LAUSR

ABSTRACT The investigation of the dynamic response of the tunnels and structures under the acting of train vibrating load is significant for subway tunnels. In this paper, the intersection of Line 4 of Tehran subway with Tohid Tunnel is investigated using numerical modelling. Because these tunnels are excavated in the soil, the model is considered as a continuum condition, and a 3D model generated based on the finite difference method. In this research, the dynamic load of the train is applied at Line 4, and particle velocity on the ground recorded in three vertical sections, in the perpendicular direction to Line 4. The results show that the measured peak ground velocity is 1.75 mm/s more than the allowable value. So, to reduce the vibration level, it is better to use light waggons. If the weight of waggons with the passenger be less than 29.4 tonnes, the level of particle velocity will be less than 2.5 mm/s.