大花水水电站坝基开挖施工技术

Excavation Technology for Dam Foundation of Dahuashui Hydropower Station

大花水水电站地形较为复杂，拱坝两坝肩为70°陡壁，施工前期因20t走索线尚未形成，坝肩开挖无法采用大型的施工机械。根据特有的施工条件，坝肩开挖主要采用潜孔钻和手风钻进行钻孔，底面采用了35°～45°的斜层面开挖，以便爆破后石渣自动滚落至基坑，减小人工清渣量，加快施工进度；在拱坝坝基基坑开挖时，采用了大型的机械设备进行施工，保证了施工进度，为一枯拱坝碾压混凝土顺利浇筑至755m高程打下了基础。

There are high slopes with angle of 70° on both of dam abutments of Dahuashui hydropower Station. Under the condition that large-scale construction machines could not be used, submerged and hand drills are mainly used for excavation of abutments. Excavation of inclined bench with angle of 35°-45°was adopted resulting in that ballast can automatically roll down into foundation ditch after explosion. When the arch dam foundation ditch is excavated, large-scale machines are adopted. This technology could ensure construction schedule.