25 October 2002, Volume 24 Issue 5
    

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  • XU Bai-qing, YAO Tan-dong, Chappellaz J.
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 477-483. https://doi.org/10.7522/j.issn.1000-0240.2002.0082
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    Atmospheric CH4 has increased globally since the industrial revolution. However, the Dasuopu ice core record shows that the start time of atmospheric CH4 increase in low-mid latitude in north-hemisphere is 100 a latter than that in Polar Regions. Due to the impacts of anthropogenic CH4 emission, CH4 lifetime and CH4 transport in atmosphere, etc., in the recent 150 a, the annual net accumulation and annual growth rate of CH4 in atmosphere are different in low-mid latitude and in Antarctica. The observed decrease of methane concentration during World War and World War is recorded in the Dasuopu ice core. Comparison reveals that in the middle of the last century anthropogenic CH4 emission has reached its highest limit and then a declining atmospheric CH4 growth rate have been documented since 1945. It is reasonable that the differences of atmospheric CH4 between low-mid latitude and Antarctica since industrial revolution are due to human activities, actions of CH4 in atmosphere and local climate variations in Southeast Asia.
  • REN Jia-wen, QIN Da-he, XIAO Cun-de, SUN Jun-ying, LI Zhong-qin, ZHANG Ming-jun
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 484-491. https://doi.org/10.7522/j.issn.1000-0240.2002.0083
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    Following the International Trans-Antarctic Scientific Expedition, inland traverses for glaciological investigation have been made along a route from Zhongshan Station to Dome A. The shallow cores drilled during these traverses have revealed a 250 year high-resolution record of climatic change in the west Princess Elizabeth Land, i.e. east side of the Lambert Glacier basin. Comparison with the results in west side of the basin shows that the Lambert Glacier valley is an important boundary of climate in East Antarctica. On the whole Antarctica, the ice-core records indicate that the cold period characterized by the Little Ice Age (LIA) is relatively strong in East Antarctica, while it is weak or even contrary in West Antarctica. Again in East Antarctica, some differences between east and west of the Lambert Glacier valley can be still seen. In east, such as Wilkes Land (Law Dome) and north Victoria Land (Hercules Neve), the cold period of LIA is striking, but in west, such as Dronning Maud Land and Mizuho Plateau, it is relatively weak. The Lambert Glacier basin is exceptional, where although the LIA cold period exists, a remarkable high temperature stage around 1850 and the temperature decrease since then are very different from other regions in East Antarctica but quite consistent with a 400year record from a core in an island of north Antarctic Peninsula. This is hard to be explained at present.
  • XIAO Cun-de, QIN Da-he, REN Jia-wen, LI Zhong-qin, WANG Xiao-xiang
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 492-499. https://doi.org/10.7522/j.issn.1000-0240.2002.0084
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    Large-scaled investigation of glaciochemistry in surface snow/ice may not only provide some information on global atmospheric processes, but also lay a solid foundation for rational interpretation of regional differences of palaeo-records in ice cores. Three key regions of the cryosphere, i.e., the Polar Regions as well as High Asia, are selected in this study for contrast study of impurities in surface snow/ice. The studied impurities include: 1) Major ions, such as Na+, Ca2+, Mg2+, Cl-, SO42- and NO32-, 2) Halogen element Br, 3) MSA and SO42-. The sources, seasonality, spatial distribution and their environmental implications are presented. Also, the contribution percentage of various sources to some elements is estimated. Large-scaled glaciochemical investigation reveals some information on global atmospheric processes. The major results can be summarized as follows: Marine aerosol is the major contributor to the glaciochemistry in Antarctic Ice Sheet. The impurities in surface snow at High Arctic may be a mixture of crustal, oceanic and anthropogenic origins. Spatial differentiation of glaciochemistry in Arctic is more complicated than those in Antarctica and High Asia. Compared with Greenland and north Canada, the Central Arctic Ocean is more influenced by the mid-latitudinal air mass, especially in winter and early spring. Ions emitted from open waters (such as shear zones) result in concentration peaks in snow over pack ice of the central Arctic Ocean. In High Asia, continental and regional dusts play an important role in glaciochemical records, but in south margin of the Tibetan Plateau, sea salt contents increase. There are two major atmospheric processes that control the features of glaciochemistry in High Asia, i.e., dust storms in north and monsoon in south of the plateau, and the two processes reach equilibrium around the Tanggula Range. In High Asia the windy season coincides with dry season, and the calm season coincides with precipitation season, which largely determines the seasonal transition of deposition functions (i.e., dry and wet deposition) of impurities into snow. The prevailing sources of the impurities in Central Arctic Ocean are mainly from Eurasia and Northwest America. The concentrations of impurities in surface snow on the Tibetan Plateau are higher in its northern and southern margins than those in the central plateau. Generally, the impurities recorded in surface snow on Antarctica may represent the global background, while those on Arctic may represent the background of the lower to middle troposphere in the north hemisphere, and those on High Asia may represent that of the middle to upper troposphere of the mid-latitudes. Large-scaled investigation of glaciochemistry may reveal some important aspects of global atmospheric processes, rational interpretation of ice records should base on more precise study on the sources, transportation and the air/ice interface processes of impurities.
