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Segmented tunnels are widely used nowadays. However, most existing studies on the seismic response of underground tunnels are based on the model of continuous linings, without considering the segment joints. This paper presents a numerical study aiming to investigate the factors that affect the seismic response of segmented tunnels, with a step further than previously, considering obliquely incident seismic waves. The numerical simulation is carried out by a 2.5D coupled finite element-boundary element (FE-BE) model, which can properly simulate the soil-tunnel interaction for obliquely incident seismic waves and predicts both the transverse and longitudinal seismic responses of the tunnel. It is shown that the joint distribution is one of the critical factors that determine the seismic responses of the segmented tunnel, and the influence of the segment joints tends to be more pronounced when they are located near the positions of large transverse bending moments in the tunnel lining. Compared with the homogeneous tunnel, the reduction in the transverse bending moment and axial force of the segmented tunnel is significant, while it is minor in the longitudinal bending moment and axial force, and the effect of the segment joints highly depends on the soil-tunnel relative stiffness. In addition, the influence of the spectral characteristics of the input motions on the tunnel responses is highlighted. • Dynamic soil-segmented tunnel interaction for 3D obliquely incident seismic waves. • The segment joints lead to smaller tunnel internal forces while larger deformations. • The effects of the segment joints on the tunnel longitudinal internal forces are small. • The effects of the segment joints highly depend the soil-tunnel relative stiffness. • Input motions with significant long-period spectral accelerations cause large tunnel responses. [ABSTRACT FROM AUTHOR]

The seismic performance of liquefied natural gas (LNG) tanks is significantly influenced by Soil-Foundation-Structure Interaction (SFSI). It is essential to investigate the effect of the SFSI on isolated LNG tank, particularly on a deep soil site. This study aims to examine the impact of the SFSI on the seismic performance of an isolated LNG tank located on the deep soil site. The impact of foundation type, pile length, and the frequency content on the primary seismic responses of the LNG tank were thoroughly examined in this study. These seismic responses include the acceleration of the outer tank, the height of the sloshing wave, and the shear force and bending moment of the inner tank. Additionally, the seismic force along the pile foundation, such as shear force, lateral displacement, and bending moment, was also analyzed. The results indicate that for isolated LNG tanks, it would be dangerous without considering the SFSI, while for the pile foundation, it may be beneficial when considering the SFSI. The pile foundation types did not considerably affect the seismic response of the isolated LNG tank in the deep soil site. Additionally, the seismic response appears to be highly sensitive to the frequency characteristics of the seismic excitation, especially the low-frequency content. • The impact of SFSI on the seismic performance of an isolated LNG tank located on the deep soil site was researched. • The pile foundation types, and the frequency domain of seismic excitation were assessed. • Comprehensive modeling technology was used. [ABSTRACT FROM AUTHOR]