Three-Stage Analysis Method for Calculating the Settlement of Large-Diameter Extralong Piles

Abstract

In terms of safety, large-diameter extralong piles require highly accurate settlement prediction because of their high load-bearing capacity. According to the bearing mechanism of the large-diameter extralong pile, in this paper, a novel and scientifically accurate three-stage analysis method is proposed for predicting pile settlement based on Randolph’s study of pile forces in homogeneous soils, in view of the limitation that the accuracy of the conventional settlement calculation method is only applicable to the pile in the end-bearing frictional bearing condition. The three-stage analysis method fully considers the deformation characteristics of the pile in three different bearing states: pure friction bearing stage, end-bearing friction bearing stage, and damage stage. The critical load of TP4-1 in this paper is 9620.89 kN, and the ultimate compressive bearing capacity is 19279.09 kN, as calculated using the three-stage analysis method, and thus the three bearing states are clearly defined. The settlement under all levels of load obtained using this method can be very close to the real-case settlement, and the maximum error of the TP4-1 pile is only 0.52 mm, as observed by numerical simulation, static load test of TP4-1, and experiments on the other three test piles.