Analysis on the settlement of roadway embankments in permafrost regions

Abstract

In permafrost regions, the embankment settlement results from several physical and mechanical processes taking place in the different soil layer, making its mechanism very complicated. Under the thermal influence of embankment, climate warming as well as geothermal source, permafrost may degrade downwards or upwards, which continuously changes the thicknesses of the permafrost layer and the also unfrozen soil layers. Thus, any attempt to analyze the embankment settlement seems to be very troublesome and difficult. In this paper, based on ground temperatures of embankment sections in five typical regions along the Qinghai-Tibet Highway (QTH), the trends of variation of different soil layers and the thermal gradients are investigated. On this basis, four types of sections, which can represent most of the sections of QTH, are deduced to clarify the possible settlement sources in different soil layers. In order to further confirm and investigate of the settlement sources, an embankment model test was carried out. Combing the in-situ monitoring data with the results from the model test, the main settlement sources in embankment settlement are discussed for the four types of sections respectively. The results will facilitate the analysis of embankment settlement in permafrost regions.

Keywords

Qinghai-Tibet Highway / permafrost / settlement sources / embankment model

References

[1] Jin H J, Zhao L, Wang S L, . Thermal Regimes and Degradation Modes of Permafrost along the Qinghai-Tibet Highway. Science in China Series D: Earth Sciences, 2006, 49(11): 1170-1183.

[2] Liu Y Z, Wu Q B, Zhang J M, . Deformation of Highway Roadbed in Permafrost Regions of the Tibetan Plateau. Journal of Glaciology and Geocryology, 2002, 24(1): 10-15.

[3] Ma W, Qi J L, Wu Q B. Analysis of the Deformation of Embankments on the Qinghai-Tibet Railway. Journal of Geotechnical and Geoenvironmental Engineering, 2008, 134: 1645-1654.

[4] Osterkamp T E, Romanovsky V E. Evidence of Warming and Thawing of Discontinuous Permafrost in Alaska. Permafrost and Periglacial Processes, 1999, 10: 17-37.

[5] Qi J L, Sheng Y, Zhang J M, . Settlement of Embankment in Permafrost Regions in the Qinghai-Tibet Plateau. Norwegian Journal of Geography, 2007, 61(2): 49-55.

[6] Qi J L, Yao X L, Yu F, . Study on Thaw Consolidation of Permafrost under Roadway Embankment. Cold Regions Science and Technology, 2012, 81: 48-54.

[7] Wang S L, Mi H Z. The Change of Permafrost under Roadbed with Asphalt Pavement along the Qinghai-Tibet Highway. Journal of Glaciology and Geocryology, 1993, 15(4): 566-573.

[8] Wen Z, Sheng Y, Ma W, . Ground Temperature and Deformation Laws of Highway Embankments in Degenerative Permafrost Regions. Chinese Journal of Rock Mechanics and Engineering, 2009, 28(7): 1477-1483.

[9] Williams P J, Burt T P. Measurement of Hydraulic Conductivity of Frozen Soils. Canada Geotechnical Journal, 1974, 11(4): 647-650.

[10] Wu Q B, Dong X F, Liu Y Z, . Responses of Permafrost on the Qinghai-Tibet Plateau, China, to Climate Change and Engineering Construction. Arctic, Antarctic, and Alpine Research, 2007, 39(4): 682-687.

[11] Wu Q B, Liu Y Z. Ground Temperature Monitoring and its Recent Change in Qinghai-Tibet Plateau. Cold Regions Science and Technology, 2004, 38(2–3): 85-92.

[12] Wu Q B, Liu Y Z, Zhang J M, . A Review of Recent Frozen Soil Engineering in Permafrost Regions along Qinghai-Tibet Highway, China. Permafrost and Periglacial Processes, 2002, 13(3): 199-205.

[13] Wu Q B, Zhang J M, Liu Y Z. Long-Term Thermal Effect of Asphalt Pavement on Permafrost under an Embankment. Cold Regions Science and Technology, 2010, 60(3): 221-229.

[14] Journal of Geophysical Research: Atmospheres, 2008, 113 D13

[15] Wu Z W, Cheng G D, Zhu L N, . Roadbed Engineering in Permafrost Region, 1988 Lanzhou: Lanzhou University Press

[16] Wu Z W, Liu Y Z. Frozen Subsoil and Engineering, 2005 Beijing: Ocean Press, 72-84.

[17] Xu X Z, Wang J C, Deng Y S. Thermo-Physic of Frozen Soil, 2010 Beijing: Science Press, 112-116.

[18] Yu F, Qi J L, Yao X L. Monitoring Settlement at Different Depths within an Embankment in Permafrost Region. Journal of Glaciology and Geocryology, 2011, 33(4): 813-818.

[19] Yu F, Qi J L, Yao X L, . Degradation Process of Permafrost underneath Embankments along Qinghai-Tibet Highway: An Engineering View. Cold Regions Science and Technology, 2013, 85: 150-156.

[20] Zhang J M, Li D, Qi J L. Estimation on the Settlement and Deformation of Embankment along Qinghai-Tibet Railway in Permafrost Regions. China Railway Science, 2007, 28(3): 12-17.

[21] Zhao S P, Ma W, Jiao G D, . Design of Model Test System for Cold Regions Engineering with Dynamic Loading. Journal of Glaciology and Geocryology, 2011, 33(4): 826-832.