大直径深层钻孔灌注桩拔除工艺研究

Research on Pulling-out Technology for Long Bored Pile with Large Diameter

结合郑州南站连接线明挖隧道(拔桩区间)拟拔桩基直径大、桩长的特点,对桩体受力特征和拔桩工艺进行了研究。通过拔桩过程中桩周土破坏模式和桩体自身的抗拉强度分析计算,选取有效的减阻方法并应用于工程实践,取得良好效果。最后总结出大直径深层钻孔灌注桩拔除工程中桩身局部扩大、桩侧摩阻力过大和断桩等问题及相应的解决方法,供今后类似工程借鉴。

According to the characteristics of long and large diameter pile to be pulled out in the open-excavated tunnel （ pile-puling interval） in Zhengzhou, the force on pile body and the pile-pulling technology are studied. Through the analysis and calculation on failure mode of soll around the pile and tensile strength of the pile body in pulling-out process, the effective method of resistance reduction is selected to be applied in the engineering practice, and good results are achieved. The solutions of pile body partial enlarged, too large pile lateral friction and pile broken in pile pulling-out operation are summed up, which can serve as reference for the same projects.