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

<div>Four types of acoustic wave curves of the surrounding rock mass in the underground powerhouse of the Houziyan hydropower project: (a) type I (b) type II, (c) type III, and (d) type IV.</div>

Advances in Civil Engineering

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Figure 12

Figure 12: 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 12 | 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 