沅江特大桥卵石围堰膏浆防渗支护技术

The Paste-Slurry-Anti-Seepage-Support Construction Technique for the Pebble Cofferdam of the Yuanjiang Mega Bridge

在沅江特大桥基础施工过程中,因卵石取材方便,造价低,水中墩大部分使用卵石作为围堰的填筑材料,但卵石围堰存在严重的架空结构和大量流动水,造成后续开挖施工防渗支护难度大,给施工带来不便。通过对比常见的土石围堰防渗技术,确定使用水泥膏浆作为防渗支护结构,并研究了膏浆灌注的材料性质和工艺参数,为动水下块石架空桥墩土石围堰进行防渗支护施工提供了一种有效、经济的施工技术。

In the process of the construction of the Yuanjiang Mega Bridge,pebbles are used as the filling material of the cofferdam for most of the piers in water because they are readily available.However,there are serious impending structures and a large amount of flowing water existing in or around the cofferdam,which result in greater difficulty in the subsequent excavation and the anti-seepage support,bringing much inconvenience to the construction.Upon the basis of comparing this anti-seepage technique with that of the common earth-rock cofferdams,the anti-seepage support structure with cement-paste-slurry is chosen and adopted for the project,with the material properties and process parameters of the paste-slurry studied.The construction of the anti-seepage support for this project provides an effective and economical construction technique for the anti-seepage construction of an earth-rock cofferdam for the rock-block-overhanging bridge pier in flowing water.