Study on the Correlation of Vibration Properties and Crack Index in the Health Assessment of Tunnel Lining

Table 1

The basic conditions of the concrete lining for ten studied spans.

Span number	Lining thickness	Inverted arch	Buried depth	Surrounding rock type
1	0.70 m	Yes	3 m	Sandstone
12	0.55 m	No	25 m	Sand tuff
16	0.55 m	No	25 m	Sand tuff
18	0.55 m	No	25 m	Sand tuff
20	0.55 m	No	25 m	Lapilli tuff
35	0.70 m	No	23 m	Basalt
42	0.55 m	No	23 m	Basalt
49	0.55 m	No	23 m	Tuff breccia
58	0.70 m	No	23 m	Lapilli tuff
65	0.70 m	Yes	0 m	Lapilli tuff