Failure Behaviors of Rock Masses Around Highly Pressurized Cavern: Initiation and Modes of Failure

Reasonable failure path including the failure initiation location and propagation direction is essential in uplift
evaluation of highly pressurized caverns. This study investigates the failure initiation behavior of a rock mass
that encloses a highly pressurized cavern, taking into account the diverse strength properties of the rock mass. A series of stress analyses in conjunction with failure criteria were performed in the framework of a 2D axisymmetric model. The analysis results indicated that the initial mode of failure strongly depends on the rock strength properties, regardless of the initial stress condition. In contrast, the failure initiation location was influenced by both the rock strength properties and the initial stress condition. Diagnostic charts were proposed for determining the failure mode using the relationship between the tensile and shear strengths of the rock mass and for identifying the failure location using the appropriate parameters. Tests of a physical model with a 200-fold scaling-down, in which a digital image correlation technique is utilized to monitor the full-field displacement during the experiments and identify the failure mode, were also performed to verify the effectiveness of the proposed charts.