The seismic response of tunnels in liquefiable ground requires careful consideration of adjacent structures due to potential structure-soil-structure interaction (SSSI) effects. These interactions can significantly influence the behaviour of underground systems during earthquakes, potentially affecting structural integrity and safety. This study aims at explore the interaction effect of a large diameter shield tunnel and a shallow-buried station with rectangular under seismic motion in liquefiable ground. For this purpose, 1 g shaking table tests of model SSSI system is designed. The model shield tunnel was manufactured with segments and joints using plexiglass, while the model rectangular station was precast using concrete embedded at a shallow layer adjacent to the tunnel. The responses of excess pore water pressure (EPWP), acceleration, displacement of the foundation in SSSI system and deformation of shield tunnel were measured and analysed in detail. The influence of relative stiffness of different structures is discussed based on finite element method. The experimental results show that the SSSI system exhibited a certain nonlinearity and plastic damage under input motions. Shear stress from two sides of the model structures caused the soil to dilate, resulting in a reduced EPWPR build-up between the two structures. Attenuation of the high-frequency components in the seismic wave was also observed in the soil between two structures. The tunnel structure exhibited a vertical stretching deformation at around 15 degrees angle from the vertical direction. The soil beneath the station has compensated for the soil loss caused by the uplift of the model tunnel during the process of tunnel uplift under input motion with high GPA. These new findings in the case of SSSI is helpful for the design and construction of underground structures.

The faster growth of urban areas, coupled with limited available land, has resulted in the development of densely packed buildings sharing common soil media. This proximity increases soil stress, influencing the deformation characteristics of nearby footings. Hence, there is a need to investigate the effect of structure-soil-structure interaction (SSSI) on the footing settlement. The aim of the study is to investigate the effect of SSSI on the footing settlement of a three-story symmetrical RCC building due to the presence of adjacent building with various height. The vertical and differential settlement of footings obtained from SSSI and soil-structure interaction (SSI) analyses are compared by using the finite element software ANSYS under gravity loading. The findings reveal that SSSI substantially amplifies vertical settlement in footings proximate to adjacent structures compared to SSI analysis, consequently inducing significant changes in differential settlement patterns between footings.

Rapid urbanization and land scarcity lead to the construction of multiple structures in proximity, supported on common soil media. This proximity increases soil stress, influencing the deformation characteristics of nearby footings. Hence, there is a need to investigate the effect of structure-soil-structure interaction (SSSI) on the footing settlement. In the present study, the effect of SSSI on the footing settlement of a three-storey building is investigated due to the presence of similar adjacent buildings arranged in various patterns (single adjacent building, side-by-side, L-shape, and inverted T-shape). The various interaction analyses are performed using finite element software ANSYS under gravity loading. The vertical and differential settlement of footings obtained from soil-structure interaction (SSI) and SSSI analyses are compared to evaluate the effect of SSSI under various adjacent building arrangements. The results indicate that in SSI case, inner footings show greater settlement compared to peripheral footings which causes high value of differential settlement between peripheral footings and those immediately adjacent to them. However, the presence of an adjacent structure in SSSI cases provides higher settlement in adjacent footings, which in turn reduces the differential settlement in these footings. Moreover, the SSSI effect on vertical settlement in SSSI (L-shaped) and SSSI (inverted T-shaped) is found to be more in corner footing located near to the adjacent buildings due to overlapping of soil stresses from two sides. The study quantifies the extent of settlement increase in various SSSI cases compared to SSI case, contributing valuable insights to mitigating potential settlement issues in densely developed areas.

Geo-materials naturally display a certain degree of anisotropy due to various effects such as deposition. Besides, they are often two-phase materials with a solid skeleton and voids filled with water, and commonly known as poroelastic materials. In the past, despite numerous studies investigating the vibrations of strip foundations, dynamic impedance functions for multiple strip footings bonded to the surface of a multi-layered transversely isotropic poroelastic half-plane have never been reported in the literature. They are first presented in this paper. All strip foundations are assumed to be rigid, fully permeable, and subjected to three types of time-harmonic loadings. The dynamic interaction problem is investigated by using an exact stiffness matrix method and a discretization technique. The flexibility equations are established by enforcing the appropriate rigid body displacement boundary conditions at each footing-layered soil interface. Numerical results for dynamic impedance functions of two-strip system are presented to illustrate the influence of various effects on dynamic responses of multiple rigid strip foundations.