Numerical study study on the response of ground movements to construction activities of a metro station using the pile-beam-arch method

This paper aims to investigate the issues associated with the pile-beam-arch method for construction of metro stations. First, a detailed description of the procedures involved in the construction of a metro station is given. Secondly, a three-dimensional numerical model is established by FLAC(3D) to simulate the main construction process in practice, which consists of three phases, the excavation of the pilot tunnels, the installation of the load-bearing system, and the removal of the soil inside the metro station. These phases are then divided into fifteen construction steps, at the end of which the resulting ground surface settlements are recorded and analyzed. Numerical results reveal that the resulting displacements can be divided into four categories, the tunneling-induced settlement, the settlement occurs in response to an increase in vertical pressure, the tunneling-induced settlement in the presence of the load-bearing system, and the settlement occurs in response to a decrease in vertical pressure. Thirdly, the effects of settlement control measures are evaluated and discussed. Lastly, the comparison between the simulated and observed ground surface settlements collected from the existing literature are used to illustrate the effects of dewatering and the construction of working shafts and connecting tunnels.