三峡工程围堰若干关键技术研究与实践

Research and application of some key technologies for the cofferdams of Three Gorges project

三峡工程施工导流采用"三期导流,明渠通航"方案,先后修建了一期土石围堰和碾压混凝土纵向围堰、二期上下游土石围堰、三期上下游土石围堰、三期碾压混凝土围堰,共五道土石围堰和两道碾压混凝土围堰,总的规模和难度均在世界前列。围堰在设计和施工过程中,成功地解决了土石围堰基础新淤沙处理、塑性混凝土防渗墙、振孔高喷、常规高喷、钻喷一体化和自凝灰浆综合防渗技术,以及碾压混凝土围堰快速施工和爆破拆除等若干关键技术问题,极大地推动了国内外围堰技术的发展。

The scheme of three phases of river diversion during construction together with open channel for river navigation is used in the Three Gorges project. The five earth-rock cofferdams and two RCC cofferdams have been constructed in following order： the first phase earth-rock cofferdam and the longitudinal RCC cofferdam, the second phase upstream and downstream earth-rock cofferdams, the third phase upstream and downstream earth-rock cofferdams and RCC cofferdam. During the design and construction of these cofferdams, some key technical issues have been successfully resolved. By taking the measurements of envelop, cover and cut-off, the new alluvium stability in the foundation of the earth-rock cofferdam was well treated. In order to resolve the deformable capacity and the construction speed of the cut-off walls in the earth-rock cofferdam, the plastic concrete cut-off wall, vibrating jet grouting, rotating jet grouting and self-hardening cement slurry were used. The RCC cofferdam of 90m in height was completed in 4 months by continuous lifting placement so as to create the construction speed record in the world, and the upper part of 30m in height was removed with dumping blasting technology.