Microseismic Activity Characteristics of Surrounding Rock Under Shaft Excavation Disturbance at Yebatan Hydropower Station

The high geostress and complex geological structure of underground powerhouse at Yebatan Hydropower Station frequently result in surrounding rock failure which delay construction schedule. Based on the microseismic monitoring technique, activity characteristics is analyzed under excavation disturbance intersection area shaft 2# drainage gallery. results show that events are concentrated rock, cumulative energy stably increasing then rapidly increasing, apparent stress contour illustrates distribution concentration. evolution law index continuously maintaining a level, suddenly decreasing, last again volume increasing. In addition, it discusses mechanism rock. Finally, can provide important reference technical support for construction.