  • WANG Qing-hua, NING Jin-sheng
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 500-505. https://doi.org/10.7522/j.issn.1000-0240.2002.0086
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    By combining GPS-derived horizontal ice flow velocities with Radio Echo Sounding (RES) data, ice fluxes of 43.95 Gt·a-1 and 26.42 Gt·a-1 were achieved across the LGB Profile and the Profile-A under two horizontal ice flow models concerning grounded ice sheet and floating ice shelf, respectively. The former, 1 700 km long, is the middle section of the Australian Lambert Glacier Basin (LGB) traverse route (from LGB05~LGB69), and the latter, 150 km long, is about 50 km away from the Amery ice front. A net basal melt of 7.8 Gt a-1 from the Amery Ice Shelf and a total net surface balance value of 90 Gt·a-1 or so were worked out, concerning that the whole Lambert Glacier Amery Ice Shelf System was analyzed according to the predecessors. The area encompassed by the above two Profiles is called as LGB Area, which occupies about one half of the net surface balance of the above system, although its area is only about one third of the system. Based on the calculation of mass-balance distribution, it is concluded that both Lambert Glacier Amery Ice Shelf System and LGB Area were in positive mass balance, whilst the upstream area of the System was in negative mass balance.
  • LI Shu-xun, NAN Zhuo-tong, ZHAO Lin
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 506-511. https://doi.org/10.7522/j.issn.1000-0240.2002.0087
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    The change characteristics of the heat exchange between atmosphere and ground surface during the temperature wave propagation downwards, the consuming heat during soil freezing or thawing, the change characteristics of the ground temperature observed in different types of freezing ground, the impact of soil freezing and thawing process on heat exchange between atmosphere and ground surface, and the ground temperature are discussed. According to computation and observation, the following conclusions can be drawn. 1) The soil freezing and thawing process greatly increases the heat exchange between atmosphere and ground surface. The propagation speed of ground temperature attenuates with depth and increasing pressure when phase change is absent. 2) During soil thawing the heat exchange is 3 times more than that without phase change. During soil freezing the heat exchange is 3.5 times more than that without phase change. 3) In seasonally frozen ground regions annual mean ground temperature is mainly dependent on summer ground surface temperature, and in seasonally frozen ground regions annual mean ground temperature is mainly dependent on winter ground surface temperature.
  • HE Yong, QIN Da-he, REN Jia-wen, LI Feng-xia
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 512-516. https://doi.org/10.7522/j.issn.1000-0240.2002.0088
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    On the basis of the carbon isotope analysis of organic matter in the paleosol from the Yuanbao Holocene Profile, the values of δ13C are observed between -28.23 ~ -25.19‰, with the average of -26.88‰. Combining the pollen record, it is found that the higher values of δ13C corresponds to warm and humid climate condition, and the lower values corresponds to cold and arid climate condition, which suggests that the climate change has resulted in the changes in δ13C and vegetation types. Three Holocene stages can be recognized from the variation in the characteristics of δ13C in the Yuanbao Holocene Profile. The Holocene climate features recorded in the profile were similar with those in other places of China. The carbon isotope of organic matter in the paleosol is also suggested as an indicator for climate change.
