Influences of metro operation on ground vibration along Tianjin Z2 line

The Z2 metro line in Tianjin Binhai New Area is a new type of metro line. It has the characteristics of fast train operation and high frequency of departure. Its maximum speed of metro operation can reach 120 km per hour. At present, the speed of ordinary metro trains running in cities in China is generally 60~80 km per hour. Compared with the ordinary train load, the load of high-speed metro train has the characteristics of high frequency and large amplitude, and the pattern of environmental vibration is also different. Taking the first phase of Tianjin Z2 metro line as an example, and relying on the actual engineering data, a three-dimensional finite element model for rail track-tunnel-soil is established by using ABAQUS, a large-scale general finite element software. The dynamic implicit analysis is used to simulate the attenuation pattern of ground vibration intensity under the load of high-speed moving subway train in foundation soil, and different shield tunnels are compared. The variation of ground vibration under different conditions of road burial depth, train speed and soil properties of tunnels is studied. Combined with the relevant evaluation criteria for urban environmental vibration, the environmental vibration caused by metro is evaluated. The variation of environmental vibration protection distance of metro lines with the above three factors is preliminarily obtained. The research conclusions can provide some guidance for the selection of high-speed metro line construction, vibration prediction along the operation line and planning along the metro line in the future.