降雨增加对多年冻土区铁路路基水热影响研究
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摘要
近50 a青藏高原湿化趋势显著,降雨变化导致地表能量平衡过程、活动层水分状况和水热输运过程改变。以青藏高原北麓河铁路路基试验段水分监测为基础,基于土壤–地表–大气能量平衡的冻土水–汽–热耦合模型研究在未来降雨变化情景下,降雨对冻土路基水热的影响机制与过程。结果表明:近6 a路基水分监测显示,虽然青藏高原年降雨量变化较大,夏季降雨引起土体表层水分短期显著波动,但长期路基含水量并未明显累积,路基蒸发、液态水与水汽运移显著;在未来湿化背景下,年降雨量增大导致地表潜热增大地表土壤热通量减小,降雨增大导致的热传导通量减小量比液态水对流热通量增大更大,人为冻土上限抬升;降雨增加缓解了路基工程对下伏多年冻土的热扰动,但降雨增加导致活动层水分累积,增大路基冻胀和融沉灾害风险。
Changes of air temperature or rainfall will inevitably influence the embankment stability in permafrost regions. Previous studies focused mainly on the influence of air temperature on the thermal stability of the embankment,while the influences of rainfall on the embankment and the influencing mechanism have not been fully considerated. Moreover,the understanding on the role of rainfall is still controversial. Observed data showed that the rainfall increased significantly on the Qinghai—Tibet Plateau during the past 50 years. The increase in rainfall can result in the change of the thermal-moisture activity in the active layer,the near-surface energy and the mass budget. The in-site precipitation and moisture data within railway embankment been measured in Beiluhe permafrost station and the water-vapor-heat transport model established were used to predict the process and mechanism of influence of increasing rainfall on gravel embankment. Collected data indicated that rainfall in summer significantly affected the shallow moisture in short time. But the long-term water content was not affected by rainfall, the moisture evaporation and the liquid water and water vapor transfer in embankment occurred clearly. The increase in rainfall will increase the surface latent heat,lower the heat flux and temperature of surface soil,and raise the artificial permafrost table. The reduction of heat conduction caused by increased rainfall is greater than the increase of heat convection of liquid water. Therefore,the increase in rainfall can mitigate the process of permafrost degradation and will alleviate the thermal influence of embankment engineering on underlying permafrost. While,the increased rainfall infiltrations will result in the increase of water content in embankment and induce the frost heave and thawing settlement.
Changes of air temperature or rainfall will inevitably influence the embankment stability in permafrost regions. Previous studies focused mainly on the influence of air temperature on the thermal stability of the embankment,while the influences of rainfall on the embankment and the influencing mechanism have not been fully considerated. Moreover,the understanding on the role of rainfall is still controversial. Observed data showed that the rainfall increased significantly on the Qinghai—Tibet Plateau during the past 50 years. The increase in rainfall can result in the change of the thermal-moisture activity in the active layer,the near-surface energy and the mass budget. The in-site precipitation and moisture data within railway embankment been measured in Beiluhe permafrost station and the water-vapor-heat transport model established were used to predict the process and mechanism of influence of increasing rainfall on gravel embankment. Collected data indicated that rainfall in summer significantly affected the shallow moisture in short time. But the long-term water content was not affected by rainfall, the moisture evaporation and the liquid water and water vapor transfer in embankment occurred clearly. The increase in rainfall will increase the surface latent heat,lower the heat flux and temperature of surface soil,and raise the artificial permafrost table. The reduction of heat conduction caused by increased rainfall is greater than the increase of heat convection of liquid water. Therefore,the increase in rainfall can mitigate the process of permafrost degradation and will alleviate the thermal influence of embankment engineering on underlying permafrost. While,the increased rainfall infiltrations will result in the increase of water content in embankment and induce the frost heave and thawing settlement.
引文
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[9]SUBIN Z M,KOVEN C D,RILEY W J,et al.Effects of soil moisture on the responses of soil temperatures to climate change in cold regions[J].Journal of Climate,2013,26(10):3 139–3 158.
[10]ZHANG S Y,LI X Y,MA Y J,et al.Interannual and seasonal variability in evapotranspiration and energy partitioning over the alpine riparian shrub Myricaria squamosa Desv.on Qinghai—Tibet Plateau[J].Cold Regions Science and Technology,2014,102(6):8–20.
