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laboratory test on the combined cooling effect of L-shaped thermosyphons and thermal insulation on high-grade roadway construction in permafrost regions

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research in cold and arid Regions 2009年第4期1卷 307-315页

作者： yuanhong dong,yuanming lai,mingyi zhang,{3.,cold and arid Regions environmental and engineering research institute,chinese academy of sciences,lanzhou,gansu 73.000,{13. state key laboratory of {3. soil engineering Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences cold and arid Regions environmental and {3. research institute Chinese Academy of Sciences

With the completion of the Qinghai-Tibetan Railway,economic development of related areas has been greatly ***,in return,calls for building or upgrading more roadways,especially high-grade *** cold regions,the thawing of permafrost can induce settlement damage of and even failure to railway (or roadway) *** (self-powered refrigera-tion devices that are used to help keep the permafrost cool) have proved effective in mitigating thaw settlement by maintaining the thermal stability of the ***,for high-grade roadway embankments of great width,stabilizing or cooling ef-fects of traditional geotechnological measures may be *** enhance the cooling effect of thermosyphons,an L-shaped thermosyphon was designed.A laboratory test was carried out to study the combined cooling effect of the L-shaped thermosyphon and thermal insulation applying to roadbed *** angle between the evaporator and condenser sections of the L-shaped thermosyphon is 13. degrees,and the L-shaped thermosyphon was inserted into the soil at an angle of 5 degrees with the road *** tested results show that the L-shaped thermosyphon is effective in removing heat from a roadway in *** the ambient air temperature is lower than the soil temperature,the thermosyphon is active and extracts the heat in the soil around *** the ambient air temperature is higher than the soil temperature,the thermosyphon is inactive,and no heat is in-jected into the soil through the L-shaped *** to embankments with straight thermosyphons,the inner parts of the embankments with L-shaped thermosyphons were significantly *** is hoped that the present study would be useful to the application of L-shaped thermosyphons in the construction of high-grade roadways in cold regions.

关键词： L-shaped thermosyphon thermal insulation cooling effect foundation soils high-grade roadway

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Experimental study on the movement of oil spill under freeze-thaw action

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research in cold and arid Regions 2024年第3期16卷 111-120页

作者： Zeliang Ye JianGuo Lu mingyi zhang WanSheng Pei ShuTong li state key laboratory of {3. soil engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhouGansu 730000China key laboratory of Cryospheric Science and frozen {3. engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhouGansu 730000China University of chinese academy of sciences Beijing 100049China School of Civil engineering and Geomatics Southwest Petroleum UniversityChengduSichuan 610500China

Oil leakages cause environmental pollution,economic losses,and even engineering safety *** cold regions,{3.ers urgently investigate the movement of oil spill in soils exposed to freeze-thaw *** this study,a series of laboratory model experiments were carried out on the migration of oil leakage under freeze-thaw action,and the distributions of the soil temperature,unfrozen water content,and displacement were *** results showed that under freeze-thaw action,liquid water in soils migrated to the freezing front and *** the pipe cracked,oil pollutants first gathered at one side of the leak hole,and then moved *** pipe wall temperature affected the soil temperature field,and the thermal influence range below and transverse the pipe wall(3.–40 cm)was larger than that above the pipe wall(8 cm)owing to the soil surface *** leaked oil's temperature would make the temperature of the surrounding soil *** would inhibit the cooling of the ***,oil migration was significantly affected by the gravity and water flow *** freeze-thaw action would affect the migration of the oil,which was mainly manifested as inhibiting the diffusion and movement of oil when soils were *** water transport caused by freeze-thaw cycles would also inhibit oil *** {3. results would provide a scientific reference for understanding the relationship between the movement of oil pollutants,water,and soil temperature,and for establishing a waterheat-mass transport model in frozen soils.

关键词： Freeze-thaw action Oil movement soil temperature Unfrozen water content Model test

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Thermal and Mechanical Analysis of Ground Freezing Method Applied to Subway Tunnel

Thermal and Mechanical Analysis of Ground Freezing Method Ap...

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第八届国际冻土工程会议

作者： shuangyang li Shujuan zhang {3. Erxiang Zhao (state key laboratory of frozen soil engineering cold and arid Regions environmental and engineering research institute chinese academy of sciences lanzhou gansu 73.000 china.

