关键词: 地下矿山, 多中段联合开采, 开采扰动, 数值模拟, 围岩稳定性

Abstract: Multi-level simultaneous combined mining is easy to produce mining-induced superim⁃ posed disturbance，which induces stress redistribution，deformation and instability disasters of surround⁃ ing rock. It is a prominent problem faced by efficient mining of underground mines. Taking a sedimentary metamorphic iron mine as the engineering background，a three-dimensional numerical model with a size of 700 m×100 m×450 m was constructed by field engineering geological investigation，rock mass classifica⁃ tion and reduction of mechanical parameters of Hoek-Brown and M.Georgi criteria for the collaborative mining conditions of -400 m and -500 m double middle sections. FLAC numerical simulation system was used to explore the evolution law of surrounding rock displacement，stress and plastic zone in the whole process of multi-middle section progressive mining. The results show that the multi-middle superimposed disturbance mainly causes the roof subsidence of No.I ore body，and the maximum subsidence displace⁃ ment is 38.8 mm. In the later stage of mining，there is a significant tensile stress concentration in the 409 section of No.I ore body，with a peak value of 3.50 MPa，which exceeds the tensile strength of the ore rock by 2.50 MPa，and there is a risk of local tensile failure. The stress and deformation in the remaining areas are less than the ultimate strength of the rock mass，and the overall stability is controllable. The plastic zone is mainly developed in the top and bottom of the ore body and the segmented contact position，and there is no large-scale penetration failure. Based on the response characteristics of surrounding rock distur⁃ bance，the prevention and control scheme of staggered mining in the middle section，pilot stope first and filling with mining is established to effectively avoid the risk of ground pressure disaster. The research re⁃ sults can provide theoretical basis and engineering reference for safe and efficient collaborative mining of multi-level in similar mines.

Key words: underground mine, multi-level combined mining, mining disturbance, numerical simulation, stability of surrounding rock