29. Centrifuge Modeling of Dynamic Behavior of Box Shaped Underground Structures in Sand

Seismic safety of underground facilities such as pipelines, culverts, subways and tunnels becomes an essential requirement for sustained economic and social development. Many engineers earlier thought that the underground structures had been inherently safe against earthquakes, but then, especially after the failure of some underground facilities during 1995 Kobe, Japan, 1999 Kocaeli, Turkey and 1999 Chi Chi, Taiwan earthquakes the safety evaluation of underground structures has become a major concern of the engineers. This research aims to investigate the dynamic response of box shaped underground structures buried in dry sand. For this purpose, a series of centrifuge tests were carried out under harmonic sinusoidal motions by considering the nonlinear behavior of both structure and surrounding soil. Hence, response of model ground and deformation of the buried models were examined with special reference to the dynamic soil structure interaction. A specific variable considered in this study is the rigidity of buried box structures. Three different models with varying rigidities were used in the tests. Different deformations schemes of the sidewalls were analyzed under harmonic motions. Results of the centrifuge experiments were evaluated and compared to the predictions obtained from closed-form solutions recommended in the literature.