[11]KOKELJ S V,TUNNICLIFFE J,LACELLE D,et al.Increased precipitation drives mega slump development and destabilization of ice-rich permafrost terrain,northwestern Canada[J].Global and Planetary Change,2015,129:56–68.
[12]WU Q B,HOU Y D,YUN H B,et al.Changes in active-layer thickness and near-surface permafrost between 2002 and 2012 in alpine ecosystems,Qinghai—Tibet Plateau,China[J].Global and Planetary Change,2015,124:149–155.
[13]KOKFELT U,ROSéN P,SCHONING K,et al.Ecosystem responses to increased precipitation and permafrost decay in subarctic Sweden inferred from peat and lake sediments[J].Global Change Biology,2009,15(7):1 652–1 663.
[14]ROMANOVSKY V E,DROZDOV D S,OBERMAN N G,et al.Thermal state of permafrost in Russia[J].Permafrost and Periglacial Processes,2010,21(2):136–155.
[15]HARLAN R L.Ananalys of coupled heat-fluid transport in partially frozen soil[J].Water Resources Research,1973,(9):1 314–1 323.
[16]O?NEIL K,MILLER R D.Exploration of a rigid ice model of frost heave[J].Water Resources Research,1985,21(3):281–296.
[17]LAI Y M,PEI W S,LI S Y,et al.Study on theory model of hydro-thermal-mechanical interaction process in saturated freezing silty soil[J].International Journal of Heat and Mass Transfer,2014,78(5):805–819.
[18]MCKENZIE J M,VOSS C I,SIEGEL D I.Groundwater flow with energy transport and water–ice phase change:numerical simulations,benchmarks,and application to freezing in peat bogs[J].Advances in Water Resources,2007,30(4):966–983.
[19]BENSE V F,KOOI H,FERGUSON G,et al.Permafrost degradation as a control on hydrogeological regime shifts in a warming climate[J].Journal of Geophysical Research Atmospheres,2012,117(F3):03036.DOI:10.1029/2011JF002143.
[20]GE S,MCKENZIE J,VOSS C,et al.Exchange of groundwater and surface-water mediated by permafrost response to seasonal and long term air temperature variation[J].Geophysical Research Letters,2011,38(14):L14402.DOI:10.1029/2011GL047911.
[21]ZHANG S,TENG J,HE Z,et al.Canopy effect caused by vapour transfer in covered freezing soils[J].Géotechnique,2016,66(11):927–940.
[22]ZHANG S,TENG J,HE Z,et al.Importance of vapor flow in unsaturated freezing soil:a numerical study[J].Cold Regions Science and Technology,2016,126(6):1–9.
[23]SAKAI M,TORIDE N,?IMU NEK J.Water and vapor movement with condensation and evaporation in a sandy column[J].Soil Science Society of America Journal,2009,73(3):707–717.
[24]SAITO H,SIMUNEK J,MOHANTY B P.Numerical analysis of coupled water,vapor,and heat transport in the vadose zone[J].Vadose Zone Journal,2006,5(2):784–800.
[25]ZENG Y J,SU Z B,WAN L,et al.A simulation analysis of the advective effect on evaporation using a two-phase heat and mass flow model[J].Water Resource Research,2011,47(10),W10529.DOI:10.1029/2011WR010701.
[26]ZENG Y J.Coupled Dynamics in soil:experimental and numerical studies of energy,momentum and mass transfer[M].New York:Springer Heidelberg,2012:1–65.
[27]ROWLAND J C,TRAVIS B J,WILSON C J.The role of advective heat transport in talik development beneath lakes and ponds in discontinuous permafrost[J].Geophysical Research Letters,2011,38(17):L24803.DOI:10.1029/2011GL048497
[28]FRAMPTON A,PAINTER S,LYON SW,et al.Non-isothermal,three-phase simulations of near-surface flows in a model permafrost system under seasonal variability and climate change[J].Journal of Hydrology,2011,403(3):352–359.
[29]KARRA S,PAINTER S,LICHTNER P.Three-phase numerical model for subsurface hydrology in permafrost-affected regions(PFLOTRANICE v1.0)[J].The Cryosphere,2014,8(5):1 935–1 950.
[30]吴紫汪,程国栋,朱林楠,等.冻土路基工程[M].兰州:兰州大学出版社,1988:48–60.(WU Ziwang,CHENG Guodong,ZHU Linnan,et al.Permafrost subgrade engineering[M].Lanzhou:Lanzhou University,1988:48–60.(in Chinese))
[31]DALL’AMICO M,ENDRIZZI S,GRUBER S,et al.A robust and energy-conserving model of freezing variably-saturated soil[J].The Cryosphere,2011,5(2):469–484.
