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| 1 | Permafrost changes and engineering stability in Qinghai-Xizang Plateau显示文摘Climate change and engineering activities are the leading causes of permafrost temperature increase,active layer thickening,and ground-ice thaw,which trigger changes in the engineering stability of embankments.Based on the important research advances on permafrost changes and frozen soil engineering in Qinghai-Xizang Plateau,the changes in permafrost temperature and active layer thickness,their relationships with climate factors,the response process of engineering activities on permafrost,dynamic change of engineering stability of Qinghai-Xizang Railway,and the cooling mechanism and process of crushed-rock layers are discussed using the monitoring data of permafrost and embankment deformation.Finally,solutions to the key scientific problems of frozen soil engineering under climate change are proposed. | WU QingBai NIU FuJun | 2013 | Chinese Science Bulletin2013，58，10： | 43 |
| 2 | Ground-temperature controlling effects of duct-ventilated railway embankment in permafrost regions显示文摘Based on observed data from field-testing embankment of the Qinghai-Tibet Railway, ground-temperature controlling effect of duct-ventilated embankment is studied in this paper.The results show that ventilation ducts can effectively cool the soils surrounding the ducts of the embankment, and the heat budget of the ambient soils in a year shows as heat release. Temperature status of the permafrost below the embankment with ducts buried in the relatively high position is similar to that of the common embankment. The permafrost processes warming all along in the two freezing-thawing cycles when the embankment was constructed. However, the temperature of the frozen soils below the embankment, in which the ducts buried in the relatively low position, rises a little in the initial stage. After that, it cools down gradually. At the same time,ventilation ducts can effectively reduce the thermal disturbance caused by the filled soils. The frozen soils below the common embankment and that with high-posited ducts absorb heat all along in the initial two cycles. While the soils below the embankment with low-posited ducts begin to release heat in the second cycle. This phenomenon proves that the ventilation embankment with low-posited ducts shows efficient temperature-controlling effect. Such embankment can actively cool the subgrade soils and therefore keeps the roadbed thermally stable. | NIU Fujun CHENG Guodong YU Qihao | 2004 | Science China Earth Sciences2004，47，z1： | 16 |
| 3 | The application of auto-temperature-controlled ventilation embankment in Qinghai-Tibet Railway显示文摘Auto-temperature-controlled ventilation embankment is an effective engineering measure for 'cooling roadbed'. Practice proves that this new method can sufficiently make use of natural cold energy. It has the advantages of higher efficiency, better cooling effect and feasibility in engineering practice, and wider application in various environment, etc. And also, it is comparatively cheap in project cost. Through practice in the field for half a year, the testing results show that, with the application of auto-temperature-controlled system, the artificial permafrost table has been raised by 65 cm. The artificial permafrost table was basically at the embankment bottom, and the action of freeze-thaw circle on engineering stability was effectively avoided. In the month with highest ground temperature, in the scope with 1-4 m in depth, including the majority of the embankment and the upper part in the original seasonal layer, the ground temperature decreased by 0.7℃. Through thermal flux calculation in the original seasonal layer, in the month with the maximum thermal flux coming into permafrost, it is found that the thermal flux reduces nearly by half. Coming into the cooling period for nearly a month, the ground temperature in entire auto-temperature-controlled embankment is close to zero, and the foundation is at negative temperature. But in a large region in the embankment and foundation the ground temperature was over 0℃ and varied from 0℃ to 0.39℃ in ordinary ventilation embankment. | YU Qihao CHENG Guodong NIU Fujun | 2004 | Science China Earth Sciences2004，47，z1： | 14 |