＜正＞Although controlled ground freezing for construction and mining application has been in use for more than several decades,the literatures concerning about this aspect have mainly concentrated on engineering technique and indoor test instead of theoretical calculations and analyses up to *** order to provide theoretical reference for engineering practice,in this paper,a subway tunnel in Guangzhou,constructed by employing ground freezing method as an auxiliary engineering method,is taken as an example to analyze thermal and mechanical states of soils and linings during tunnel *** first,based on the governing differential equations of the transient temperature field with phase change and heat of hydration of cement,the temperature fields at every excavation stage are computed and analyzed by using finite element ***, according to the distribution feature of the temperature field at every excavation stage and corresponding mechanical parameters decided by this temperature field,the stresses and settlements of soils during corresponding excavation stage are also analyzed through using creep constitutive model for frozen soil and elastoplastic constitutive model for unfrozen *** last,the safety of frozen earth wall is evaluated by applying long-term strength equation of frozen *** results show that,if ground freezing method is used to constructed subway tunnel,the surface settlements will be controlled effectively.

关键词： ground freezing method tunnel temperature field stress settlement

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Discussion on possibilities of taking ground ice in permafrost as water sources on the Qinghai-Tibet Plateau during climate warming

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research in cold and arid Regions 2009年第4期1卷 322-328页

作者： JiChun Wu,Yu Sheng,QingBai Wu,Jing li,XiuMin zhang state {3. laboratory of frozen soil engineering,cold and arid Regions environmental engineering research {13.,chinese academy of sciences,lanzhou,gansu 73.000,china. state key laboratory of {3. soil engineering Cold and Arid Regions Environmental Engineering Research Institute Chinese Academy of Sciences cold and arid Regions environmental and {3. research institute Chinese Academy of Sciences

Large amounts of ground ice are born with permafrost on the Qinghai-Tibet *** of permafrost resulted from the climate warming will inevitably lead to melting of ground *** water released from the melting ground ice enters hydrologic cycles at various levels,and changes regional hydrologic regimes to various *** to difficulties in monitoring the perma-frost-degradation-release-water process,direct and reliable evidence is *** accumulative effect of releasing water,however,is remarkable in the macro-scale hydrologic *** the basis of the monitoring results of water-levels changes in some lakes on the Qinghai-Tibet Plateau,and combined with the previous results of the hydrologic changing trends at the regional scale,the authors preliminarily discussed the possibilities of the degrading permafrost on the Qinghai-Tibet Plateau as a potential water source during climate warming.

关键词： climate warming thawing permafrost melting ground ice potential water source

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Current developments of research on permafrost engineering and cold region environment:a report of the 8^(th) International Symposium on Permafrost engineering

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research in cold and arid Regions 2010年第2期2卷 93-103页

作者： FuJun Niu 1,2,GuoYu li 1,ShuPing Zhao 1,ShuJuan zhang 1,YongGuo Zhao 2,HuiJun Jin 1 1.state {3. laboratory of frozen soil engineering,cold and arid Regions environmental and engineering research {13.,chinese academy of sciences,lanzhou,gansu Province 73.000,china.2.{3. laboratory of Highway Construction and Maintenance Technology for Permafrost Regions of Ministry of Communications,CCCC First Highway Consultants Co.,Ltd.,Xi’an,Shaanxi Province 710068,china state key laboratory of {3. soil engineering Cold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of ScieneesLanzhouGansu Province 730000China key laboratory of Highway Construction and Maintenance Technology for Permafrost Regions of Ministry of Communications CCCC First Highway Consultants Co.Ltd.Xi'anShaanxi Province 710068China state key laboratory of {3. soil engineering Cold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of ScieneesLanzhouGansu Province 730000China key laboratory of Highway Construction and Maintenance Technology for Permafrost Regions of Ministry of Communications CCCC First Highway Consultants Co.Ltd.Xi'anShaanxi Province 710068China

The Eighth International Symposium on Permafrost engineering was held in Xi’an,china.October *** major topics discussed in the symposium included:permafrost engineering (involving design,construction and evaluation);mitigation of frost hazards in the regions affected by seasonally {3. ground;properties of {3. soils,model development and their applications;frost hazards and periglacial environments in mountain and plateau regions;climatic,environmental and cryospheric changes;and permafrost hydrology,cold regions water resources and land *** papers submitted to the symposium and lectures during the meeting represented some new developments of research on cold region engineering and *** we summarized the works of the symposium in topics including:Permafrost engineering;General geocryology;Properties of {3. soils:model development and their applications;And climatic,environmental and cryospheric *** the symposium,the attendees pointed out that future studies should pay more attention to theoretical study and engineering mechanism study,and also on interaction between climate change and cold region environments and their engineering affects.

