关键词: 围堰, 防渗墙, 塑性混凝土, 帷幕灌浆, “两钻一抓循环钻进法”, 爆破工艺, 乌东德水电站

Abstract: The cut-off wall, thickness of 1.2m and the maximum depth of 97.54m, of cofferdam in Wudongde Hydropower Station is characterized as complex geologic conditions such as super large boulders and steep rock under the cofferdam, so it is difficult to construct a deep and thick impervious wall on the cofferdam. In this paper, the selection of construction equipment and machinery tools, pore forming and trenching technology and bedrock identification technology are introduced, including "two drilling-one grasping cycle drilling" and "four plus two blasting". The practice shows that the new technology provides important support for ensuring the safety of construction and speeding up the construction progress.

Key words: cofferdam, cut-off wall, "two drilling-one grasping cycle drilling", "four plus two blasting method", Wudongde Hydropower Station