| 4 | Acoustic experimental study of two types of rock from the Tibetan Plateau under the condition of freeze-thaw cycles显示文摘Under the condition of freeze-thaw cycles,two types of rocks(granite and andesite),used as slope protection for the Qinghai-Tibet Railway,were tested according to the special climatic conditions in the Tibetan Plateau,and their various damage processes in appearance were carefully observed.Observation results show that damage of andesite was more serious than that of granite.Using an acoustic instrument,ultrasonic velocity was tested.The changing trends of velocity with the number of freeze-thaw cycles were analyzed,and the freeze-thaw cycle damaging the physical and mechanical properties of rocks can be seen.According to the changing trends of ultrasonic velocity with the number of freeze-thaw cycles,mechanical parameters of rocks,such as dynamic elasticity modulus,Poisson's ratio,and dynamic bulk modulus were analyzed.It is found that they all have declining trends as the number of freeze-thaw cycles increases,and in particular,when the cycle number reaches a certain extent,the Poisson's ratio of rocks begins to become negative. | Hua Liu FuJun Niu ZhiYing Xu ZhanJu Lin Jian Xu | 2012 | Research in Cold and Arid Regions2012，4，1： | 10 |
| 5 | Numerical analysis of applying special pavements to solve the frost heave diseases of high-speed railway roadbeds in seasonally frozen ground regions显示文摘The Haerbin-Dalian Passenger Dedicated Line is the first high-speed railway constructed in the seasonally frozen ground regions of northeastern China. Frost heave diseases occurred in the first winter of its operation(between October 2012 and January 2013), and frost heave was observed mainly in the roadbed fills that were considered not susceptible to frost heave. This paper proposes applying two special pavements — black pavement and insulation-black pavement — to improve the thermal regime of the roadbed. Three numerical models of the roadbed temperature field were built based on the field conditions of the Changchun section(D3K692+840 to D3K692+860). The results show that:(1) Compared with cement pavement, black pavement and insulation-black pavement could reduce the freezing index at the roadbed surface by 37% and 64%, respectively, which could influence the maximum frozen depth;(2) the maximum frozen depths under the black pavement and insulation-black pavement were respectively 1.3–1.4 m and 1 m. Compared with cement pavement, they could reduce the maximum frozen depth by 0.4 m and 0.7–0.8 m, respectively, which would reduce the permitted amount of frost heave by 4 mm and 7–8 mm, which would meet the deformation limit established by the Code for Design on Special Subgrade of Railway;(3) the freezing periods of the black pavement and the insulation-black pavement were, respectively, approximately four months and two months. Compared with cement pavement, they could reduce the freezing period by approximately 19 days and 40 days, respectively, and delay the initial freezing time by 9 days and 18 days; and(4) compared with cement pavement, black pavement and black-insulation pavement could reduce the frozen areas of roadbeds in the cold season, which suggests that these two special pavements could provide better thermal stability for roadbeds. | Chang Yuan FuJun Niu QiHao Yu XinBin Wang Lei Guo YanHui You | 2015 | Research in Cold and Arid Regions2015，7，4： | 5 |
