抄録
Large-scale liquefaction was caused by the 2011 off the Pacific coast of Tohoku, Japan, earthquake and many pipes in the liquefied ground suffered serious damages. One of the issues pointed out after the earthquake is the dynamic behavior and the mechanism of pipes near a structure in the liquefied ground. This study focuses on evaluating the dynamic behavior through centrifuge model test. Test results show that the uplift of pipes in the liquefied ground occurred during an earthquake and liquefaction happens at that time. After an earthquake, pipes start to sink with increasing effective stress. The characteristic of damage mechanism depends on the depth of pipes and the state of ground (in liquefiable layer, at ground water level, or in the unsaturated layer). The data also shows that the direction of force interacting pipes during liquefaction was only bending direction. So we should reconsider the design criteria for pipes which is widely used in Japan applying to axial force.
