一种新的组合桩轴压承载力计算

摘要

In order to solve the problem of large diameter pile, a new type of composite pile is put forward. The composite pile used in this study is that the continuous circular steel tube along with the longitudinal pile section is arranged in reinforced concrete pile. The mechanical mechanisms of composite pile under axial compression are analyzed. By considering the restraint effect of the steel tube and stirrups, the critical state stirrup ratio of the outer concrete is derived. With the difference of the stirrup ratio, there are two kinds of failure modes as the pile is under axial compression. The calculation formula of the axial bearing capacity of composite pile is derived in the two failure modes. The average value of the calculated and experimental ratio value is found as 1.015, with the standard deviation of 0.037, which shows a good agreement between the calculated and the measured values.%为了解决桩径过大问题,提出了一种新型组合桩形式,即在普通钢筋混凝土桩内部设置沿桩身纵向连续的圆钢管。分析了新型组合桩在轴心压力作用下的受力机理,将钢管和箍筋对混凝土的约束作用等效为有效侧向应力,推导出了临界状态时外围混凝土的配箍率。提出了随着外围混凝土配箍率的不同,这种桩在轴压下有2种破坏形式。分别推导出了不同破坏形式时轴心压力作用下新型组合桩承载力计算方法。采用该方法计算的组合桩轴压承载力与文献试验结果之比的平均值为1.015,标准差为0.037,二者吻合良好。