[32]ENDRIZZI S,GRUBER S,DALL'AMICO M,et al.GEOtop 2.0:simulating the combined energy and water balance at and below the land surface accounting for soil freezing,snow cover and terrain effects[J].Geoscientific Model Development Discussions,2014,7(6):2 831–2 857.
[33]张明礼,温智,薛珂,等.降水对北麓河地区多年冻土活动层水热影响分析[J].干旱区资源与环境,2016,30(4):159–164.(ZHANG Mingli,WEN Zhi,XUE Ke,et al.The effects of precipitation on thermal-moisture dynamics of active layer at Beiluhe permafrost region[J].Journal of Arid Land Resources and Environment,2016,30(4):159–164.(in Chinese))
[34]谭贤君,陈卫忠,伍国军,等.低温冻融条件下岩体温度–渗流–应力–损伤(THMD)耦合模型研究及其在寒区隧道中的应用[J].岩石力学与工程学报,2013,32(2):239–250.(TAN Xianjun,CHEN Weizhong,WU Guojun,et al.Study of thermo-hydromechnical-damage(THMD)coupled model in the condition of freeze-thaw cycles and its application to cold region tunnels[J].Chinese Journal of Rock Mechanics and Engineering,2013,32(2):239–250.(in Chinese))
[35]ZHANG M L,WEN Z,XUE K,et al.A coupled model for liquid water,water vapor and heat transport of saturated–unsaturated soil in cold regions:model formulation and verification[J].Environmental Earth Sciences,2016,75(8):1–19.
[36]林家鼎,孙菽芬.土壤内水分流动、温度分布及其表面蒸发效应的研究——土壤表面蒸发阻抗的探讨[J].水利学报,1983,(7):1–8.(LIN Jiading,SUN Shufen.A study of moisture and heat transport in siol and the effect of surface resistance to evaporation[J].Journal of Hydraulic Engineering,1983,(7):1–8.(in Chinese))
[37]BANIMAHD S A,ZAND-PARSA S.Simulation of evaporation,coupled liquid water,water vapor and heat transport through the soil medium[J].Agricultural Water Management,2013,130:168–177.
[38]LINSLEY R K,KOHLER M A,PAULHUS J L H.Hydrology for Engineers[M].London:Mc Graw-Hill International Book Company,1982:62–87.
[39]CAMILLO P J,GURNEY R J.A resistance parameter for bare-soil evaporation models[J].Soil Science,1986,141(2):95–105.
[40]ADRIAAN A,VAN D G,OWE M.Bare soil surface resistance to evaporation by vapor diffusion under semiarid conditions[J].Water Resources Research,1994,30(2):181–188.
[41]徐敩祖,王家澄,张立新.冻土物理学[M].北京:科学出版社,2010:61–97.(XU Xiaozu,WANG Jiacheng,ZHANG Lixin.Frozen soil physics[M].Beijing:Science Press,2010:61–97.(in Chinese))
[2]LI S Y,LAI Y M,PEI W S,et al.Moisture-temperature changes and freeze-thaw hazards on a canal in seasonally frozen regions[J].Natural Hazards,2014,72(2):287–308.
[3]张明礼,温智,薛珂,等.青藏铁路多年冻土区润湿地段斜坡路基温度与变形分析[J].岩石力学与工程学报,2016,35(8):1 677–1 687.(ZHANG Mingli,WEN Zhi,XUE Ke,et al.Temperature and deformation analysis on slope subgrade with rich moisture of Qinghai—Tibet railway in permafrost regions[J].Chinese Journal of Rock Mechanics and Engineering,2016,35(8):1 677–1 687.(in Chinese))
[4]WEN Z,ZHANG M L,MA W,et al.Thermal-moisture dynamics of embankments with asphalt pavement in permafrost regions of central Tibetan Plateau[J].European Journal of Environmental and Civil Engineering,2015,19(4):387–399.
[5]MA W,CHENG G,WU Q.Construction on permafrost foundations:Lessons learned from the Qinghai—Tibet railroad[J].Cold Regions Science and Technology,2009,59(1):3–11.
[6]SU F,DUAN X,CHEN D,et al.Evaluation of the global climate models in the CMIP5 over the Tibetan Plateau[J].Journal of Climate,2013,26(10):3 187–3 208.