| 6 | Modeled response of talik development under thermokarst lakes to permafrost thickness on the Qinghai-Tibet Plateau显示文摘Permafrost thickness under identical climates in cold regions can vary significantly because it is severely affected by climate change, topography, soil physical and thermal properties, and geothermal conditions. This study numerically investigates the response of ground thermal regime and talik development processes to permafrost with different thicknesses under a thermokarst lake on the Qinghai-Tibet Plateau. On the basis of observed data and information from a representative monitored lake in the Beiluhe Basin, we used a heat transfer model with phase change under a cylindrical coordinate system to conduct three simulation cases with permafrost thicknesses of 45 m, 60 m, and 75 m, respectively. The simulated results indicate that increases in permafrost thickness not only strongly retarded the open talik formation time, but also delayed the permafrost lateral thaw process after the formation of open talik. Increasing the permafrost thickness by 33.3% and 66.7% led to open talik formation time increases of 83.66% and 207.43%, respectively, and resulted in increases in the lateral thaw duration of permafrost under the modeled thermokarst lake by 28.86% and 46.54%, respectively, after the formation of the open taliks. | Feng Ling QingBai Wu FuJun Niu TingJun Zhang | 2014 | Research in Cold and Arid Regions2014，6，6： | 3 |
| 7 | In-situ testing study on convection and temperature characteristics of a new crushed-rock slope embankment design in a permafrost region显示文摘For the purpose of enhancing air convection and controlling solar radiation, a new crushed-rock slope embankment design combined with a sun-shade measure is proposed. A newly designed embankment was constructed in the Tuotuohe section of the Qinghai-Tibet Railway and a field-testing experiment was carried out to determine its convection and temperature characteristics. The results show that distinct air convection occurred in the crushed-rock layer of the new embankment, especially in cold seasons, which was enhanced when it flowed upwards along the slope. This preliminarily indicated that the new design of the embankment slope was good for reinforcing air convection in the crushed-rock layer. The frequent fluctuations of the convection speed and the environmental wind speed were in good agreement, suggesting that the convection in the crushed rock primarily came from the ambient wind. It was also preliminarily determined that the new embankment had a better cooling effect and sun-shade effect for decreasing the temperature of the embankment slope compared with a traditional crushed-rock slope embankment, and the mean temperature difference between them was up to 1.7 °C. The mean annual temperature at the bottom boundary of the crushed-rock layer was obviously lower than that at the top boundary, and heat flux calculation showed that the shallow soil beneath the embankment slope was weakly releasing heat, all of which indicated that the new embankment slope design was beneficial to the thermal stability of the embankment. This study is helpful in providing some references for improved engineering design and maintenance of roadbeds in permafrost regions. | MingHao Liu FuJun Niu JianHong Fang ZhanJu Lin Jing Luo GuoAn Yin | 2014 | Research in Cold and Arid Regions2014，6，4： | 3 |
| 8 | The Origin of the 2008 Wenchuan Earthquake Determined by the Analysis on the Active Longmenshan Nappe in Terms of Rockmass Mechanics显示文摘On 12 May 2008, the magnitude 8.0 Wenchuan Earthquake occurred along the Longmen Shan nappe, Sichuan, China. This devastating earthquake led to a heavy death toll of greater than 80,000. The seismic origin of this earthquake is currently hotly debated. We suppose that it is a special type of intraplate earthquake called an active-nappe-type earthquake. Using a holistic methodology, incorporating rockmass structure cybernetics and Byerlee's law, we present a comprehensive study on the geological origin of macroseisms in the Longmen Shan area and the seismic origin of the 2008 Wenchuan earthquake. Previous studies of neotectonic activity indicate that the Longmen Shan nappe moves at a rate of 1~3 mm/yr, due to horizontal compressive stress from the Tibetan Plateau. The difference between movement rates in the Bayankala block, Longmen Shan nappe and Sichuan Basin cause slow shear stress and strain accumulation in the Longmen Shan nappe. It is exhibited a relatively simple linear relations for the shear strength and the buried depth of the structural planes, and the detachment layer of the nappe has a higher shearing-sliding strength compared to the overlying fault planes and the underlying ductile shear belts, thus making it