# Development of Rockburst Research: A Comprehensive Review
## 5 Rockburst Intensity Classification and Prediction  
### Empirical Criteria for Rockburst Intensity Classification and Prediction  
In the early stage of the construction, the empirical method is usually used to determine the rock mass quality and evaluate the risk of rockburst to provide empirical guidance for design and support. The empirical criterion is an index or criterion for judging the occurrence and strength of rockburst based on the summary of rockburst physical tests and engineering cases, which is divided into a single index criterion and comprehensive index criterion. The single index empirical criterion method is mainly based on stress/strength, brittleness, energy and depth, including the Turchaninov criterion [92], the [PERSON] criterion [93], the [PERSON] criterion [94], the [PERSON] criterion [95], the elastic energy index [96], the Tao criterion [97], the [PERSON] criterion [98], the potential stress failure index [99] and the peak energy impact index [100]. The index criteria proposed in recent years are shown in Table 4. The single index criterion is one-sided, which does not consider the influence of other factors on rockburst. The comprehensive index criterion considers the important control factors of rockburst and then establishes the corresponding mathematical model or system to evaluate rockburst. The excavation vulnerability potential (EVP), considering stress condition, ground support, portal span and geological structure, which was calibrated by using eighty case histories and 250 individual incidences of rockburst damage from underground hard rock metalliferous  
\begin{table}
\begin{tabular}{l l c c c c c} \hline \hline
**Researchers** & \multirow{2}{*}{**Index and/or Equations**} & **No** & **Light** & **Medium** & **Heavy** & **Serious** \\
**(Year)** & & **Rockburst** & **Rockburst** & **Rockburst** & **Rockburst** & **Rockburst** \\ \hline [PERSON] et al. (2011) [102] & RVI = _FsFrEnFg_ & \(\backslash\) & \(\backslash\) & \(\backslash\) & \(\backslash\) & \(\backslash\) \\ [PERSON] et al. (2011) [103] & Brittleness index \(B_{4}=(E_{u}-M)/M\) & \(\backslash\) & \(\backslash\) & \(\backslash\) & \(\backslash\) & \(\backslash\) \\ [PERSON] et al. (2012) [104] & BSR = \((\sigma 1-\sigma 3)/\sigma c\) & 0.35–0.45 & 0.45–0.6 & 0.6–0.7 & 0.7 & \(\backslash\) \\  
mines in Australia and Canada, is used for a vulnerability assessment of underground excavation for rockburst damage [112]. The rockburst vulnerability index (RVI), consisting of four control factors (stress _F_s, rock mass _Fr_, rock mass system stiffness _Fm_ and geological structure _F_g), was proposed to determine the risk level of rockburst via analyzing 62 rockburst cases in the chamber group of the Jinping II hydropower station. The RVI index can be used when rockburst case data, in situ stress conditions, engineering geological conditions, rock mechanical properties, rock mass structure and construction design are sufficient [102]. [PERSON] et al. found that the three variables maximum tangential stress of tunnel wall \(\sigma_{\theta}\), tensile strength \(\sigma_{t}\), and rock mass integrity coefficient \(K_{v}\) are relatively independent through an in situ geological survey, and then the authors proposed a comprehensive risk criterion of strain rockburst named rockburst potential \(P_{rb}\), which is based on experimental data [105]. [PERSON] et al. proposed a criterion named the rockburst proneness index (RPI) in combination with rock strength, the brittleness coefficient, the geological strength index (GSI), TBM excavation disturbance and in situ stress [110]. Considering a roadway's buried depth and rock hardness, [PERSON] et al. proposed a rockburst occurrence criterion based on stress and energy [111]. The comprehensive index criterion is mainly combined with in situ stress, inherent rock properties and geological information of surrounding rock. Compared with single index criterions, they have obvious advantages.