Analysis on thawing consolidation and deformation of ground under earthen embankment in warm permafrost region

作者：Tian Yahu^*; Zhang Qinglong; Mu Yanhu; Liu Yongzhi

来源：China Railway Science, 2014, 35(3): 1-7.

DOI：10.3969/j.issn.1001-4632.2014.03.01

• Embankment construction
• Embankment settlement
• Geological conditions
• Large strain consolidation
• Qinghai Tibet railway
• Thermal conduction equation
• Traditional embankments
• Warm permafrost

Considering the thawing settlement of traditional embankments along Qinghai-Tibet Railway in warm permafrost regions, the large strain consolidation theory was proposed by combining large strain consolidation theory with UL (Updated Lagrangian) description and thermal conduction equation with phase change. The thermal regimes and thawing settlements of embankments with various heights in warm permafrost regions were researched according to the proposed theory and the calculations of temperature and settlement were compared with in-situ monitoring results. Thermal calculation results indicate that the permafrost table moves upwards slightly beneath the 4 m-height or 6 m-height embankments in the first few years after embankment construction, but the underlying permafrost warms slowly, and the increase gradient of ground temperature is about 0.02°C annually. Under climate warming, the permafrost table begins to decline quickly in late stage of embankment construction. The lower the embankment is, the larger the table's decline is, and finally thaw bulb occurs beneath embankment. The analysis results of thawing consolidation and deformation show that the embankment settlement develops quickly during the warm seasons but slowly in cold seasons, which changes in a seasonal trend and has good agreement with field monitoring results. The settlements of 2, 4 and 6 m-height embankments with the given geological conditions used in calculation are 255.2, 470.4 and 689.7 mm after 50 years of the construction respectively. The higher the embankment is, the larger the thawing settlement is, and the seasonal trend of settlement is more obvious. The height of embankment and ice content of frozen soil are the major influence factors of embankment settlement in permafrost regions.

• 出版日期2014
• 单位北京交通大学