Discrepancies of permafrost variations under thermal impacts from highway and railway on the Qinghai-Tibet Plateau

Jiang, Guanli; Zhao, Hongting; Liu, Yongzhi; Wu, Qingbai; Gao, Siru

doi:10.1016/j.coldregions.2023.103784

Cited by 8 publications

(2 citation statements)

References 51 publications

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“…The highway was built in December, 1954, and extensive paving and reconstruction were mainly carried out section by section through the 1980s-2000s to develop the existing asphalt pavement [31] The topography of the highway is high in the west and low in the east due to uplift in the QTP (Figure 1). Large-scale construction, particularly black asphalt pavement, has inevitably boosted heat absorption and altered heat and moisture transfer between paving layers and the frozen soil structure, further inducing ecological and environmental problems [32,33]. Vegetation is frequently used as an ecological indicator.…”

Section: Study Areamentioning

confidence: 99%

The Compound Effects of Highway Reconstruction and Climate Change on Vegetation Activity over the Qinghai Tibet Plateau: The G318 Highway as a Case Study

Guo,

Li,

Luo

et al. 2023

Remote Sensing

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The Qinghai–Tibet Plateau (QTP) is among one of the most sensitive regions to global environmental change worldwide. Although climate change and engineering construction on the QTP have jointly modified the regional vegetation activity, little is known about how this affects the vegetation variation. Using Moderate Resolution Imaging Spectroradiometer (MODIS) Enhanced Vegetation Index (EVI) data from 2000–2021, this study investigated the spatiotemporal variation of vegetation activity and the compound effects of climate change and reconstruction along the Tibetan section of the G318 national highway (TG318) through a novel contribution quantification model and partial correlation analysis, as well as through a structural equation model (SEM). The results showed that the mean growing-season EVI increased significantly at a rate of about 0.0020/year in the western side of the TG318 after reconstruction but fluctuated in the east. Reconstruction generally had a significant effect on the mean growing-season EVI, with contributions of 7.67%, 19.12%, 18.24%, and −4.15% in different sections of the TG318, whereas climate change contributed from −10.14% to 8.84% of the total variation. The mean growing-season EVI negatively correlated with snow cover and minimum temperature in humid and sub-humid regions, whereas it was positively related with vapor pressure in semi-arid regions. Moreover, there existed an obvious lag effect of climate change on the mean growing-season EVI, with lag time generally decreasing from west to east and apparent heterogeneity among different months and regions. These findings will help better understand the environmental impacts along the engineering corridors and provide a scientific basis for ecological conservation in the QTP regions.

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Section: Study Areamentioning

confidence: 99%

The Compound Effects of Highway Reconstruction and Climate Change on Vegetation Activity over the Qinghai Tibet Plateau: The G318 Highway as a Case Study

Guo,

Li,

Luo

et al. 2023

Remote Sensing

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“…The permafrost on the plateau is in the degenerating process with the thickness of active layer and ground temperature increasing, and even local permafrost disappearance in the last decades [4][5][6][7][8]. Under the influence of both climate warming and engineering construction, the permafrost under the Qinghai-Tibet railway, Qinghai-Tibet highway was accelerated to degenerate and warm, and that caused engineering problems in return, such as embankment settlement, crack, differential deformation, which could affect the engineering service performance directly [9][10][11][12][13]. To protect the underlying permafrost, a series of active cooling subgrade structure have been proposed to adjust thermal state through heat conduction, convection and radiation by using single or comprehensive application of insulation board, block gravel layer, ventilation pipe, thermosyphon, sunshade，and these methods have been demonstrated improving the thermal stability of highway and railway embankments [14][15][16][17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Heat transfer characteristics resembling thermal semiconductor of expressway embankment with ventilation and open-block layer in warm and high-altitude permafrost regions

Yuan,

Yu,

et al. 2024

Preprint

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Active cooling measures has been widely used to protect the underlying permafrost and maintain the embankment stability. Based on the measured data of high-grade highway experimental demonstration engineering in the Beiluhe area on the Qinghai-Tibet Plateau, the heat transfer process and ground temperature response have been analyzed to reveal the thermal control mechanism of the expressway embankment with ventilation and open block layer. (1) Heat was transferred through the block layer in both horizontal and vertical directions by different driving modes. In the horizontal direction, heat was transferred by forced convection under the driving of the local prevailing wind. In the vertical direction, heat was transferred upward by natural convection in the cold season and downward by heat conduction in the warm season under the driving of temperature gradient between the upper and lower boundaries of the block layer. (2) The expressway embankment structure showed the thermal semiconductor effect in both directions. The horizontal and vertical equivalent heat conductivity in the cold period was approximately 6.25 times and 3.5 times of that in the warm period. (3) The underlying frozen soil foundation was provided a net heat released state, and the total released heat was approximately 1.2 times of the total heat absorption. As the result, thick and wide cold permafrost layer (T<-1.0℃) was generated gradually, permafrost table increased and ground temperature decreased generally. This expressway embankment with ventilation duct and block layer contributed to protect the underlying permafrost layer and improve the stability of the frozen soil foundation in the warm and high-altitude permafrost regions.

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Pot‐Cover Effect in Permafrost Embankment: In Situ Experiment Evidence and Mechanism Simulation

Mingli,

Yuefeng,

Fei

et al. 2024

Num Anal Meth Geomechanics

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Under the influence of large temperature differences in an impermeable pavement layer of wide embankment in permafrost regions, liquid water accumulates at the bottom of the impermeable cover. The phenomenon is known as the pot‐cover effect and leads to an increase in soil water content and a reduction in bearing capacity of wide embankments. At present, water vapor and liquid water migrations and their effect on embankment thermal‐moisture stability have not been fully confirmed. To better understand the moisture transport and accumulation process within embankments, hydrothermal field monitoring was conducted from 2009 to 2011 on an asphalt concrete layer highway in Beiluhe, central Tibet Plateau. The field monitoring results show that soil moisture content between 50 and 250 cm below the pavement continuously increases with the number of freeze‐thaw cycles, with the largest increase during the 2 years being 6.4%. Then, a coupled hydro‐vapor‐thermal transport model was established and verified. Furthermore, the model was used to analyze the numerical recurrence of the pot‐cover effect. The simulation indicates that the upward migration of liquid water during the freezing period is less than the downward migration during the thawing period, while vapor migrates downward during the thawing period but upward during the freezing period. The migration of water vapor within the embankment during the freezing period is the main cause of the pot‐cover effect in permafrost regions. In addition, the research results can provide new ideas for understanding the internal mechanism of thermal‐moisture dynamics of the embankment and the stability prediction of permafrost engineering.

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Discrepancies of permafrost variations under thermal impacts from highway and railway on the Qinghai-Tibet Plateau

Cited by 8 publications

References 51 publications

The Compound Effects of Highway Reconstruction and Climate Change on Vegetation Activity over the Qinghai Tibet Plateau: The G318 Highway as a Case Study

The Compound Effects of Highway Reconstruction and Climate Change on Vegetation Activity over the Qinghai Tibet Plateau: The G318 Highway as a Case Study

Heat transfer characteristics resembling thermal semiconductor of expressway embankment with ventilation and open-block layer in warm and high-altitude permafrost regions

Pot‐Cover Effect in Permafrost Embankment: In Situ Experiment Evidence and Mechanism Simulation

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