乌东德水电站坝肩边坡及深基坑开挖方案研究

Study and planning on excavation scheme of dam abutment and deep foundation pit of Wudongde Hydropower Station

乌东德水电站坝址区域地形陡峭,坝肩边坡开挖量大,施工道路布置困难。为确保按期完成坝肩边坡及深基坑开挖施工,结合两岸坝肩高陡边坡现状及开挖施工工期紧等特点,分析比较了几种开挖施工方案的优缺点,提出了坝肩上部采用道路运输法开挖、中部采用溜井法施工、下部采用截流后推渣下河在基坑出渣的开挖施工方案。通过分析大坝及水垫塘基坑开挖的施工特性,提出了上部覆盖层开挖量大,宜采用明路与隧洞结合,多布置施工通道以实现高强度开挖施工,下部开挖量逐渐减小,且以岩石开挖为主,施工通道以隧洞为主进行石方开挖的施工方案。

The construction organization for Wudongde Hydropower Station is encountered with challenges such as steep ter- rain, large excavated volume and narrow space for road layout. In view of the tight construction schedule, the advantages and dis- advantages of several construction schemes are compared to ensure the timely excavation of dam abutment and deep foundation pit. The construction scheme is put forward, namely, the road transport means is applied for the upper part of abutment excava- tion, the chute construction method is used for the middle part, and the spoiled materials pushed directly into the foundation pit after river closure for the lower part. The construction planning is also presented for excavation of dam foundation pit and water cushion pond. The integration of road and tunnels was adopted for upper part of the foundation pit excavation due to the deep o- verburden layer, and the construction path were arranged as many as possible to realize the high - intensity construction; the construction path for lower part were mainly tunnels because the excavation is reduced and dominated by rock material.