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River valley terrain can lead to local amplification effects of site seismic responses and significant spatial variation of strong ground motions. This paper presented a semi-analytical solution for the scattering of incident plane P-waves by a saturated river valley with arbitrary shapes containing water, using the moment method and the wave function expansion method. The influence of factors such as valley geometry shapes, soil porosity, wave incident angle and frequency on the seismic response of valley topography is further investigated. Parameter analysis shows that these factors have a significant impact on the site seismic response. Soil porosity has a greater impact on the horizontal response of the site than on the vertical response. Moreover, the soil porosity is directly related to the amplitude of the pore pressure, while the incidence angle and frequency of the incident wave determine the distribution position of the pore pressure amplitude. This semi-analytical solution can be seen as an attempt to solve the scattering problem of incident P wave by saturated river valleys of arbitrary shapes containing water. The purpose of this paper is to provide a reference and a possible way for subsequent scholars to study the analytical solution to this problem. The conclusions drawn from the parameter analysis in this paper can also serve as a theoretical basis for seismic fortification in saturated valley areas. • Semi-analytical model for plane P waves scattering by saturated river valley with arbitrary shapes containing water. • Moment method is applied to obtain the semi-analytical solution to system response. • Influence of the water, medium porosity, and incident wave on ground surface displacement is investigated. [ABSTRACT FROM AUTHOR]

Sand liquefaction is one of the leading causes of severe earthquake damage. In this study, shaking table tests were carried out to investigate the dynamic interaction between the saturated sand and the irregular subway stations. In this test, a method for the preparation of a liquefiable foundation based on a flexible sensing chain combined with water sedimentation was proposed. Typical test results were interpreted, including the development and spatial distribution of pore pressure, surface subsidence, acceleration, deformation, and dynamic earth pressure. Results show that the spatial distribution of excess pore water pressure is changed by the irregular underground structure, and the liquefiable soil below the bottom plate of the structure can be divided into I, II, and III areas based on the degree of liquefication. The surface subsidence is significantly related to Arias intensity and is concentrated within the range of 5 %–95 % of the intensity. The structural floating is synchronized with the liquefaction of the saturated sand, and the uneven floating and inclination of the underground structure are remarkable, anti-flotation design of underground structures should take into account differences in section forms. During the liquefaction of saturated sand, the foundation soil has conspicuous lateral deformation, especially in the deep soil layer. The shape of the dynamic earth pressure increments turns from triangular to linear, when the foundation soil changes from non-liquefied to liquefied. Compared with the limiting values of the elastic inter-story drift ratio, the maximum inter-story drift ratio of the structure is smaller. The tensile strain responses on the columns, particularly in the lower layer, are more prominent than those at the slabs and side walls. • Shaking table model test is designed on the saturated sand-underground structure interaction system. • Dynamic interaction between irregular-section underground structures and saturated sand is researched, including the different liquefaction states for saturated sand. • A method for the preparation of a liquefiable foundation based on a flexible sensing chain combined with water sedimentation was proposed. • The liquefiable soil below the bottom plate of the structure can be divided into three areas based on the degree of liquefaction. • Differences in cross-section forms should be considered in the anti-floating design of underground structures. [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]