Performance of Super-Large-Span Tunnel Portal Excavated by Upper Bench CD Method Based on Field Monitoring and Numerical Modeling

Table 4

Field monitoring sections.

Lining type	Construction method	Stress monitoring section	Deformation monitoring section	Burial depth (m)	Clear distance (m)	Lithology	Number of buried elements
Shallow burial with grade V in tunnel portal	Upper bench CD method	YK2 + 133	YK2 + 125; YK2 + 133; YK2 + 140	48	13.5	Residual soil	120