三峡库区某大桥深水基础施工方案研究

某大桥位于三峡库区，桥址所在河谷呈“U”形。桥型设计为预应力混凝土连续刚构，主墩基础采用高桩承台基础。由于三峡水库从2009年开始正式蓄水，水库常年蓄水位在145～175 m之间变化，变幅达30 m，在水库里进行大型桥梁的基础施工存在水深大、施工期水位变幅大等困难。大桥在水库高水位时（长江枯水期）采用固定式施工平台施工桩基础，在低水位时（长江汛期）下放钢吊箱围堰施工承台及桥墩。该方案安全性高，经济性好，工期短且易于保证。

Research on the Construction Scheme of the Bridge Foundation in Deep Water in the Three Gorges Reservoir

A bridge is located in the Three Gorges Reservoir,where the valley showsUType.The bridge is designed as prestressed concrete continuous rigid frame.The main pier foundation is high pile foundation.Because the Three Gorges Reservoir started water storage in 2009,and the perennial water level varies from 145 to 175m with a variation of 30m,there are difficulties in foundation con-struction of large bridges in the reservoir with great water depth and large variation range of water level in construction period.The pile foundation is constructed in the high water level of reservoirs （the Yangtze River during dry season）using a fixed type construction platform,and the cap and pier is constructed in the low water level （the Yangtze River flood）using steel suspension box cofferdam.The scheme has high security,good economy,and short construction period and is easy to be guaranteed.