more prone to stick-slip deformation. Therefore, the detachment layer was the main section responsible for the Wenchuan earthquake. The initial rupture burst in the detachment layer under the Yingxiu-Beichuan fault, the rupture area nearly 1.4454 × 104 km2,encompassed the cross point of the Yingxiu and the Anxian-Guanxian faults with the detachment layer, then caused the Yingxiu-Beichuan and Anxian-Guanxian faults took an active part in this earthquake, so this earthquake might consist of three chain-like earthquake stages, totally increasing the duration of this earthquake an unusually large amount, to 120 s. The focal depth spanned range of 10-20km,consistent with the observed result of this focal depth by several agencies. | YAN Zhixin MA Guozhe YUAN Binxiang NIU Fujun | 2012 | Journal of Mountain Science2012，9，3： | 2 |
| 9 | Three-dimensional nonlinear analysis for temperature characteristic of ventilated embankment in cold permafrost region 显示文摘 | Lai Yuanming Wang Qiusheng Niu Fujun | 2004 | Cold Regions Science and Technology2004，38，23： | 1 |
| 10 | Dating of two thermokarst lakes in Beiluhe Basin, Qinghai-Tibetan Plateau显示文摘Most of the thermokarst lakes are spread appreciably in Beiluhe Basin,Qinghai-Tibet Plateau,China,where ice-rich permafrost exists.Two typical thermokarst lakes with differing area and depth were examined to ascertain their age.We obtained lake-bottom samples of 50 cm length from lake BLH-A and 25 cm length from lake BLH-B.Environmental 137 Cs and 210 Pb and radiocarbon age dating techniques were applied to the 50 cm and 25 cm samples,respectively.The results indicate that the initiation of BLH-A is about 800–900 a B.P.,and approximately 1,450±30 a B.P.to 2,230±30 a B.P.for BLH-B.These results will provide scientific bases for sedimentological study and thermokarst activity in Beiluhe Basin. | ZhanJu Lin FuJun Niu Jing Luo MingHao Liu GuoAn Yin | 2014 | Research in Cold and Arid Regions2014，6，5： | 1 |
| 11 | Three-Dimensional Nonlinear Analysis for Temperature Characteristic of Ventilated Embankment in Permafrost Regions 显示文摘 | Lai Yuanming Wang Qiusheng Niu Fujun | 2004 | Cold Regions Science and Technology2004，38，： | 1 |
| 12 | Applica- tion of roadbed cooling approach in Qinghai-Tibet rail- way engineering显示文摘 | Cheng Guodong Sun Zhizhong Niu Fujun | 2008 | Cold Regions Science and Tech- nology2008，53，： | 1 |
| 13 | Experimental and numerical investigation on temperature characteristics of high-speed railway’s embankment in seasonal frozen regions显示文摘 | Hua Liu Fujun Niu Yonghong Niu Zhanju Lin Jiahao Lu Jing Luo | 2012 | Cold Regions Science and Technology2012，，： | 1 |
| 14 | Experimental and Numerical Investigation on Temperature Characteristics of High-Speed Railway's Embankment in Seasonal Frozen Regions 显示文摘 | LIU Hua NIU Fujun NIU Yonghong | 2012 | Cold Regions Science and Technology2012，81，： | 1 |
| 15 | Study on Thermal Regime of Roadbed-Culvert Transition Section along a High Speed Railway in Seasonally Frozen Regions 显示文摘 | LIU Hua NIU Fujun NIU Yonghong | 2014 | Cold Regions Science and Technology2014，，： | 1 |
| 16 | A Potential New Frost Heave Mechanism in High-Speed Rail- way Embankments显示文摘 | SHENG Daichao ZHANG Sheng NIU Fujun | 2014 | Geotechnique2014，64，2： | 1 |
| 17 | Cooling effects study on ventilated embankments under the influence of the temperature differences between the sunny slopes and the shady slopes显示文摘 | Zhang Kun Dongqing Li Niu Fujun Mu Yanhu | 2010 | Cold Regions Science and Technology2010，，2： | 1 |
| 18 | Application of roadbed cooling approach in Qinghai-Tibet railway engineering显示文摘 | Cheng Guodong Sun Zhizhong Niu Fujun | 2008 | Cold Re- gions Science and Technology2008，53，： | 1 |
| 19 | Characteristics of thermokarst lakes and their influence on permafrost in Qinghai–Tibet Plateau显示文摘 | Fujun Niu Zhanju Lin Hua Liu Jiahao Lu | 2011 | Geomorphology2011，，3： | 1 |
| 20 | Three-dimensional nonlinear analysis for temperature characteristic of ventilated embankment in permafrost regions显示文摘 | Yuanming Lai Qiusheng Wang Fujun Niu Kehua Zhang | 2004 | Cold Regions Science and Technology2004，，2： | 1 |
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