Abstract: The stability of underground rock caverns is affected by the geomechanical properties their surrounding rock mass. This paper presents a stability evaluation of an underground rock cavern during the rock excavation for a hydropower generation station in western China. The evaluation considered various combination of structural geological conditions, rock mass property as well as initial geostress field conditions by using elastoplastic finite element analysis for different rock excavation sequences. The influence of different geological faults, rock properties and initial stress conditions on the deformation, stress and plastic zones in the cavern are discussed. The results can be used for the design and construction of underground rock cavern under similar conditions.

Key words: under ground rock caverns, numerical simulations, geomechanical conditions, stability of rock mass