EVALUATION OF VERTICAL BEARING CAPACITY OF SUPER-LONG BORED SINGLE PILE BY THE PILE HEAD SETTLEMENT

The load transfer mechanism and bearing characteristics of super-long bored single pile are addressed in this paper.A tri-linear model and a bi-linear model are adopted for the toe and the shaft resistance,respectively.An analytical solution to predict the vertical bearing capacity is obtained,taking into account various bearing status of the soil or bedrock around the pile shaft and under the pile toe.The influence of different soil strata,nonlinear behavior of the surrounding soil or bedrock,and the sediment under the pile toe are considered as well in the present solution.An idea to predict or control the axial bearing capacity of large-diameter and super-long bored piles by the allowable pile head settlement is proposed herein.With the analytical method,good agreement between the predicted and measured load-settlement variations of a few test piles is reached,demonstrating the validity of the method in engineering practice.