关键词: 地下洞室, 分步开挖, 岩爆, 侧压力系数, 数值分析

Abstract: In order to analyze the mutual influence of different layers stresses in the progress of every excavation step and take advantage of the former rock burst situation to predict the rock burst intensity of later layer, numerical calculation and in-site supervision measure are adopted to conduct a series of calculations and analysis. The results show as follows. When horizontal stress and vertical stresses of the initial stress field are equal, the stresses of vault, corner and the floor increase significantly at early period, and smaller increase later, gradually stabilized with the excavation progress. If the former layer rock burst appears, the vault, corner and floor of the later layer rock burst appear too. Cavern excavation has greater risk of rock burst at early period and would be smaller later. When the initial stress field dominated by the horizontal stress, with the ongoing excavation steps, the stress of the vault, corner and the floor have no large increase at early period, but later period changed rapidly. The greater the lateral pressure coefficient is, the greater the rock burst risk of the later layer is in case that the former layer rock burst appears. Finally, it is proved that the correctness of analysis results by comparison with the actual excavation. The results provide a new idea to predict underground cavern stability of later excavation layer by using the interaction among the characteristics of every layer

Key words: underground cavern, excavation by steps, rock burst, lateral-pressure coefficient, numerical analysis