Abstract: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 soil 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.