Analysis Of Time Effect Of Metro Tunneling With Drift-Pile Method On Adjacent Bridge Piles

With the development of national economic and urbanization, the construction of subway is developed cosmically. However, sometimes the subway constructions are restricted due to the limitation of line and space. Thereby quantities of special engineering problems may appear in practice. The problem of shallow excavation traversing the foundations of superstructure is one of the typical instances.The Guomao station of Beijing subway No.10 line traverses several bridge pile foundations. The excavation can cause ground settlement and variation of stresses, which will hurt the regular service of the existing bridge in the aspects such as pile foundation settlement, superstructure deformation, etc. Oversize deformation can endanger the normal function of the structures. Abundance data derived from practical supervisions and measures show that, there is obvious time effect on the surrounding ground, structure and establishments in excavation due to the rheological property of rock. As a result, the rheological characteristics and time effect should be considered.Aim at these problems, relative researches are conducted as following:1) Creep tests are conducted on the soil of typical ground around Guomao subway station to analyze the rheological and strength characteristics.2) The test data are fitted using the Generalized Kelvin Model, Power-function Model, and Burgers Model. By comparing the fitting results with the tests data, a proper constitutive model is adopted for numerical simulation, model parameters are given as well.3) Using the Kelvin viscoplasticity Model, a Tunnel-abutment-soil numerical model is created to study the time effect of metro tunneling with drift-pile method on adjacent bridge piles. The calculation result is approximate to the actual measurement.4) Some advice on the bridge piles deformation control is proposed for Guomao station.