Stress and Deformation Characteristics of Tunnel Surrounding Rock under Alteration

Based on a typical project in an altered rock area, this study carried out numerical simulations using the FLAC3D software to calculate changes stress field, deformation and plastic zone of surrounding during unsupported supported excavation water transfer tunnel. The degree alteration was considered as base point. following results were obtained: state, tunnel affected by different degrees alteration, compressive concentration appeared within certain range at bottom chamber. value all-directional decreased with deepening while opposite case for depth influence. displacement side walls chamber large increased significantly alteration; monitoring points distributed around exhibited same trend. obviously expanded deepened. stress, effectively controlled after adoption support measures. obtained can be used reference similar projects areas.