurate prediction of soil movement and pile response plays an important role in preventing damages to adjacent buildings. Finite-element models are employed to compute the pile group responses. The parametric study has been performed by varying pile group configurations, center-to-center pile spacing, and new building load. Two, four, and six capped head pile groups next to excavation sites have been examined. In this paper, discussion centers on settlement and tilting of the pile groups nearby an excavation in fully saturated sand. The influence of pile group configuration and new building loads are systematically investigated. New building can be constructed in the excavated area after completion of the excavation. The effect of new building construction sequences is also investigated. Results provide confirmatory evidence that, excavation depth has the most significant effect on pile settlement and pile cap tilting. High pile cap tilting and small pile group settlement are apparent in case of two piles near the excavation. For the four pile group, the induced tilting of pile cap decreases as spacing between the piles increases. Due to construction of the new building, the settlement is exacerbated but the tilting is moderated.