某电站下水库面板及趾板混凝土裂缝处理

Treatment of concrete cracks in the face slab and toe slab of the lower reservoir of a power station

某抽水蓄能电站下水库面板及趾板混凝土施工期出现了较多裂缝,裂缝以深层缝、渗水缝为主,裂缝长度1.1~13.2 m,裂缝宽度0.03~1.12 mm,其中面板裂缝基本为规则横向,趾板裂缝垂直于趾板延伸方向,有极少数斜向裂缝、X型裂缝、Y型裂缝,初步分析裂缝的产生主要与混凝土干燥收缩、温度变形、基础约束等因素有关。针对Ⅰ~Ⅳ类不同类型的裂缝,分别采用了表面封闭、封缝无损贴嘴+表面封闭、切线槽化学灌浆+表面封闭、凿槽封缝后化学灌浆+表面封闭等不同方法进行处理。蓄水前压水试验检查结果表明,裂缝处理效果良好,缝内填充密实,裂缝隐患得到有效消除。蓄水运行后未见明显渗漏,下水库运行状况稳定。

There are many cracks in the face slab and toe slab of the lower reservoir of a pumped-storage power station during the construction period.The cracks are mainly deep cracks and seepage cracks,with 1.1~13.2 m in length and 0.03~1.12 mm in width.The cracks on the face slab are basically regular transverse,and the cracks on toe slab are perpendicular to the extension direction of toe slab,with a few inclined cracks,X-shape cracks and Y-shape cracks.The preliminary analysis shows that the cracks are mainly caused by the factors such as drying shrinkage of concrete,thermal deformation,foundation constraint and et al.For cracks from classⅠtoⅣ,different treatment methods are adopted such as surface sealing,close grouting and surface sealing,slotting across cracks and surface sealing,chemical grouting and surface sealing after chute-cutting and crack patching.The results of water pressure test before impoundment show that satisfying effect is obtained from crack treatment,cracks are filled densely and defects are effectively eliminated.There is no obvious leakage after impoundment and the operation condition of the lower reservoir is stable.