Evaluation of Reduction Methods of Vibrations Induced by Underground Railway on Surface Structures

Due to the growing development of subway, reduction methods of propagated vibrations in ground and reduction of its disturbances in urban areas is of particular importance. In this study, besides modeling of building foundation, load of floors, subway tunnel and surrounding soil, the filled trench in distance of 10 m from tunnel center and wave impedance block under building foundation have been evaluated as two methods for vibration reduction. Also effect of building weight in amount of receiving vibrations has been studied for buildings with 1, 5 and 10 floors. First, a proper modeling of the problem and boundary conditions in wave propagation has been examined. Then for FLAC software validation, maximum acceleration attenuation of train at the ground level has been compared with data of Motamed et al. model (2010) that has been done with ABAQUS software. Finally effect of building weight and two parameters of filled trench and wave impedance block included of thickness and shear wave velocity in reduction of vibration on surface structures have been studied as numerical modeling by FLAC 5.0 software. The results shows that with increasing building weight, amount of received vibrations in foundation reduce due to increasing of stress level under building. In addition, with increasing shear wave velocity and thickness barriers increase rate of vibration reduction so that parameter of shear wave velocity in filled trench and thickness parameter in wave impedance block act more effective.