Research On Rapid Construction Of Bridge Foundation In Complex Stratum In The Yellow River Reservoir Area

The speed of pile foundation is directly related to the time of the whole bridge construction for bridges in complex and deepwater environment.In the Yellow River Reservoir area,the geological conditions are complex,the water level changes greatly,and large-scale equipment cannot enter the water area due to the factors such as flood discharge,sand discharge,water storage and power generation,which seriously restricts the speed of bridge foundation construction.with lacking in-depth and systematic research,it is a problem faced by the local that how to improve the construction speed of bridge foundation.Based on the deep-water foundation construction of the main bridge of Yunbao Yellow River Bridge,this paper studies The foundation rapid construction realized by the construction technology innovation.The main contents are as follows:(1)The development process of bored pile construction technology and the current situation of bridge foundation construction is summarized,and the difficulties faced by bridge foundation construction in the Yellow River Reservoir area is analyzed,which show that the difficulties of foundation construction in the deep water area without navigation and the necessity of rapid construction.(2)Based on the comparison and selection of the schemes,the construction scheme of "auxiliary pile + simple support guide frame" is put forward,which solves the technical problem of steel casing sinking and placing deviation in the water area with large flow velocity,which is not navigable in the Yellow River.The technical characteristics of rotary drilling for the construction of super long pile foundation in super thick pebble stratum are introduced.(3)Established a new type of cofferdam structure model of "U-shaped steel sheet pile + shaped steel" composite steel sheet pile by Midas software,and the construction method of the cofferdam is studied.(4)Applied a set of mud flushing device based on the principle of "air lift reverse circulation" of pile foundation and the high pressure gas "boosting" hydraulic power,and developed a multi-functional turnover integral walkway for steel cofferdam bottom sealing,which solve the limitations of traditional technology in the construction of deep water,deep buried cushion cap mud suction and bottom sealing.