Research Article
Experimental Research and Numerical Simulation on Grouting Quality of Shield Tunnel Based on Impact Echo Method
Table 3
Theoretical peak frequencies.
| | Specimen number | (Hz) | (Hz) | (Hz) |
| | SG-A-DE | 6271 | 4908 | 3256 | | SG-A-ND | 6271 | — | 3256 | | SG-B-DE | 6271 | 5311 | 3413 | | SG-B-ND | 6271 | — | 3413 | | SG-C-DE | 6271 | 5489 | 4253 | | SG-C-ND | 6271 | — | 4253 |
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