Abstract: Underground pipelines used to transport fresh water, natural gas and petroleum are especially vulnerable to earthquake due to its long and deep features. Moreover, they have enormously adverse effects on emergency rescue, energy transportation and restructure after the earthquake. Non-uniform wave propagation triggered by the earthquake is considered as one of the most important causes which destroy long deep underground pipelines. Recently, the problem has drawn extensive concerns. However, there are few studies of shaking table tests on a pipeline under non-uniform earthquake excitation due to the limited experimental equipment. For a long deep underground pipeline, the large-scale double independent controlled table was utilized to study the response of underground pipelines under three-directional non-uniform earthquake excitation. Then the responses of acceleration, strain and displacement of pipelines were discussed under different types of earthquake excitation. From experimental results, different impacts of deep underground pipelines were obviously found on the motions of the ground surface and soil surrounding with the pipeline. In addition, the differences of bending strains of pipeline were great under non-uniform excitation and uniform excitation. If the bending strains of pipelines under earthquake excitation are designed to weaken or even ignore, it is difficult to explain the bending buckling failure of underground pipelines.

Key words: non-uniform excitations, shaking table test, underground pipelines