Construction scheme of foundation pit excavation and steel pipe support for a subway station in Beijing
**The station is located at the intersection of * * Road (planned) and * * West Road, along the east-west direction of * * Road. The northeast quadrant of the intersection is * * ground floor residential area; The northwest quadrant is the 24 storey * * Building; The southwest quadrant is the * * telephone office on the 10th floor; The southeast quadrant is a 13 storey * * service center building. The east and west station halls of the station adopt the rectangular frame structure of double columns, three floors and three spans, which is constructed by open excavation method and supported by piles. The east station hall is located at the east side of * * West Road. The foundation pit is 26.785m deep, 86.9m long, and the roof overburden thickness is about 4.8m; The west station hall is located in the west. The foundation pit is 26.467m deep, 85.5m long, and the roof overburden thickness is about 4.5m-4.7m. The enclosure structure of the open cut main body of the west station hall station is divided into shield section (axis 1-3), standard section (axis 3-10) and widening section (axis 10-11); The enclosure structure of the open cut main body of East Station Hall Station is divided into shaft section (12~13 axes), standard section (13~21 axes) and shield section (21~23 axes). The foundation pits of East and West Stations are supported by piles, and Ф 1000 @ 1500mm (1400mm) bored cast-in-place piles are used. C20 concrete shall be sprayed between piles, and C30 concrete shall be used for enclosure pile body concrete. There are 321 retaining piles for the main structure of the east and west station halls. The safety level of the side wall of the foundation pit is Level I, the protection level of the foundation pit deformation control is Level I, the maximum ground settlement is ≤ 0.15% H and ≤ 30mm, and the maximum horizontal displacement of the retaining structure is ≤ 0.2% H and ≤ 30mm. During design calculation, the absolute elevation of the ground is calculated as 39.800mm of the maximum elevation after site leveling. Four supports (two φ 609mm steel supports and two φ 800mm steel supports) are used for the standard section of the enclosure structure of the east and west station halls, with a pile length of 30.55m; The shield section adopts four supports (reinforced concrete support, one φ 609mm steel support, two φ 800mm steel support)+one backstop (φ 609mm steel support), with a pile length of 32.6m; Five supports (three reinforced concrete supports, one φ 609mm steel support, and one φ 800mm steel support) are used for the shaft section (widened section). Since the shaft section (widened section) is close to the main body of the excavation section that has been completed, the pile length is not equal.
![[Beijing] A complete set of structural cad design drawings of a subway station - Figure 1](https://fd.co188.com/group1/M02/0E/3E/rBBhIF_aCXmAGabqAAApjY2PV-Y981-1.jpg!610c.jpg "[Beijing] A complete set of structural cad design drawings of a subway station - Figure 1")
![[Beijing] A complete set of structural cad design drawings of a subway station - Figure 2](https://fd.co188.com/group1/M02/0E/3E/rBBhIF_aCXmAGabqAAApjY2PV-Y981-2.jpg!610c.jpg "[Beijing] A complete set of structural cad design drawings of a subway station - Figure 2")
