关键词: 地下厂房, 单孔声波, 钻孔电视, 围岩松弛

Abstract: The underground powerhouse of large-scale hydropower station is large, and the relaxation zone will be formed in surrounding rock due to structural relaxation and stress relaxation in the process of blasting excavation. Generally, the sound wave detection and borehole TV method are used to monitor the relaxation depth and change trend of surrounding rock, which provides basic data for optimization of excavation of underground powerhouse cavern and for analysis and research of surrounding rock stability. With the continuous excavation of underground powerhouse, the distance between the top arch and the excavation base is getting further and further, so it is difficult to detect the relaxation of surrounding rock at the top of the powerhouse at the base, which often leads to data lack in the middle and later stages of excavation. In this paper, the relaxation depth of surrounding rock at the top of underground powerhouse of a large hydropower station is detected from the observation well in the anchorage holes above the underground powerhouse, which provides a new idea for monitoring of the relaxation depth of surrounding rock and offers reference for other similar projects.

Key words: underground powerhouse, single-hole sonic, borehole television, relaxation of surrounding , rock