Abstract: A method for constructing a large-span station by two-wing open type semi-covered excavation and semi-reverse construction, is divided into three stages of excavation. First, excavate a first-stage inner small foundation pit, then excavate a second-stage annular foundation pit within the first-stage retaining piles and outside the range of the first-stage inner small foundation pit, and finally excavate a third-stage semi-covered excavation foundation pit below the first-stage inner small foundation pit and the second-stage annular foundation pit. By setting graded retaining piles, middle upright post piles, middle top plates, local waist beams and local concrete supports in the soil-rock combination strata, so that the force transfer between the foundation pit enclosure and the station main body structures and the underlying rock layer is clear and reliable, and a stable frame structure is achieved.

Abstract: A method for constructing a large-span station by two-wing open type semi-covered excavation and semi-reverse construction, is divided into three stages of excavation. First, excavate a first-stage inner small foundation pit, then excavate a second-stage annular foundation pit within the first-stage retaining piles and outside the range of the first-stage inner small foundation pit, and finally excavate a third-stage semi-covered excavation foundation pit below the first-stage inner small foundation pit and the second-stage annular foundation pit. By setting graded retaining piles, middle upright post piles, middle top plates, local waist beams and local concrete supports in the soil-rock combination strata, so that the force transfer between the foundation pit enclosure and the station main body structures and the underlying rock layer is clear and reliable, and a stable frame structure is achieved.

Abstract: Combination of an open and a hidden excavation for constructing a vertical orthogonal top exhausting air duct structure of a deeply-buried subway station is provided. Four horizontal air ducts: left and right piston air ducts, an exhaust air duct, and a fresh air duct are thrown out of the underground, respectively, leading to left and right piston air shafts, an exhaust air shaft, a fresh air shaft, and an entrance/exit of fire-fighting. The fourth underground floor is communicated with the hall floor of the station main body, and the fifth underground floor is communicated with the running tunnel and the platform floor of the station main body. During operation, the train will enter and exit the station through the fifth underground floor of the air duct, and the piston air and heat will enter the four transverse air ducts through the air duct main body.