自浮拆除式双壁钢围堰及其升降平台的设计与应用

Design and Application of Self Floating Demolition Double Wall Steel Cofferdam and Its Lifting Platform

结合昌赣铁路吉水赣江特大桥工程,针对其主墩基础水位深,水流流速快,现场场地有限,围堰下水难度大、围堰水下拆除成本高、安全风险大等难题,设计了一种水中下放升降平台(获专利),通过在水中打设钢管桩作为平台支撑吊点,贝雷梁为拼装平台的纵横向承重梁,精轧钢、千斤顶进行平台升降,实现了围堰快速下放;并设计了一种自浮拆除式双壁钢围堰(也获专利),通过改进钢围堰结构,增设置竖向、水平隔舱板,将围堰设计为多空腔结构,设置钢管桩及锚碇系统作为上浮的导向系统,在底部位置沿环向将围堰上下层分离后,抽水使钢围堰整体自浮后进行水上拆除。现场应用表明,该设计成功解决了双壁钢围堰下水、拆除的难题,这对以后类似双壁钢围堰设计、施工具有借鉴意义。

In combination with the project of Jishui Ganjiang River Super Large Bridge on Nanchang-Ganzhou High-speed Railway,the problems such as deep water level of main pier foundation,fast flow velocity,limited site,difficult launching of cofferdam,high cost of underwater demolition of cofferdam and high safety risk are analyzed.A kind of underwater lifting platform(patented)is designed.By setting steel pipe piles in the water as the platform support lifting point,Bailey beam as the vertical and horizontal bearing beam of the assembly platform,and finishing rolling steel and jack for platform lifting,the cofferdam can be quickly lowered.A kind of self floating demolishing double wall steel cofferdam(also patented)is designed.By improving the structure of the steel cofferdam,adding vertical and horizontal bulkhead,the cofferdam is designed as a multi cavity structure,with steel pipe pile and anchorage system as the guiding system for upward floating.After separating the upper and lower layers of the cofferdam along the circumferential direction at the bottom,the whole steel cofferdam is removed by pumping water to make it float.The field application shows that the design successfully solves the problem of launching and demolishing the double wall steel cofferdam,which has reference significance for the design and construction of similar double wall steel cofferdams in the future.