Application of Impact Imaging Method on Nondestructive Detection of Void Defects in Sandwich-Structured Immersed Tunnel

Figure 6

Schematic diagram of the measuring points layout on the compartment (unit: mm). (a) The top view of the compartment structure, (b) the grid layout of survey line, (c) the front view of compartment structure, and (d) schematic diagram of data collection.

(a)

(b)

(c)

(d)