水布垭水电站左岸防淘墙竖井法施工关键技术

Key technology for construction of anti-scour wall by shaft method on the left bank of Shuibuya hydropower station

水布垭水电站防淘墙施工采用竖井法分层开挖、分层浇筑逆作法施工方案,该方案是复杂地层中水下防淘墙施工的一次大胆尝试和成功突破。施工中应用多项关键技术,解决了一系列施工难题。应用打"活套管"技术,解决了深厚覆盖层固结防渗的难题,节约了成本;应用控制爆破技术,避免爆破振动对紧贴新浇筑混凝土的损伤及对滑坡体稳定的影响;应用混凝土向下泵送技术,解决48m高落差混凝土浇筑难题;并首次应用"大竖井"代替"小竖井"方案,成功解决了深厚覆盖层(最深25.7m)中防淘墙施工的难题。该项目比合同工期提前4个月完成施工任务,创造直接经济效益676.89万元,为水布垭水电站提前发电做出了重大贡献,也为今后同类地质条件下防淘墙施工提供借鉴。

Reverse construction option is applied for construction of the anti-scour wall of Shuibuya hydropower station by shaft method, according to it, the anti-scour wall was excavated and placed in layers. The option proves that the underwater construction of the anti -scour wall is a bold attempt and successful breakthrough. Some key technologies are used during construction to deal with a series of challenges. By applying the ＂movable sleeve＂ technology, the problem of consolidation and seepage control of deep overburden was solved and cost was saved; by applying the control blast technology, the impact of blast vibration on newly-placed concrete and the slope stability was avoided ; and by pumping concrete downward, the difficulty of concrete pouring at a 48 m high drop was overcome. The option of replacing ＂small shaft＂ with ＂large shaft＂ is used for the first time, by which the problem of constructing anti-scour wall in deep overburden （25.7 m deep at max. ） was successfully solved. The project was completed 4 months ahead of contract construction period, creating a direct economic benefit of 6. 768 9 million Yuan and making a great contribution to power generation of Shuibuya hydropower station in advance, which provides references for future anti-scour wall construction in similar geological conditions.