Assessment of the Excavation Damaged Zones in the Surrounding Rock of an Underground Powerhouse under High In Situ Stress Using an Acoustic Velocity Detecting Method

Figure 13

Typical test results of acoustic wave curves measured in the upstream sidewall of the main powerhouse during excavation (a) in section of 0 + 041.3 m (elevation of 1718.00 m) and (b) in section of 0 + 008.8 m (elevation of 1718.00 m).

(a)

(b)