Analysis on Deformation and Stress Characteristics of a Multibraced Pit-in-Pit Excavation in a Subway Transfer Station

Table 3

Construction sequence for the finite element analysis.

Stage	Construction details	Day
Before excavation
I	Construction of diaphragm wall	2018/08/01
External excavation
II-1	Excavation to 1.9 m below ground surface
II-2	Installing prop 1 at 1.4 m below ground surface	10/23
II-3	Excavation on the east-west sides to 8.1 m below ground surface
II-4	Install prop 2 on the east-west side at 7.6 m below ground surface
II-5	Excavation on the east-west sides to 13.7 m below ground surface
II-6	Installing prop 3 on the east-west side at 13.2 m below ground surface
II-7	Excavation on the east-west sides to 16.9 m below ground surface (reaching the bottom of outer excavation)
III-1	Excavation at the intersection to 8.1 m below ground surface
III-2	Installing the prop 2 at the intersection at 7.6 m below ground surface	12/10
III-3	Excavation at the intersection to 13.7 m below ground surface
III-4	Installing the prop 3 at the intersection at 13.2 m below ground surface	2019/01/20
III-5	Excavation at the intersection to 16.9 m below ground surface (reaching the bottom of outer excavation)	02/05
Internal excavation
IV-1	Excavation at the intersection to 18.2 m below ground surface
IV-2	Installing the prop 4 at the intersection at 17.7 m below ground surface	02/15
IV-3	Excavation at the intersection to 22.4 m below ground surface
IV-4	Installing the prop 5 at the intersection at 21.9 m below ground surface	03/13
IV-5	Excavation at the intersection to 25.8 m below ground surface (reaching the bottom of inner excavation)	04/10