关键词: 隧道工程, 地铁车站, PBA工法, 数值模拟, 扣拱顺序

Abstract: One metro station by PBA method undercrossed the top bridge, and the three bridge piles above the station were only 0.6m away from the top of the station. Reasonable buckle-arch construction sequence was the key for pile settlement controlling. 3D finite element method midas was used to analyze the variation law of pile displacement, surface subsidence and middle-column displacement under different buckle-arch sequence and different staggered distance between middle span and side span. The research results show that: the middle-column displacement with middle before side span sequence is larger than that with side before middle span sequence, and the pile displacement and surface subsidence can be effectively controlled; taking the three bridge piles closest to the station as the zero point, the transverse influence range of the buckle-arch construction on the bridge piles is about 15m; under the four construction schemes, the maximum differential settlement of bridge piles is basically the same, and the change trend is consistent with the buckle-arch construction step; the absolute settlement and differential settlement of bridge pile caused by buckle-arch construction are within the allowable range, and the upper bridge is in a safe and controllable state; the pile settlement, surface settlement and middle-column displacement of the three-section model with the staggered distance between the middle span and the side span are better than those of the six-section model. After comprehensive comparison and selection, it is suggested that the buckle-arch construction sequence should be middle before the side span, and the staggered distance between the excavation faces of the middle span and the side span should be three-section mode.

Key words: tunnel engineering, metro station, PBA method, numerical simulation, buckle-arch sequence