安庆长江大桥3号墩钢套箱围堰施工技术

宁安铁路安庆长江大桥主桥为101.5＋188.5＋580＋217.5＋159.5＋116（m）三索面钢桁梁斜拉桥。桥梁主塔墩3号墩位于主河槽通航航道上,施工水位深,河床覆盖层浅,覆盖层下面为强风化光板岩,岩面高低不平;承台为圆形,直径大,桩基础为3.0 m/3.4 m变直径摩擦型钻孔桩。3号墩基础施工采用双壁钢套箱围堰方案,先围堰,后钻孔。钢套箱外径56 m,高42.88 m,属大型钢围堰。从围堰组拼、下水、浮运、定位、下沉等方面,详细介绍了宁安城际铁路安庆长江大桥3号墩钢套箱围堰的施工技术,为以后同类工程的施工提供借鉴。

The Construction Technique for the No.3 Pier Steel Case Cofferdam of Anqing Changjiang River Bridge on Ning-An Railway

The main bridge of Anqing Changjiang River Bridge in Ning-An Railway is three rope fan and steel truss slant pull bridge,which is composed of 101.5＋188.5＋580＋217.5＋159.5＋116（m）.The No.3 pier,the main pier,lies in the main riverbed Navigable channel characterized by deep water,shallow riverbed＇s cover,strong weathering sleek under the riverbed＇s cover an uneven rock;while the cushion cap is circle with big diameter and variable diameter sliding drilled pile with pile foundation at 3.0 m/3.4 m.Double-wall steel case cofferdam is used in the No.3 pier foundation construction with cofferdam constructed first followed by drilling.The steel case cofferdam has an outside diameter of 56 m and height of 42.88 m which make it a huge cofferdam.The paper introduces the construction technique for the No.3 pier steel case cofferdam of Anqing Changjiang River Bridge through assembling,launching,transportation by driving,location,and sinking,and it can provide the reference for the same bridge construction in the future.