关键词： the 8th symposium permafrost engineering cold region environment summarizing

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景电灌区次生盐渍化土壤冻融特征

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土壤学报 2002年第4期39卷 512-516页

作者：张立新徐学祖韩文玉北京师范大学遥感与GIS研究中心资源与环境科学系北京100875 中科院寒区旱区环境与工程研究所冻土工程国家重点实验室兰州730000 甘肃省景泰县水利局景泰730400

通过对景电灌区一个冻融周期的现场观测,发现盐渍化土壤冻结期缩短,冻结深度减小,冻结起始位置不是地表,而是位于地表以下某个深度,这导致在冻结发展期间有两个冻结锋面出现,使水热盐动态更为复杂。

关键词：景电灌区次生盐渍化土壤冻融特征

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Application study of the awning measure to obstruct solar radiation in permafrost regions on the Qinghai-Tibet Plateau

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research in cold and arid Regions 2012年第2期4卷 121-126页

作者： WenJie Feng ZhiZhong Sun Zhi Wen GuoYu li Ze zhang WenBing Yu state key laboratory of {3. soil engineering Cold and Arid Regions Environmental Engineering Research InstituteChinese Academy of SciencesLanzhouGansu 730000China

With globe warming, road safety will change dramatically, especially within the Qinghai-Tibet Plateau permafrost regions. Because of higher elevation and better almospheric transparency, the Qinghai-Tibet Plateau has stronger radiation than other regions, which can change the daily variation of ground surface temperature on the Plateau. The awning measure （shading board） is one of the actively protected permafrost measures, which was adopted along the Qinghai-Tibet railway and highway and the Qing-Kang Highway in china. Field test results show that embankment surface month mean net radiation is 60-13. W/m2, but the value is below 20 W/m2 under the shading board, and the reducing level of naRn-al net radiation is 80%-90%. The shading board reduced the heat flow entering into the embankment by 80%,90% or more, with heat entering into the soil on the common embankment, but emitting from the embankment under the shading board. At the same time, ground surface temperature under the shading board is 6-8 ℃ lower than the exposed embankment. Test results show that the shading board measure can rapidly and effectively reduce net radiation and heat flow into the embankment, decrease embankment surface and interior temperature, effectively delay increase rate of soil temperature under globe warming, ensure stabi{3.ty and safety of the embankment, and guarantee unblocked road projects in cold and permafrost regions.

关键词： permafrost sunshading (awning) measure embankment net radiation heat flow

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Characteristics of Permafrost along Highway G214 in the Eastern Qinghai-Tibet Plateau

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Journal of Mountain Science 2015年第5期12卷 1135-1144页

作者： SHENG Yu CAO Yuan-bing li Jing WU Ji-chun CHEN Ji FENG Zi-liang state key laboratory of {3. soil engineering Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences

The characteristics of the permafrost along National Highway No. 214(G214) in Qinghai province(between kilometer markers K3.0 and K670),including the distribution patterns of permafrost and seasonally frozen ground(SFG), ground ice content and mean annual ground temperature(MAGT), were analyzed using a large quantity of drilling and measured ground temperature data. Three topographic units can be distinguished along the highway: the northern mountains, including Ela Mountain and Longstone Mountain; the medial alluvial plain and the southern Bayan Har *** horizontal distribution patterns of permafrost can be divided into four sections, from north to south: the northern continuous permafrost zone(K3.0-K460),the island permafrost zone(K460-K560), the southern continuous permafrost zone(K560-K63.),and the discontinuous permafrost zone(K63.-K670).Vertically, the permafrost lower limits(PLLs) of the discontinuous zone were 4200/43.5 m, 423./43.0 m,and 43.0/4450 m on the north-facing/south-facing slopes of Ela Mountain, Longstone Mountain and Bayan Har Mountains, respectively. The permafrost was generally warm, with MAGTs between-1.0°C and0°C in the northern continuous permafrost zone,approximately-0.5°C in the island permafrost zone,between-1.5°C and 0°C in the southern continuous permafrost zone, and higher than-0.5°C in the discontinuous permafrost zone. In contrast, the spatial variations in ground ice content were mainly controlled by the local soil water content and *** relationships between the mean annual air temperature(MAAT) and the PLLs indicated that the PLLs varied between-3.3.C and-4.1°C for the northern Ela and Longstone Mountains and between-4.1°C and-4.6°C in the southern Bayan Har Mountains.

