中高地应力玄武岩地下洞室开挖成型研究

Study on excavation shaping of basalt underground chamber under medium-high ground stress

白鹤滩水电站采用双曲拱坝、左右岸地下引水发电系统布置方式,地下引水发电系统布置规模浩大。在中高应力地下洞室开挖施工过程中遇到了开挖成型应力破坏较为严重的问题。本文提出预留保护层给予应力释放空间的研究思路,不断探索保证开挖成型的办法,依据新奥法理论确保围岩稳定性,并将研究成果在地下电站厂房开挖施工中应用。研究所得成果可供相关地下洞室开挖施工方法提供参考。

The layout of double-curvature arch dam with underground water diversion and power generation systems on both the left and right banks is adopted for Baihetan Hydropower Station,thus the scales of the arrangements of the underground water diversion and power generation systems are quite large.During the excavation of the underground chambers under medium-high ground stress,the problem from the stress damage on the excavation shaping is encountered.The study approach of that remaining a protection layer for giving a space for stress release is put forward herein,and then the method to guarantee the excavation shaping is continuously explored and the surrounding rock stability is ensured in accordance with the theory of the New Austrian Tunneling Method,while the study achievements are applied to the actual excavation of the underground powerhouse as well.The study result can provide some references for the excavation methods of the relevant underground chambers.