In response to the application of rotary excavation and expansion pile technology in bridge foundation construction in soft soil areas,it is difficult to provide effective technical guidance directly based on construction precedents and specifications under ordinary geological conditions.Taking the Feiyun Bridge on Hutai Road in Section 2 of the Xinchuansha River section of the Wusong River Project(Shanghai section)as an example,it optimizes the construction process of rotary excavation and expansion pile construction in soft soil areas from four aspects:mud ratio,mud circulation system,drilling technology and bottom expansion technology.The results show that the optimized construction process can ensure high pile quality,save costs,and achieve good economic benefits.It has certain reference significance for similar projects to carry out bridge rotary excavation and expansion pile construction under soft soil conditions in the future.
mud ratiomud circulation systemdrillingexpanding the bottom