Finite Element Seismic Analysis of Cylindrical Tunnel in Sandy Soils with Consideration of Soil-Tunnel Interaction

摘要

Distribution of Seismic waves from the bedrock through the soil layers can cause severe damages not only to structures on the soil surface but also to subsurface structures. Previous studies have indicated significant role of site condition in modifying and changing the characteristics of the strong ground motion data. This paper presents an idealized two dimensional plain strain finite element seismic soil-tunnel interaction analysis using ABAQUS v.6.8 program. The analysis performed by considering three actual ground motion records representing seismic motions with low, intermediate and high frequency content. Two different sandy soils (dense and loose sand) have been modelled. In order to consider the effect of soil-tunnel interaction, all of the analysis was performed for free field (without tunnel) and compared with models including tunnel. Influence of different subsoil's (dense and loose sand) in each actual ground motion record has been investigated on amplification, acceleration response and stress and strain propagation on the soil-tunnel interface. Results illustrate that existence of tunnel amplifies the seismic waves on the soil surface and the maximum amplification occurs on the interface of the tunnel and soil.