金龙滩闸室底板减薄后闸室安全性评价

Safety Evaluation of Gate Chamber after the Thinning of Chamber Floor in Jinlongtan Hydropower Station

金龙滩水电站工程施工过程中,由于受到外界因素影响,3、4号闸孔底板施工进度拖后,为确保工程度汛安全,泄洪闸基坑在开挖0.8～1.4 m后,不得不浇筑钢筋混凝土,故实际底板厚度小于设计要求。为增强底板刚度,浇筑后,在底板每个固结灌浆孔中浇筑浅锚桩,并在3号闸墩及基岩接触部位增设20根深锚桩。采取上述措施后,闸坝经受住了恶劣工况的考验,底板未发生明显破坏。这一实例也表明,采用规范推荐的基床系数法计算基岩上的闸室底板应力偏于安全。

The construction of No. 3 and 4 gate chamber floors in Jinlongtan Hydropower Station are delayed because of external factors. For ensuring the engineering safety in flood season, the foundation pits of these chambers are reinforced by pouring concrete after the foundation pits are excavated with depth of 0.8-1.4 m which are less than design values and lead the actual floor thicknesses less than design requirements. For enhancing the stiffness of floors, the shallow anchor piles are poured in each consolidation grouting hole after consolidation grouting, and 20 deep anchor piles are added in the position of gate piers and the contact area of bedrock in No. 3 gate chamber. There is no obvious damage in completed gate chamber floors after severe flood discharge. This case shows that the chamber floor stress calculated by bedrock coefficient method in Specification has larger safety margin.