Construction Technology For Deep-water Huge Open Caisson Foundation

With the development of transport construction,it is necessary to build across rivers,lakes and seas,wide deepwater large bridge.The open caisson foundation,as one of the main forms of large infrastructure for large bridges acrossing deep water,has a very broad application prospects.At present,with the development of the bridge span,deep water open caisson foundation tend to become larger,the bridge structures as well as the construction technology are facing increasingly complex problems,the scale of many open caisson of bridges in our country has reached an unprecedented level of a world record,and the lack of practical reference urges the research on engineering project with very deep water open caisson techniques.In this thesis,based on the construction of Hu Tong Yangtze River Bridge kingtower open caisson foundation engineering,some key technigues on very deep water open caisson are studied in detail.On the basis of summarizing bridge large open caisson technique,combining based on engineering practice,the following problems are mainly studied.1.Engaged in the research of open caisson float-conveyance,sinking position system and construction monitoring system,problems and the dealing techniques about the open caisson float-conveyance under the conditions of different water velocity,wind speed,different depth of water draught resistance and air resistance to the open caisson accurate positioning,are studied and discussed.By using regulating the formula,the half rigid system of "steel anchor piles combined with gravity anchors" structure is calculated and analyzed,and put forward some specific measures.2.Through the monitoring analysis of the whole process of the open caisson construction,some techniques and methods for open caisson construction are proposed.Research shows that the float-conveyance on the surface of the open caisson in the windward air resistance and air resistance should not be neglected for the inner wall of the hole,and with the increase of floating speed,the lining of the rounded rectangle caisson water retaining effect more apparent.As for the open caisson position,a half rigid system containing steel anchor piles and gravity anchors is helpful to make it accurate and easy to operate.In the open caisson whole process monitoring system using real-time attitude control system based on GPS-RTK technology,can achieve a sunken well construction of attitude and safety monitoring and prediction.