Mitigation strategies and measures for frost heave hazards of chilled gas pipeline in permafrost regions: A review

With increasing gas resource development in the arctic regions, gas pipeline installations in permafrost regions are becoming important. Frost heave of pipeline foundation soils may occur when a chilled pipeline passes through unfrozen areas with frost-susceptible soils. Frost heave mitigations must be considered in the design and operation stage. Field monitoring and thaw settlement mitigative measures on a crude oil pipeline in permafrost regions have been widely documented. Numerous measures such as thermosyphons, thermal insulation layer, wood chips, and air-ventilated pipes have been developed and adopted in the Trans-Alaska (Alyeska) Pipeline System (TAPS), the Norman Wells pipeline (NWOP), and the China-Russia Crude Oil Pipelines (CRCOPs). However, gas pipelines in permafrost regions differ from oil pipelines in the construction configuration, transporting medium, and operation gas flow temperature control, facing new problems and challenges. There are only very limited direct experiences in designing and operating pipelines subjected to long-term frost heave under challenging arctic conditions. This article systematically reviews the formation mechanisms and mitigation strategies for differential frost heave along buried chilled gas pipelines in permafrost regions. Some of the special aspects of chilled gas pipelines in cold regions are highlighted and numerous frost heave mitigative measures are summarized. One pipe burial configuration with frost heave mitigation and monitoring measures is proposed for engineering application for the first time. It is hoped that new and innovative approaches can be inspired and envisioned for gas pipeline construction in the (sub)arctic, (sub)alpine, and high-plateau permafrost regions.