Stability Analysis of Surrounding Rock of an Underground Cavern Group and Excavation Scheme Optimization: Based on an Optimized DDARF Method

The surrounding rock stability of an underground cavern group is important issue in the process excavation, which has characteristics large displacement, discontinuity and uneven deformation, so calculation analysis are very complicated. optimized discontinuous deformation for failure method was adopted to analyze a real engineering under different excavation schemes. cracking schemes, depth crack expansion vertical displacement arch bottom floor were obtained, following conclusions drawn: (a) After completion problems mainly appeared rocks arch, left wall, right wall main powerhouse, transformer chamber tailrace surge tank. (b) Fault f2 influence on tank, while fault f1 no cave group. (c) scheme simultaneous three caverns shows advantages propagation displacements caverns.