Blast-induced dynamic response on the interface of a multilayered pipeline

This study presents an analytical vibration propagation model on a multilayered pipeline based on a full-scale field test and numerical studies. The derived analytical expressions are evaluated through comparison against 3D dynamic numerical analyses and field measurements in three-layered pipelines. In this study, the blasting test results from two sites are used for equation verification. When a wave propagates in a multilayered medium, its physical characteristics, such as velocity or pressure, change depending on the properties of the medium. Therefore, when an external wave passes through each stratum of a multilayered pipeline, the magnitude of pressure or velocity shows lower level than before. To obtain the wave pressure reduction model, the interface pressure should be defined in advance so that the stress distribution at the contact surface, derived from the Lame's equation of a thick-walled cylinder, can be estimated. Using the results of experimental and analytical approaches, the obtained maximum vibration velocity of steel (inner) pipe and high density polyethylene (outer) pipe is almost the same. The distributed and reduced pressure exhibits a lower pressure state and time-delayed wave propagation when passing through thick and loose filler.