Field experimental investigation on bearing characteristics of super-long pile under dynamic compaction in land reclamation area

Abstract

To investigate the bearing mechanism of super-long piles in reclamation, this study performed a series of field tests on super-long cast-in-place piles. The load distribution and bearing characteristics of the piles were analyzed, and the bearing capacity calculation method was evaluated. The findings revealed that dynamic compaction (8000 kN·m) improved the compactness and bearing capacity of the filled soil, and was capable of avoiding negative friction around the pile. The pile bearing characteristics were friction type, and bearing capacity was mainly borne by axial friction resistance. The pile end resistance accounted for 15.7 %–35.1 % of the bearing capacity, and the peak friction resistance was distributed in the upper soil at a depth range of 0.13–0.31 times pile length. The measured value of friction resistance was 9.8 %–90.2 % higher in the upper soil layer and 46.7 %–60.8 % lower in the rock layer than the value recommended by the current Chinese code. The hyperbolic model overestimated the bearing capacity by 26.8 %–50.4 % and the exponential model error was -4.5 % – +18.9 %. The hyperbolic model was corrected, and the correction factor was determined as 0.73. This study provides guidance for the structural design and theoretical calculation of super-long piles in reclamation areas.