Novel Excavation and Construction Method for a Deep Shaft Excavation in Ultrathick Aquifers

Table 2

Construction schedule for the excavation.

Stage	Construction activities	Period (month/day/year)
S1	Excavation to 2.5 m BGS (soil layer 1) and bracing struts at 1.4 m BGS (level 1)	08/23/2016–08/27/2016
S2	Dewatering excavation to 7.8 m BGS (soil layer 2) and bracing struts at 6.5 m BGS (level 2)	08/28/2016–09/10/2016
S3	Dewatering excavation to 12.9 m BGS (soil layer 3) and bracing struts at 11.7 m BGS (level 3)	09/11/2016–09/26/2016
S4	Dewatering excavation to 18.1 m BGS (soil layer 4) and bracing struts at 16.9 m BGS (level 4)	09/27/2016–10/13/2016
S5	Dewatering excavation to 23.6 m BGS (soil layer 5) and bracing struts at 23.6 m BGS (level 5)	10/14/2016–11/08/2016
S6	Underwater excavation without drainage to 41.6 m BGS	11/09/2016–12/31/2016
S7	Underwater bottom-sealing concrete construction	01/01/2017–01/06/2017
S8	Filled concrete construction	01/07/2017–01/10/2017
S9	Casting of the base slabs	01/11/2017–01/24/2017