溪洛渡水电站高拱坝建基面处理与安全监测

Treatment and safety monitoring of foundation surface of high arch dam of Xiluodu Hydropower Station

金沙江溪洛渡水电站大坝为我国目前已建和在建装机容量最大的高拱坝。开挖揭示大坝建基面局部存在Ⅲ2、Ⅳ级岩体和层间、层内错动发育等地质缺陷,河床坝段基岩面以下20 m处存在约15%的Ⅲ2级岩体,严重影响大坝及基础的整体稳定。通过优化建基面设计和置换混凝土、加强固结灌浆、刻槽、锚固、防渗和清基等一系列的处理措施,建基面岩体质量得到了明显的改善。监测成果显示,随坝段浇筑混凝土上升,建基面应力和沉降均匀增大,相邻坝段差异沉降较小,坝基防渗性能好,坝基和坝体的整体稳定性较好。总结溪洛渡水电站高拱坝建基面处理和监测,对类似工程具有指导和借鉴作用。

The Xiluodu Hydropower Station has a high arch dam. Geological defects such as 1II2 and IV grade rocks and inter- layer sliding belts are found in dam foundation by excavation; III2 grade rock constitutes 15% of the rock mass of 20m below foundation surface of the riverbed dam blocks, which seriously affect the overall stability of the dam and its foundation. The quality of dam foundation rock mass is obviously improved through a series of measures such as the optimization of foundation design, replacement of concrete, enhancement of consolidation grouting and so on. The results show that the stress and settlement of foun- dation surface uniformly increase with the rise of dam monoliths; the differential settlement is small in adjacent dam blocks. In addition, dam foundation has a good effect of seepage prevention, the overall stability of the dam foundation and dam is rather better. The summary of the treatment and monitoring of foundation surface of high arch dam of Xiluodu Hydropower Station can provide some references for other similar projects.