埋地管道在冻土带的热力变形分析

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。文章分析了永冻土的特点,建立了永冻土地带土壤传热数学模型:融化圈内外传热方程、管道向土壤和土壤表面向大气所放热量的守恒关系、融化圈界面处土壤温度、相变界面处固相变为液相的传热条件。还建立了埋地管道模型,并以穿过永冻土地带土壤的输油管道为例,分析并计算了各种应力的最大值所在的位置和大小,提出了在永冻土地带减小管道热力变形的措施。

Analysis of Thermal Deformation of Buried Pipeline in Permafrost Zone

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. This article analyzes the characteristics of permafrost earth, establishes mathematical model of earth thermal transfer, which consists of thermal transfer equation in thaw zone, the conservation relationship of heat quantity transferring from pipeline to earth and from earth surface to atmosphere, earth temperatures at thaw zone interface, heat transfer condition of solid phase changing into liquid phase at phase interface. Taking an oil pipeline passing through permafrost as an example, the paper calculates and analyzes the positions and magnitudes of various maximum stresses, then put forwards the measures of reducing thermal deformation of pipeline in permafrost zone.