The Method of Determining Excavation Damaged Zone by Acoustic Test and the Application in Engineering Cases
Table 1
Typical V-L curves according to the results of practical engineering test.
No
Curve
Description
(a)
The wave velocity V of rock mass near the orifice is very small. With the increase of hole length L, the wave velocity of rock mass increases rapidly, and then the growth rate slows down and gradually tends to be stable.
(b)
The wave velocity of rock mass can be divided into three distinct stages. Stage I is relatively low near the orifice. With the increase of hole length L, the wave velocity in stage II increases and then decreases within a certain range, and then the wave velocity gradually tends to be stable in stage III.
(c)
The wave velocity of rock mass also can be divided into three stages: stage I is near the orifice, and there are many wave peaks and troughs; the maximum wave peak appears in stage II, and stage III is that after the last wave peak far away from the orifice. The rock wave velocity gradually decreases and tends to be stable.
