水布垭水电站防淘墙墙体开挖施工技术

Excavation construction technology for scour prevention wall at Shuibuya Hydroelectric Power Station

水布垭水电站防淘墙工程地质条件差,施工部位常年处于清江正常水位以下,施工难度大,工艺复杂,尤其是墙体开挖,采用自下而上分层施工,部分覆盖层较深部位采用宽竖井施工方案。通过施工,总结出一套适合深埋地下、地质条件复杂、地下水丰富、无法采用先进机械设备的洞室开挖施工方法和技术措施:在地质条件较好岩层,适当增加每层墙体施工高度;地质条件较差时,减少每层墙体施工高度,并做好支护;在覆盖层较厚时采取了宽竖井施工方案。施工实践表明,该施工方案是可行的。

In consideration of the poor geological condition of Shuibuya Hydroelectric Power Station, the high difficulty in construction caused by lower site of construction which was located below the normal water level of Qingjiang River, the complex construction technology, the short time limit of the project, and especially the stratified construction from bottom to top in scour prevention wall excavation and the wide vertical shaft construction scheme adopted for deep overburden layers, a series of construction methods and technical measures of cavern excavation were proposed, which were suitable for deep underground, complex geological condition and abundant groundwater where advanced mechanical equipment could not be used. The measures are as follows： for the rock stratum with better geological condition, the construction height of each layer of the scour prevention wall could be enhanced properly ; for the rock stratum with worse geological condition, the construction height of each layer of the scour prevention wall should be reduced, and the structural support is provided; the wide vertical shaft should be adopted when the overburden layer is relatively thick. Practice shows that the construction scheme is feasible.