Research On Deepwater Foundation Construction Technology Of The 5# Main Tower Pier In Monghua Railway Bridge Over Dongting Lake

At present,with the improvement of national economy and the implementation of transport infrastructure construction, the large span bridges of deep water which locate in the Yangtze River Basin and coastal channel are gradually increasing and the construction technology of deep water which is used to bridge also achieves rapid development. But the foundation construction of deep water which is especially influenced by geological, hydrological, environment, equipment of bridge construction and other factors has become the focus and difficulty to build bridges. Because of the difficulty of the foundation construction which constructs in different regions and use different engineering is different,the key that the bridge construction could be completed on schedule is largely determined by the success of the foundation construction of deep water. Accordingly the key technology of deep water is still studied by bridge builders and relevant experts.5#pier of Monghua Railway Dongting Lake Bridge which located in the lake outlet of Dongting Lake is a throat from Xiangjiang into the Yangtze River. On one hand, because it locates the main anchorage of Dongting Lake sand ship, the construction area is very narrow and the floating and positioning of cofferdam is difficult. On the other hand, the difficulty of construction is further increased owing to the main pylon of 5 #pier is buried in bare rock. The domestic bridge construction circle is no similar precedent that is used to bridge foundation construction of deep water in the two special construction environment. Author mainly discuss the construction technology of deep foundation which is located in the narrow waters and bare rock strata in this paper. Through the comparison and optimization of Bridge in 5 # Pylon Pier Foundation Construction Plan, author determine cofferdam at first then use double-wall steel boxed cofferdam program of back platform for it. Cofferdam performed use short anchor anchorage. At the same time,this paper introduce the construction process and technology of double-wall steel boxed cofferdam which are blasting and cleaning, pit box cofferdam design and manufacturing, cofferdam floating and positioning, construction of bored pile foundation and pile foundation construction.Through the research of construction technology which is used for constructing the main span 5# pier bridge of MengHua Railway and China Dongting Lake Bridge, author draw the relevant conclusion. Author want to use the research results to communicate with relevant peers who are in the field of bridge construction and hope to contribute our own meager in improving our foundation construction technology of bridge deep.