[7]胡芩,姜大膀,范广洲.青藏高原未来气候变化预估:CMIP5模式结果[J].大气科学,2015,39(2):260–270.(HU Qin,JIANG Dabang,FAN Guangzhou.Climate change projection on the Tibetan Plateau:Results of CMIP5 models[J].Chinese Journal of Atmospheric Sciences,2015,39(2):260–270.(in Chinese))
[8]ZHANG T,BARRY R G,GILICHINSKY D,et al.An amplified signal of climatic change in soil temperatures during the last century at Irkutsk,Russia[J].Climatic Change,2001,49(1/2):41–76.
[9]SUBIN Z M,KOVEN C D,RILEY W J,et al.Effects of soil moisture on the responses of soil temperatures to climate change in cold regions[J].Journal of Climate,2013,26(10):3 139–3 158.
[10]ZHANG S Y,LI X Y,MA Y J,et al.Interannual and seasonal variability in evapotranspiration and energy partitioning over the alpine riparian shrub Myricaria squamosa Desv.on Qinghai—Tibet Plateau[J].Cold Regions Science and Technology,2014,102(6):8–20.
[11]KOKELJ S V,TUNNICLIFFE J,LACELLE D,et al.Increased precipitation drives mega slump development and destabilization of ice-rich permafrost terrain,northwestern Canada[J].Global and Planetary Change,2015,129:56–68.
[12]WU Q B,HOU Y D,YUN H B,et al.Changes in active-layer thickness and near-surface permafrost between 2002 and 2012 in alpine ecosystems,Qinghai—Tibet Plateau,China[J].Global and Planetary Change,2015,124:149–155.
[13]KOKFELT U,ROSéN P,SCHONING K,et al.Ecosystem responses to increased precipitation and permafrost decay in subarctic Sweden inferred from peat and lake sediments[J].Global Change Biology,2009,15(7):1 652–1 663.
[14]ROMANOVSKY V E,DROZDOV D S,OBERMAN N G,et al.Thermal state of permafrost in Russia[J].Permafrost and Periglacial Processes,2010,21(2):136–155.
[15]HARLAN R L.Ananalys of coupled heat-fluid transport in partially frozen soil[J].Water Resources Research,1973,(9):1 314–1 323.
[16]O?NEIL K,MILLER R D.Exploration of a rigid ice model of frost heave[J].Water Resources Research,1985,21(3):281–296.
[17]LAI Y M,PEI W S,LI S Y,et al.Study on theory model of hydro-thermal-mechanical interaction process in saturated freezing silty soil[J].International Journal of Heat and Mass Transfer,2014,78(5):805–819.
[18]MCKENZIE J M,VOSS C I,SIEGEL D I.Groundwater flow with energy transport and water–ice phase change:numerical simulations,benchmarks,and application to freezing in peat bogs[J].Advances in Water Resources,2007,30(4):966–983.
[19]BENSE V F,KOOI H,FERGUSON G,et al.Permafrost degradation as a control on hydrogeological regime shifts in a warming climate[J].Journal of Geophysical Research Atmospheres,2012,117(F3):03036.DOI:10.1029/2011JF002143.
[20]GE S,MCKENZIE J,VOSS C,et al.Exchange of groundwater and surface-water mediated by permafrost response to seasonal and long term air temperature variation[J].Geophysical Research Letters,2011,38(14):L14402.DOI:10.1029/2011GL047911.
[21]ZHANG S,TENG J,HE Z,et al.Canopy effect caused by vapour transfer in covered freezing soils[J].Géotechnique,2016,66(11):927–940.
[22]ZHANG S,TENG J,HE Z,et al.Importance of vapor flow in unsaturated freezing soil:a numerical study[J].Cold Regions Science and Technology,2016,126(6):1–9.
[23]SAKAI M,TORIDE N,?IMU NEK J.Water and vapor movement with condensation and evaporation in a sandy column[J].Soil Science Society of America Journal,2009,73(3):707–717.
[24]SAITO H,SIMUNEK J,MOHANTY B P.Numerical analysis of coupled water,vapor,and heat transport in the vadose zone[J].Vadose Zone Journal,2006,5(2):784–800.
[25]ZENG Y J,SU Z B,WAN L,et al.A simulation analysis of the advective effect on evaporation using a two-phase heat and mass flow model[J].Water Resource Research,2011,47(10),W10529.DOI:10.1029/2011WR010701.
