Research on Bearing Characteristics of Large-diameter and Overlength Bored Pile

Research purposes: To analyze the behaviors of axial load transmission,the distribution of lateral friction resistance and the performance of resistance at pile end under different load action,to master the load transfer characteristics and bearing mechanism of large-diameter and overlength bored pile,and to provide reference and guidance for improving the design method of large-diameter and overlength bored pile. Research conclusions:The axis force of large-diameter and lengthy bored pile reduces from the upper portion of pile to the bottom portion,the rate of reduction indicates the magnitude of lateral friction resistance of pile.The function of lateral friction resistance at the upper portion of pile takes precedence of the bottom portion.Moreover,the majority of the load is born by lateral friction resistance of pile for the large-diameter and lengthy bored pile,and the magnitude of resistance at pile end is usually very small.Therefore,most of the large-diameter and lengthy bored piles are friction piles or end-bearing friction piles.