Stability of a Rock Tunnel Passing through Talus-Like Formations: A Case Study in Southwestern China

Table 2

Measurement items for mechanical characteristics of the primary lining.

		Measurement items
		Surrounding rock pressure	Steel arch stress	Primary lining deformation
Monitoring section	Z5K64 + 500	✓	✓	✓
	Z5K64 + 540	✓	—	✓
	Every 5 m	—	—	✓
Instrument		Vibrating wire pressure transducer	Vibrating wire stress transducer	Total station
Monitoring frequency		1 time/day	1 time/day	2 times/day

Note: the primary lining deformation was measured twice a day at 8 am and 6 pm, whereas the surrounding rock pressure and steel arch stress were measured once a day at 6 pm. Therefore, the monitoring data in the following used the data recorded at 6 pm.