Study on Disease Mechanism and Theoretical Quantification Method of Tunnel Structure

Table 8

Standard for condition evaluation of lining thickness and cavity.

Status value	Technical status description
0	The thickness of the lining meets the design requirements, and there is no void behind it
1	There is a gap behind the sidewall or vault, but there is no possibility of expansion
2	There is a gap behind the sidewall lining, which may expand
3	The concrete may fall, there is a large hollow on the back of the arch, and the upper tribal stone can fall to the arch back; the lining structure invades the inner contour boundary
4	There is a large cavity on the back of the lining arch, and the effective thickness of the lining is very thin. The upper part of the cavity may fall to the arch back; the lining structure invades the building boundary