竖井开挖过程的FLAC^(3D)数值模拟

Numerical Simulation by FLAC^(3D) during Shaft Excavation Process

针对山西某矿竖井开挖过程中的变形和破坏问题,以该矿竖井检查孔资料为地质背景,以地下300~400 m地层为研究对象,基于有限差分软件FLAC3D对竖井开挖过程进行了三维数值分析,分别计算出未开挖前和每步开挖3 m后的应力和位移状态,进行井筒侧壁和底部变形规律的研究。数值计算结果表明:该竖井在开挖过程中底鼓的竖直位移最大值出现在开挖深度约为60 m处的低强度砂质泥岩,竖直位移最大值为12.99 mm;竖井开挖过程中侧壁变形在泥岩段明显大于砂岩段,侧壁变形的最大位移出现在开挖深度24 m的泥岩处,水平位移最大值为2.48mm。在泥岩和砂岩接触部位易出现应力集中,建议在泥岩和砂岩分界处和泥岩段的井壁提高永久支护的强度。研究结果对该矿竖井的开挖具有较重要的参考价值。

To counter the deformation and failure in shaft excavation process in a coal mine in Shanxi,and taking the hole inspection data of the coal mine as the geological background and 300 ～ 400 m underground rock stratum as the research object,3D simulation analysis on the shaft excavation process was made with application of FLAC3D software.The displacement and stress state of the shaft before and after each excavation step at 3 m were calculated to investigate the deformation law of shaft sidewall and bottom.The calculation results showed that the maximum vertical displacement of the shaft bottom heave that appeared at low-strength sandy mudstone with the excavation depth of 60 m was 12.99 mm.The sidewall deformation at mudstone section is larger than that at sandstone during the shaft excavation process and the maximum displacement of the sidewall that appeared at the excavation depth of 24 m was 2.48 mm in horizontal.Stress concentration easily appeared in the contact zone between mudstone and sandstone.Improving the strength of permanent support in mudstone and the boundary of sandstone and mudstone was recommended.These research results have important reference value for the mine shaft excavation.