Bearing capacity and simplified calculation approach for large-diameter plain-concrete piles

Abstract

In recent years, the usage of large-diameter plain-concrete pile composite foundations has undergone rapid growth in China, especially for high-rise buildings. In this paper, the mechanical characteristics of large-diameter plain-concrete piles are studied by in situ monitoring and a finite element simulation. The results show that the axial force, the soil pressure, and the pile-soil stress ratio all increase simultaneously with increasing applied loads. The axial force initially increases along the pile length and then decreases. The distribution of the side friction along the pile body shows a three-segment broken-line pattern, and the positions of the maximum positive and negative friction resistance remain unchanged as the applied loads increase. Based on the pile-soil deformation compatibility derived from the in situ monitoring data and finite-element method simulation, a simplified calculation method to analyze the pile-soil interaction is proposed. Moreover, a comparison between the proposed calculation method and a finite-element simulation is given, and the result shows that the data obtained by both approaches agree well.