A model experiment was carried out on the seismic behavior of a buried pipeline in a partially liquefied ground. A model pipeline was laid in an unliquefiable superficial soil layer, and a part of soil layer underneath the superficial layer was made liquefiable by using loose fine sand. When liquefaction occurred, the superficial layer and the pipe showed a characteristic behavior which could be simulated with simple mathematical models with a high accuracy. Calculations of strains in buried

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... elines of the actual sizes by using the above mathematical models showed that extremely great strains could be produced in the pipelines during the actual earthquakes. Thus the models of partially liquefied ground will give a most probable mechanism of pipeline failure associated with soil liquefaction.