Numerical analysis of bearing behaviors of uplift piles during pit excavation

The excavation results in unloading state of the soils, which influences the original loading characteristics of uplift piles. Based on the numerical simulation method, change of the bearing behaviors of the uplift piles caused by excavation is systematically studied. The rules of ultimate uplift capacity, side friction and axial force are discussed by comparing different excavation scopes and relative locations. The results show that, excavation leads to soil rebound under the bottom, induces positive side friction in the upper part of the piles and negative side friction in the under part, and reduces the ultimate uplift capacity of the piles. Moreover, the degree of decrease is proportional to the size of the foundation excavation. The variation of side friction and axial force of the center pile caused by foundation pit excavation is more obvious than that of side pile and corner pile and change of corner pile is the minimum. The ultimate uplift capacity of the center pile is largely affected by the curtain effect of group piles.