关键词： Permafrost characteristics NationalHighway No. 214 (G214) Eastern Qinghai-TibetPlateau Qinghai-Tibet Plateau Temperature

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Effects of freeze-thaw cycle on engineering properties of loess used as road fills in seasonally frozen ground regions,North china

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Journal of Mountain Science 2017年第2期14卷 356-368页

作者： li Guo-yu MA Wei MU Yan-hu WANG Fei FAN Shan-zhi WU Ya-hu state key laboratory of {3. soil engineering Cold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of SciencesLanzhou 730000China

Compacted loess is widely used as fills of road embankments in loess regions of northern ***, densely-compacted loess can satisfy the requirements of embankment strength and postconstruction deformation. However, uneven subsidence, pavement cracks and other related damages can affect the integrity of loess subgrade after several years of operation,and even cause some hazards, especially in North china. where the strong freeze-thaw erosion occurs. In this study, cyclic freeze-thaw tests for both densely and loosely compacted loess samples were performed to determine the variation in engineering properties such as volume, void ratio, collapsible settlement,microstructure, and the related mechanisms were addressed. The experimental results showed that an obvious water migration and redistribution occurred within the samples during freeze-thaw cycles. Ice lenses and fissures could be identified in the upper {3. layers of the samples. After freeze-thaw cycles,the dry densities of the upper layers of samples changed significantly due to strong freeze-thaw erosion. The dry densities decreased for the dense sample and increased for the loose sample. It can be found that dense samples become loose, while loose samples became dense with the increasing number of freeze-thaw cycles. Their related void ratios changed reversely. Both void ratios tended to fall into a certain range, which verified the concept of a residual void ratio proposed by Viklander. The loosening process of densely compacted samples involves the formation of large pores, volume increase and density reduction as well as the related changes in mechanical properties because freeze-thaw cycles may be important contribution to problems of loess road *** effects of freeze-thaw cycles, therefore,should be taken into account in selecting loess parameters for the stability evaluation of road embankment in seasonally {3. ground regions.

关键词： Loess Freeze-thaw cycle Frost heave Thaw settlement Road engineering

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Porosity of crushed rock layer and its impact on thermal regime of Qinghai-Tibet Railway embankment

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Journal of Central South University 2017年第4期24卷 977-987页

作者： liU Ming-hao li Guo-yu NIU Fu-jun liN Zhan-ju liN Zhan-ju state key laboratory of {3. soil engineering Cold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of Sciences School of Resources and Environment University of Chinese Academy of Sciences

It has been proven that crushed rock layers used in roadbed construction in permafrost regions have a cooling effect. The main reason is the existence of large porosity of the rock layers. However, due to the strong winds, cold and high radiation conditions on the Qinghai-Tibet Plateau(QTP), both wind-blown sand and/or weathered rock debris blockage might reduce the porosity of the rock layers, resulting in weakening the cooling effect of the crushed rock layer(CRL) in the crushed rock embankment(CRE) of the Qinghai-Tibet Railway(QTR) in the permafrost regions. Such a process might warm the underlying permafrost, and further lead to potential threat to the QTR's integrity and stability. The different porosities corresponding to the different equivalent rock diameters were measured in the laboratory using water saturation method, and an empirical exponential equation between porosity and equivalent rock diameter was proposed based on the measured experimental data and an important finding is observed in our and other experiments that the larger size crushed rock tends to lead to the larger porosity when arbitrarily packing. Numerical tests were carried out to study impacts of porosity on permafrost degradation and differential thaw depths between the sunny and shady shoulders. The results show that the decrease in porosity due to wind-blown sand or weathered rock debris clogging can worsen the permafrost degradation and lead to the asymmetric thermal regime. In the traditional embankment(without the CRL within it), the largest differential thaw depth can reach up to 3.1 m. The optimized porosity appears in a range from 3.% to 42% corresponding to equivalent rock diameter from 10 to 20.5 cm. The CRE with the optimized porosities can make underlying permafrost stable and 0 ℃ isotherms symmetric in the coming 50 years, even under the condition that the climate warming can lead to permafrost degradation under the CRE and the traditional embankment. Some practical implica

关键词： Qinghai-Tibet Railway crushed rock embankment porosity wind-blown sand permafrost degradation

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