Abstract: During subway operation, the soil strata where the tunnel is located continue to experience settlement, and the dynamic load of trains is an important factor that cannot be ignored. To study the settlement pattern of soft soils under train load, a three-dimensional numerical model was established using the finite element software ABAQUS, combined with a section tunnel in Hangzhou that has already been laid but not yet in operation. The influence of different train speeds and tunnel depths on the soft soil layer was analyzed, and a settlement control and reinforcement measure was proposed. The research results indicate that for the same tunnel depth, the higher the train speed, the shorter the time the subway operates at the same node. The earlier the node reaches the maximum vertical displacement, but the smaller the vertical displacement it reaches; At the same train speed, the settlement of the soil beneath the tunnel decreases as the depth of the analysis point increases; At the same train speed, the deeper the tunnel is buried, the smaller the settlement of the tunnel arch bottom; The maximum settlement of the arch bottom of the reinforced tunnel under a single train load is 1.37 mm, with a controlled settlement ratio of 19.9%. The cumulative settlement of the subway after 20 years of operation is predicted, and the settlement of the reinforced tunnel is significantly reduced.

Key words: Train Load, Long Term Settlement, Reinforcement Inside the Tunnel, Numerical Simulation, MJS Constructed Piles