Continuum analysis of the structurally controlled displacements for large-scale underground caverns in bedded rock masses

• Published in: Tunnelling and underground space technology 2020-03, Vol.97, p.103288, Article 103288
• Main Authors: Li, Ang, Liu, Yi, Dai, Feng, Liu, Ke, Wei, Mingdong
• Format: Article
• Language: English
• Subjects: Bedded rock mass; Caverns; Continuum modeling; Damage assessment; Damage model; Deformation; Displacement; Excavation; Microseismic monitoring; Microseisms; Rock masses; Rocks; Strata; Structural damage; Structurally controlled displacement; Three dimensional models; Underground cavern; Underground caverns; Underground construction
• ISSN: 0886-7798; 1878-4364
• DOI: 10.1016/j.tust.2020.103288

•A damage model based on microseismic data is developed.•Structurally-controlled displacements are predicted in 3D continuum framework.•Geological structures in numerical model can be specifically ignored.•Reasonable scope of potential failure region is revealed. Large displacements controlled by the motion of layered rock strata usually pose a high hazard to the stability of high sidewalls of the underground caverns in bedded rock mass. Timely and accurate prediction of structurally controlled displacement can provide more reasonable guidelines for supporting measures during cavern excavation. In this study, an approach integrating the continuum modeling and microseismic (MS) monitoring data, was proposed to quantitatively predict the structurally controlled displacements in bedded rock masses surrounding large-scale underground caverns. First, a comprehensive method based on the MS data was adopted for judging the fracture type of bedded rock mass, and this method was validated by field surveys. Second, the damage scope of the bedded rock mass caused by each MS event was determined on the basis of fracture types. A damage model based on the MS data was successfully developed to be embedded into three-dimensional continuum modeling. Finally, our proposed method was verified by comparing its predictions with the actual data. Good agreements indicated that the large deformations induced by the rotation of layered rock strata with long deformed length, can be fully predicted using the damage model. Complicated geological structures can even be ignored when establishing the three-dimensional continuum model. The reasonable scope of potential failure region can be revealed by the predicted deformation mode, which verified the damage scope corresponding to each MS event.