  • PIHG Chien-lu, ZHAO Lin, WANG Shao-ling, Ronald Paetzold, John Kimble, YE Bai-sheng
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 517-522. https://doi.org/10.7522/j.issn.1000-0240.2002.0089
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    The soil landscape relationship was investigated in the Upper Urumqi River Basin of the Tienshan Mountain Range, Xinjiang, China. Cryosols occurred in glaciated valleys and north-facing toeslopes at elevations above 3 000 m. Most cryosols developed in moraine are Aquiturbels. The microrelief is dominated by earth hummocks, thus the surface organic layers are either discontinuous or broken due to frost action. The Bg horizons are either gleyed or mottled and frost-churned organic matter is common in the lower Bg horizons. Stratified horizons and buried organic or A horizons are also common on gentle sloping or undulating moraines indicating the effects of gelifluction. Reticular structures formed in the lower active layers due to ice lens formation and freeze-thaw cycles. The active layer thickness ranges from 140~200 cm. The organic cryosols (Hemistels) occur in depressions and north-facing toeslopes with an active layer thickness ranging from 90~110 cm. Soils formed on south-facing slopes have a mollic epipedon 20~25 cm thick and a strong brown cambic horizon and are classified as Haplocryolls. The distribution of cryosols is smaller as compared with the extent of permafrost due to the depth requirement of permafrost in cryosol classification. However, the existence of permafrost at greater depth cannot be ignored in land use interpretations.
  • Roger G. Barry
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 523-525. https://doi.org/10.7522/j.issn.1000-0240.2002.0090
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    The cryosphere is an integral part of the global climate system, however, many aspects of the cryosphere have not been fully covered within WCRP. Issues relating to potential changes in the climate cryosphere system become more and more important in order to describes research and coordination initiatives required to integrate fully studies of impact and response of the cryosphere to climate change. The article also indicates the recent progress of CliC, and its future plan.
  • Kenji Yoshikawa, Larry D. Hinzman, Prasad Gogineni
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 526-531. https://doi.org/10.7522/j.issn.1000-0240.2002.0091
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    This research presents a method for permafrost mapping in discontinuous permafrost regions based on equivalent latitude/elevation concept in interior Alaska. In winter months, study site has a strong temperature inversion in air up to 700 m elevation. Air temperature data and the effects of slope, aspect and elevation were used to create an equivalent latitude/elevation model. This model was well correlated with mean annual surface temperature (0.79). In this watershed, the thawing index (It≈ 1 400℃·days) at the ground surface and snow depth do not vary greatly from south facing to north facing slopes. The primary controlled factor that determines the mean annual surface temperature was the winter surface temperature. The permafrost stability is effectively controlled by the freezing index. We determined 37.5% of Caribou-Poker Creeks Research Watershed has unstable or thawing permafrost. At least 2.1% of the permafrost in this watershed may have disappeared in the last 90 years due to climate warming. This method makes it possible to evaluate the permafrost stability in the present, past and future.
  • John Kimble, Sergey Goryachkin
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 532-537. https://doi.org/10.7522/j.issn.1000-0240.2002.0092
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    Many factors, such the great changes of temperature, which will be expected at the high latitudes, increased pressure from humans to extract the natural resources in cold regions, seriously affect the cold environment. Many meetings have been held about the classification of cold soils, ideas and concepts of cold soils. These facilitate the need for developing a database of soils of the circumpolar region. The database can help offering information for potential problems in cold regions and for selecting the best areas for placement of new road and towns.
  • Julia Boike, Alfred Wegener, Olaf Ippisch, Kurt Roth
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 538-543. https://doi.org/10.7522/j.issn.1000-0240.2002.0093
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    Mud boils, classified as non-sorted circles, are a common patterned ground phenomenon of permafrost areas. They typically consist of a bare circle center of cryoturbated soil and are surrounded by vegetation on more stable soil. The objectives are to examine differences in seasonal hydrologic and thermal dynamic across this gradient of cryoturbation, i.e. the region below the organic border and the mud center. We installed instruments in a mud boil at a site close to Ny-Ülesund, Spitsbergen, in September 1998. The bare soil circle center ranges about 1 m in diameter and is surrounded by a vegetated border consisting of a mixture of low vascular plants, mosses and lichens. Fine soil (>95% clay and silt) in the lower part of the profile is overlain by coarser grained material (silt and sand). The grain size distribution also suggests an upwelling of fine material in the center of the circle. Temperature and moisture sensors were installed over a vertical 1 m×1 m profile and hourly data recording started in September 1998. Surface irregularities, as well as variations of grain size and moisture, create a non-uniform thermal and hydrologic dynamic. We qualitatively analyze this dynamic with respect to the mud boil’s physical stability.
