Rock Burst Criterion Based on Elastic Strain Energy Density Gradient and Energy-Release Space

Deeply buried tunnels are often accompanied by high in situ stress, and rock burst is a common geological disaster during excavation in hard rock. This paper proposes a new rock burst discrimination criterion that is based on actual engineering and tests as well as the energy-release mechanism during a rock burst occurrence. By considering the elastic strain energy density gradient and the energy-release space together, the proposed criterion establishes a novel rock burst discrimination value, W. In addition, the elastic strain energy density gradient within isotropic surrounding rock is calculated using an improved complex variable function method. Rock burst discrimination calculation is performed for cases including both circular and noncircular tunnels. The results show that the rock burst risk decreases as the discriminant value W decreases, and that when W falls below the critical value (Wcr = 1), the surrounding rock ceases to experience rock burst failure. A comparative analysis with an existing rock burst discrimination criterion reveals that the proposed criterion exhibits better discrimination accuracy.