Influence And Control Of Metro Tunneling By Drift-PBA Method On Adjacent Bridge Piles

Construction of urban metro is inevitably restricted by existing environments, and many metros are built along city roads, running through pile foundations of the overpasses. Metro tunneling is certain to disturb ambient ground, and it may cause settlements or differential settlements of adjacent piles in certain range, which, if excessive, would affect the normal operation and safety of the overpass.Research of this paper is carried out closely combined with Guomao subway station, which has many construction difficulties and risks in Beijing Metro Line 10. Focus on main theoretical problems encountered during construction, the influence of metro tunneling by Drift-Pile-Beam-Arch(Drift-PBA) method on adjacent piles is studied from three-dimensional effect, time effect and probability analysis of differential settlements of adjacent piles respectively, and some control measures for metro tunneling adjacent piles are put forward.Influence regularities of four construction stages including tunneling and supporting of headings, construction of border piles, crown beams and arch springing and backfill of headings, tunneling and supporting of main tunnel and permanent liner of main tunnel on ground settlements are studied by numerical simulation method and field measurement, and the responses of adjacent foundation piles induced by tunneling by Drift-PBA method are systematically researched from settlement, lateral deflection, axial force, bending moment and pile-soil interaction of piles.On the basis of triaxial rheological test research of adjacent soil of Guomao subway station, viscoplastic model parameters of strata which have theological property are obtained. Data file of three-dimensional time effect analysis is programmed based on FLAC3D code, and variation regularities of ground and pile foundation settlements induced by metro tunneling with time are studied, which provide evidences for prediction of construction influence and selection of short piles reinforcement measures of Guomao subway station.In order to get the possible range of differential settlements of adjacent pile foundations induced by metro tunneling by Drift-PBA method, probability analysis theory is introduced, based on ANSYS finite element method, APDL code is programmed, and probability analysis is conducted to study the differential settlements of adjacent pile foundations induced by metro tunneling by Drift-PBA method,...