Seismic response of buried reservoir structures: a comparison of numerical simulations with centrifuge experiments

Centrifuge experiments on seismic performance of relatively stiff underground reservoir structures in dry sand are modeled numerically. The capabilities of numerical simulations with calibrated equivalent linear soil properties in capturing the main features of experimentally measured responses are explored for both low and high amplitude earthquake motions. The scattering effects of the centrifuge container boundaries are also investigated by modeling the same soil deposit resting on an elastic bedrock and extending infinitely laterally, using the domain reduction method. It is observed that the calibrated equivalent linear soil models perform well in predicting accelerations, racking, and bending strains on the buried structure, even for high amplitude motions for which significant soil nonlinearity is expected. While not as accurate, the seismic lateral earth pressures predicted with these models are in fair agreement with direct measurements made with tactile sensors. The mismatches in earth pressures are likely due to local nonlinearities of soil and frictional contact, which were absent from the numerical models. It is also observed that the scattering effects of the container boundaries become more significant closer to the soil surface, and their characteristics are seen to depend on both the side boundaries and the embedded structure's stiffness.