叶巴滩水电站拱肩槽开挖质量控制技术研究

Research on Excavation Quality Control Technology of Arch Abutment Groove in Yebatan HEP

叶巴滩水电站大坝为双曲混凝土拱坝,大坝边坡地质条件复杂,具有高陡倾角、断层及层间挤压错动带,节理裂隙发育,地应力较高。复杂的地质条件以及高地应力使其开挖具有开挖高差大、开挖强度高、爆破振动要求严、建基面开挖质量要求高等特点。阐述了施工过程中根据实际地形和地质条件,采用边坡预裂爆破和梯段微差爆破的方式自上而下分层开挖、工作面反铲甩渣下基坑、基坑出渣的施工方法进行施工的实施过程。通过实施合理的爆破参数及质量控制措施,对超欠挖、平整度、残孔率及质点振速等指标进行严格控制,保证了拱肩槽开挖良好的整体效果,满足设计要求。

The dam of Yebatan hydropower Project is a double curvature concrete arch dam.The dam slope is characterized by high and steep dip angles,fault and interlaminar extrusion dislocation zone,developed joint fissure,high geostress.The complex geological conditions and high geostress make the excavation featured by large height difference,high excavation intensity,strict blasting vibration and high excavation quality of foundation surface.This paper elaborates the full construction process based on the actual topographic and geological conditions,by slope presplitting blasting and bench millisecond blasting from top to bottom excavation in layers,throwing the spoil into the foundation pit by backhoe,mucking on the foundation pit.By adopting reasonable blasting parameters and quality control,the indexes such as overbreak and underbreak,evenness,residual hole rate and particle vibration velocity are strictly controlled to ensure good overall effect of groove excavation and meet the design requirements.