Abstract: This paper presents a case history of design and construction of a gas pipeline in frozen soils. The paper first introduces the distribution and engineering properties of frozen soils. The potential hazard of pipelines over the frozen soils and their mitigation measures are then proposed. For engineered facilities in frozen soils, proper geotechnical investigations are necessary in order to characterize the frozen soils and their engineering properties. In general, pipelines should not be installed in soils with seasonal freezes and thaws. In the freeze expansion zone, the pipeline should be backfilled with nonfrost heave materials such as, coarse or medium sands, slags or crushed stones. The surface runoff water should be prevented to flow into the excavated trenches.

Key words: Frozen Soils, Frozen Soil Depths, Engineering Characteristics