超大直径人工挖孔桩多导坑法施工及力学性能研究

摘要

以广西南宁九洲国际项目直径4 m 的超大直径桩为工程背景，结合工程设计施工资料、数值模拟结果和桩基检测报告，对超大直径人工挖孔桩采用多导坑法施工工艺的变形机理及超大直径桩的力学性能进行了研究。研究结果表明：（1）超大直径人工挖孔桩采用多导坑法施工，变形量较小，可保证工程施工安全。（2）超大直径人工挖孔桩采用多导坑法施工过程中，桩体护壁变截面处易发生应力集中，可能造成拉张破坏。（3）数值模拟静载试验及间接检测结果表明，超大直径人工挖孔桩采用多导坑法施工可满足基桩承载力要求。%The super large diameter artificial dig-hole pile with a diameter of 4 m in the Jiuzhou international project of Nanning,Guangxi province was taken as the engineering background,based on the design and construction data,numerical simulation results and investigation report,the deformation rules and mechanical property of the super large diameter pile was studied.The results showed that firstly,the deformation of the super large diameter artificial dig-hole pile construction by multi heading method was small,which could ensure the safety of the engineering construction.Secondly,the pile retai-ning wall would become stress concentration and be damaged at the transition section caused by multi heading construction method.Thirdly,the results of numerical simulation of the static load test and indirect test were indicated that the large di-ameter pile construction by multi heading method could meet the bearing capacity of foundation piles.