When a buried pipeline goes through permafrost zone, thermal action between medium in pipeline and permafrost occurs and causes the frozen earth thawing, so the thaw settlement forms around the pipeline.

• 摘要埋地油气管道通过永冻土地带时，由于管内介质与周围的冻土发生了热力作用，使冰土解冻，在管道周围形成融化圈。