Evaluation of stability and reinforcement effect of surrounding rock of the underground powerhouse of a hydropower station

Abstract

The stability of surrounding rock of underground cavern is related to the construction safety of underground engineering and the safe operation of underground buildings in the later stage. The stability of surrounding rock of an underground powerhouse in southwest China is evaluated based on the type check of surrounding rock in construction geology and the analysis of block stability. And through the comparison and analysis of the displacement monitoring data of surrounding rock during construction period and the result of FLAC^3D numerical simulation, the reinforcement effect of surrounding rock is evaluated. The evaluation results show that the surrounding rock of the underground powerhouse mainly consists of class Ⅱ and Ⅲ surrounding rock, accounting for 96%, and class Ⅳ only accounts for 4%. Moreover, due to timely reinforcement, large-scale block collapse of more than 10 m³ did not occur during construction, and the surrounding rock stability is generally good. The displacement of the top arch of the surrounding rock of the underground powerhouse is millimeter, and the reinforcement effect of the top arch surrounding rock is good. The displacement of side wall is in the order of cm, and the reinforcement effect of side wall surrounding rock is preferable good. Comparatively speaking, the reinforcement effect of the top arch is better than that of the side wall. The research results can be used as reference for similar projects.

Keywords

underground power house / classification of surrounding rock / rock block stability / reinforcement effect