三峡工程三期围堰施工技术综述

Overeview of the construction technology of the third stage cofferdam of Three Gorges project

三峡三期围堰系统是二、三期工程衔接及确保按期蓄水发电的关键性控制工程。为此,三期截流采用了垫底加糙拦石坎、双戗堤立堵进占技术,土石围堰防渗墙施工采用了振孔高喷、常规钻孔高喷、钻喷一体化高喷等工艺方法,三期RCC围堰施工首次把集混凝土水平运输、垂直运输、仓位布料于一体的塔带机作为碾压混凝土的主要运输工具,成功地解决了浇筑过程中骨料分离、集中、层间结合不良的问题;并采用连续翻转与台阶模板以及全新的入仓口设施与汽车冲洗设备及新型防渗技术,实现了提前截流、提前抽水、提前挡水的目标,工程质量满足合同及规范标准。

The third stage rocldill cofferdam is the key link between the second and the third stage work to secure the reservoir filling and power generation on schedule. Therefore the schemes of riverbed rock retaining sills, and vertical double-prop weir were used and for the construction of cutoff wall of the third stage rockfill cofferdam, the vibrating hole with high grouting, conventional hole with high grouting and combination of boring and high grouting were adopted. For the construction of the third stage RCC cofferdam, the tower and belt conveyor ,which has the functions of horizontal and vertical transportation and placement of concrete had been used as the principal RCC transportation means. By so doing, the problems such as the degradation, concentration of the aggregates and inadequate bond between lifts resulted from transportation. The continuous overturning and step forunwork and brandnew hopper devices, truck washing equipment and newly developed seepage control technology contributed to the closure of river, pumping of water and damming of water in advance and totally met the requirement of the contract and specifications.