Abstract: The main powerhouse of Three Gorges underground hydropower station is with large span and thin cover, and it is rare internationally. This paper analysed the deformation monitoring data of main powerhouse wall rock of Three Gorges underground hydropower station under construction. The results showed that until the excavation end of layer Ⅵ, the maximumdeformation of the wall rock was 17.59 mm. At present, changes of displacement tend to be stable and within the allowed design range. So the wall rock of main powerhouse is stable and safe. The safety monitoring during construction stage played an important role in feeding back design and construction guiding.

摘要： 三峡地下电站主厂房跨度大、覆盖薄, 国内外少有。本文对三峡地下电站主厂房施工期的围岩变形监测资料进行了初步分析, 监测成果表明, 至主厂房第Ⅵ层开挖施工结束, 主厂房围岩深部最大变形为17.59 mm, 目前位移变化已渐趋于稳定, 且在设计允许范围内, 主厂房Ⅳ层以上围岩是稳定安全的; 施工期安全监测在反馈设计、指导施工中发挥了重要作用。