[26]ZENG Y J.Coupled Dynamics in soil:experimental and numerical studies of energy,momentum and mass transfer[M].New York:Springer Heidelberg,2012:1–65.
[27]ROWLAND J C,TRAVIS B J,WILSON C J.The role of advective heat transport in talik development beneath lakes and ponds in discontinuous permafrost[J].Geophysical Research Letters,2011,38(17):L24803.DOI:10.1029/2011GL048497
[28]FRAMPTON A,PAINTER S,LYON SW,et al.Non-isothermal,three-phase simulations of near-surface flows in a model permafrost system under seasonal variability and climate change[J].Journal of Hydrology,2011,403(3):352–359.
[29]KARRA S,PAINTER S,LICHTNER P.Three-phase numerical model for subsurface hydrology in permafrost-affected regions(PFLOTRANICE v1.0)[J].The Cryosphere,2014,8(5):1 935–1 950.
[30]吴紫汪,程国栋,朱林楠,等.冻土路基工程[M].兰州:兰州大学出版社,1988:48–60.(WU Ziwang,CHENG Guodong,ZHU Linnan,et al.Permafrost subgrade engineering[M].Lanzhou:Lanzhou University,1988:48–60.(in Chinese))
[31]DALL’AMICO M,ENDRIZZI S,GRUBER S,et al.A robust and energy-conserving model of freezing variably-saturated soil[J].The Cryosphere,2011,5(2):469–484.
[32]ENDRIZZI S,GRUBER S,DALL'AMICO M,et al.GEOtop 2.0:simulating the combined energy and water balance at and below the land surface accounting for soil freezing,snow cover and terrain effects[J].Geoscientific Model Development Discussions,2014,7(6):2 831–2 857.
[33]张明礼,温智,薛珂,等.降水对北麓河地区多年冻土活动层水热影响分析[J].干旱区资源与环境,2016,30(4):159–164.(ZHANG Mingli,WEN Zhi,XUE Ke,et al.The effects of precipitation on thermal-moisture dynamics of active layer at Beiluhe permafrost region[J].Journal of Arid Land Resources and Environment,2016,30(4):159–164.(in Chinese))
[34]谭贤君,陈卫忠,伍国军,等.低温冻融条件下岩体温度–渗流–应力–损伤(THMD)耦合模型研究及其在寒区隧道中的应用[J].岩石力学与工程学报,2013,32(2):239–250.(TAN Xianjun,CHEN Weizhong,WU Guojun,et al.Study of thermo-hydromechnical-damage(THMD)coupled model in the condition of freeze-thaw cycles and its application to cold region tunnels[J].Chinese Journal of Rock Mechanics and Engineering,2013,32(2):239–250.(in Chinese))
[35]ZHANG M L,WEN Z,XUE K,et al.A coupled model for liquid water,water vapor and heat transport of saturated–unsaturated soil in cold regions:model formulation and verification[J].Environmental Earth Sciences,2016,75(8):1–19.
[36]林家鼎,孙菽芬.土壤内水分流动、温度分布及其表面蒸发效应的研究——土壤表面蒸发阻抗的探讨[J].水利学报,1983,(7):1–8.(LIN Jiading,SUN Shufen.A study of moisture and heat transport in siol and the effect of surface resistance to evaporation[J].Journal of Hydraulic Engineering,1983,(7):1–8.(in Chinese))
[37]BANIMAHD S A,ZAND-PARSA S.Simulation of evaporation,coupled liquid water,water vapor and heat transport through the soil medium[J].Agricultural Water Management,2013,130:168–177.
[38]LINSLEY R K,KOHLER M A,PAULHUS J L H.Hydrology for Engineers[M].London:Mc Graw-Hill International Book Company,1982:62–87.
[39]CAMILLO P J,GURNEY R J.A resistance parameter for bare-soil evaporation models[J].Soil Science,1986,141(2):95–105.
[40]ADRIAAN A,VAN D G,OWE M.Bare soil surface resistance to evaporation by vapor diffusion under semiarid conditions[J].Water Resources Research,1994,30(2):181–188.
[41]徐敩祖,王家澄,张立新.冻土物理学[M].北京:科学出版社,2010:61–97.(XU Xiaozu,WANG Jiacheng,ZHANG Lixin.Frozen soil physics[M].Beijing:Science Press,2010:61–97.(in Chinese))