English：

In this paper, the hydraulic double⁃wheel milling and mixing ( cutter soil mixing, CSM)method wall of the south anchorage caisson foundation of Hannan Yangtze River Bridge is taken as theresearch object. The project is adjacent to Yangtze River levee. The environment of the construction areais complex, the groundwater level is high, the sand base stratum is connected with the river water, thesite water level changes significantly with the seasons, and there is a hydraulic channel, which is easy tocause piping and other risks. The construction period of the foundation of the anchor caisson covers theflood season of Yangtze River. In order to avoid the impact of the flood season on the construction of thecaisson, a circular bottom dropping hydraulic double⁃wheel milling mixing construction wall with an innerdiameter of 132m is set around the caisson. The numerical calculation results show that the requirementsare met under different conditions of caisson sinking. Through the process test, the equipmentperformance requirements were optimized, and the drilling⁃milling construction technology was innovatedto improve the construction efficiency, ensure the wall perpendicularity and rock penetration depth,optimize the sectional “four milling and four spraying” wall forming technology and cement mixing ratio,and core sampling verified the integrity, strength and permeability of the wall, ensure the safety of YangtzeRiver embankment and surrounding environment, and ensure the smooth sinking of the anchor caisson.