Simulation and analysis of excavation of variable cross-section cavern with advanced support

The stability of excavating the variable cross-sections cavern is one of the important research topics about the underground engineering. Particularly for weak surrounding rockmass, it may bring insecurity and instability to excavate the cavern from the small sectional-section to the big. By means of the numerical analysis of finite difference, the stability of excavating variable cross-sections cavern was studied; and effects of two construction methods about the advanced support using the ductule grouting or without the advanced support on the engineering were analyzed. The results showed that it's more unstable when excavating the cavern from the small cross-section to the big; and the advanced support can considerably improve the stability of the surrounding rocks and reduce the deformation of the cavern, and also avoid the collapse of cavern excavating in weak rock. The results are the some meanings for the construction of similar caverns.