Seismic ground reaction forces of rectangular underground structures: Insights from shear container model experiments using an aluminum-rod model ground
Seismic ground reaction forces of rectangular underground structures: Insights from shear container model experiments using an aluminum-rod model ground
Underground structures with rectangular cross-sections are subjected to racking deformation during earthquakes owing to the shear strain of the surrounding soil. Evaluating soilstructure interactions is therefore essential in seismic design. These interactions are strongly influenced by the shear stiffness ratio, which is defined as the ratio of the shear modulus of the structure to that of the soil. However, only a few experimental models have directly measured these interactions. In this study, shear container experiments were conducted to investigate the ground reaction forces acting on rectangular underground structures during earthquakes. The model ground comprised stacked aluminum rods that enabled two-dimensional experiments to reproduce the nonlinear behavior of medium-dense granular sand. It was constructed inside a shear container measuring 1500 mm in width and 800 mm in height, where seismic ground displacements were simulated by imposing shear deformation on the container sidewalls. A rectangular box model with a height and width of 200 mm was embedded at the center of the container to simulate the underground structure. The box model was designed to enable stiffness adjustments, and experiments were conducted over a broad range of shear stiffness ratios. Load cells were installed on all the surfaces of the box model to measure ground reactions. The shear and normal forces acting on the box exhibited minimal dependence on the box stiffness, whereas the eccentric moments, derived from the differences between the normal forces at two positions on each surface, were strongly affected by the box stiffness.
K. Takahashi; Hidetoshi Nishioka; Takafumi Shimada; T. Doi; J. Izawa
11th International Conference on Physical Modelling in Geotechnics (ICPMG2026)
Session 1: New facilities, new equipment, and measuring techniques
https://doi.org/10.53243/ICPMG2026-365