Dynamic Analysis of SSI Effects on Underground Structures

This paper describes the Dynamic Soil-Structure Interaction (SSI) effects on the underground structures. The finite element model for Nuclear Power Plant (NPP) and a tunnel was considered to analyze the effects of SSI. Dynamic analysis was carried out considering three transmitting boundary conditions. The effect of embedment for NPP founded on soft soil and seismic responses of a reinforced concrete building in proximity with an underground circular tunnel were studied. The lateral spacing of the circular tunnel from the center line of the building was varied while maintaining a constant depth below the ground level. The effect of embedment has been investigated and the result shows acceleration and displacement responses of the system are smaller with the infinite boundary as compared to viscous and kelvin boundary conditions. In tunnel analysis, the results shows maximum building response occurs when the tunnel is positioned directly below the centre line of the building.