关键词: 地下洞室群, 开挖支护, 围岩变形, 蚀变岩体, 杨房沟水电站, 雅砻江

Abstract: The underground caverns of Yangfanggou Hydropower Station on Yalong River have compact construction arrangement, complicated geological conditions and large amount of excavation and support. In the process of construction, according to the actual geological conditions, we optimized the supporting parameters in time and adjusted the excavation method, establishing a rapid response system of design, construction and monitoring feedback, which successfully help completed the powerhouse excavation. At the same time, the effective measures such as applying advanced equipment and optimizing the technology were carried out in combination with the field practice, which greatly reduced the safety risk and accelerated the construction progress. The monitoring results showed that the surrounding rock deformation was always controlled within the allowable range. After the excavation, the surrounding rock deformation of the main and auxiliary workshop tended to stabilize. Even under the influence of poor geological conditions and increased support, 6 months ahead of schedule to start concrete pouring was successfully realized.

Key words: underground caverns, excavation and support, surrounding rock deformation, alterated rocks, Yangfanggou Hydropower Station, Yalong River