青藏高原多年冻土区埋地输气管道周围温度场数值分析

通过建立管道与多年冻土热相互作用的计算模型，利用数值分析方法探究了不同管温（输运温度）工况下冷输天然气管道对管周土体冻融过程和多年冻土热稳定性的影响。研究表明：5℃正温输运天然气管道可造成下覆冻土上限下降约11倍管径，管周多年冻土退化严重；0℃输运会导致管底下部高温不稳定冻土范围扩大，管底土体强度及承载性能降低，不利于保持多年冻土和管道运营稳定性；-1℃和-5℃负温输运可有效提高冻土人为上限，保持管底冻土温度稳定，但-5℃时管道下部土体温度降低明显，可能导致冻胀病害发生。就管周冻土热稳定性而言，在青藏高原多年冻土区采用冷输（负温输送）工艺输运天然气有利于保护管周多年冻土，是可行的。

Numerical analysis of temperature fields around the buried gas pipeline in permafrost regions of Qinghai-Tibet Plateau

In the paper, with different pipeline temperatures set, a thermal model of the interaction between pipeline and permafrost is established to investigate the influence of chilled pipelines on the freezing and thawing of soil around pipeline and thermal stability of permafrost. The results show that warm gas pipeline of 5℃ could decrease the value of permafrost table below pipeline about 11 times diameter and aggravate the degradation of permafrost around pipeline; gas pipeline of 0℃ will expand the range of high-temperature unstable permafrost below the pipeline, decreasing the strength and bearing capacity of frozen soil below the pipeline, which is not conducive to maintaining permafrost and pipeline operation stability; -1℃ and -5℃ chilled gas pipeline can effectively improve the permafrost table and maintain the temperature stability of frozen soil below pipeline, but the temperature of soils below pipeline of -5℃ decreases obviously, which may lead to frost heave of soil. In terms of thermal stability around pipeline, the chilled gas transmission technology can protect permafrost and can be applied to the gas pipeline construction in permafrost region of Qinghai-Tibet Plateau.