|
| Index | Rockburst stage | Stiffness condition |
| Weak stiffness | Strong stiffness |
|
| Event type by seismic energy | Development | The type of medium and large energy event is more, and the small energy event is less. | The type of medium, large energy event decreases, and the small-energy event increases. |
| Occurrence | Mixed large and small energy events. | The large energy event is dominant. |
|
| Daily high energy rate | Development | The daily high energy rate increases gradually. | The daily high energy rate increases gradually and higher than weak stiffness. |
| Occurrence | Daily high energy rate decreases. | Daily high energy rate decreases and lower than weak stiffness. |
|
| Cumulative moment magnitude per hour | Development | Increase of high moment magnitude. | Increase of high moment magnitude and the whole is higher than the weak stiffness. |
| Occurrence | The cumulative moment magnitude per hour decreased obviously. | The cumulative moment magnitude per hour decreased obviously, but lower than weak stiffness. |
|
| Cumulative microseismic source average displacement | Development | Slow growth | Rapid growth and sudden increase. |
| Occurrence | Slow growth | No significant changes. |
|
| Event type by apparent volume | Development | The type of small volume event is more, and the other types are less. | The type of small volume event decreases largely, and the medium volume event increases. |
| Occurrence | Mixed extremely-larege, large and small volume event. | The large volume event is dominant. |
| Site characteristics of rockburst | Rockburst occurs on the excavation surface or tunnel roof, and is controlled by a single or multiple sets of structural plane, which could cause initial support cracking and fall of ground. | Rockburst possesses the features of strong energy release and large affected range, which can trigger side wall heave, floor cracking or floor heave in the same tunnel or adjacent tunnel. |
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