  • WU Guang-jian, PAN Bao-tian, GUAN Qing-yu, GAO Hong-shan
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 544-549. https://doi.org/10.7522/j.issn.1000-0240.2002.0095
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    The Shagou loess section, which is situated in the border between the Tibetan Plateau and northwest arid region of China, records the detail of climate changes and desert evolution over the past 0.83 Ma BP. Median grain size and sand content in the L6 loess layer indicate that winter monsoon greatly enhanced and desert extremely expanded at that time. During the MIS16, ice sheets in the Northern Hemisphere extended largely, and the global ice volume reached the Maximum since the mid-Pleistocene climate transition. The expansion of northern Siberian ice sheet also reinforced the Siberian High during MIS16. At the same time, the Maximum glaciation developed in the Tibetan Plateau greatly adjusted the westerly and amplified winter monsoon via the Siberian High. Responding to the maximum of global ice volume, as a climate background, and the Maximum Glaciation in the Tibetan Plateau, as an amplifier of the winter monsoon and westerly, deserts in East China expanded extremely. Global ice volume and the Tibetan Plateau are the two important factors influencing desert evolution among others.
  • WANG You-qing, YAO Tan-dong
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 550-558. https://doi.org/10.7522/j.issn.1000-0240.2002.0096
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    Climate changes recorded in the ice cores are the main parts of palaeoclimatology. The palaeoclimatic records in the ice cores from polar, lower-mid latitudes and tropical regions indicated that the global climate has experienced a series of rapid changes on the timescales of centuries to millennium against the general background of the glacial-interglacial cycle. However, the significant uncertainties remain about the cause, mechanism and the scales of the impact of the abrupt change events, such as DansgaardOeschger events, Heinrich events and Younger Dryas event during the last glacial cycle, and cold and dry events during the last interglacial, which are a series of warmer and wetter events punctuated through the glacial period, cold and dry events among of the interglacial period. In this paper the recent study outcomes are reviewed, and the recent progress in timing, process and mechanism of these climatic change events recorded in the ice cores from different areas during the last glacial-interglacial cycle are shown up.
  • LU An-xin, YAO Tan-dong, LIU Shi-yin, DING Liang-fu, LI Gang
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 559-562. https://doi.org/10.7522/j.issn.1000-0240.2002.0097
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    Glaciers on the Tibetan Plateau play an important role in the earth’s climatic system. Regular survey of glacier change is almost impossible in most parts of the plateau. Remote sensing is a primary technique and becomes the only means in many places. GIS provides an efficient tool to analyze the status and the change of glaciers. In the paper, the Geladandong area, the headwaters of the Yangtze River, was selected as the test area. Glacier variation during the Little Ice Age (LIA) maximum, in 1969 and 2000 were analyzed by means of aerial photos, satellite image, topographical map and the derived digital elevation model (DEM). The results indicate that the glacier area had decreased about 5.2% from the Little Ice Age Maximum to 1969 and had decreased about 1.7% from 1969 to 2000. However, the glaciers seem almost steady in the test area in consideration of glacier number only.
  • JING Zhe-fan, YE Bai-sheng, JIAO Ke-qin, YANG Hui-an
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 563-566. https://doi.org/10.7522/j.issn.1000-0240.2002.0098
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    The Glacier No. 51 is located at the headwaters of the Kuyntun River in the Tianshan mountains, with an area of about 1.48 km2 and the largest length of about 1.7 km, of which the ELA ranges from 3 400 to 4 000 m a. s. l. The flow velocities of the glacier have been surveyed since 1999 by using GPS and traditional technique. The surface velocities were determinate over a period of two years (1999-2001). The largest surface velocity was 3.15 m·a-1. Velocity vectors appear the flow characteristics of a valley glacier. Positional variation of glacier terminus was obtained by comparing maps of 1:50 000 and field observations from 1964 to 1999. It was found that the terminus of the glacier has retreated by about 49 m, with an average rate of 1.4 m·a-1, in the period. It retreated 10.03 m from Aug. 1999 to Aug. 2001, with an average rate of 5.0 m·a-1, showing an intensified retreat.
  • HAN Tian-ding, YE Bai-sheng, JIAO Ke-qin
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 567-570. https://doi.org/10.7522/j.issn.1000-0240.2002.0099
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    This paper analyses the major features of temperature variations in southern and northern slopes of Mt. Tianger in the Tianshan Mountains. The following conclusions are obtained: (1) The temperature warming in the plain outside the mountains is higher than that inside the mountains; the increase range of temperature in the northern slopes is higher than that in the southern slopes. (2) Warm winter is the main fact of climate variation for the recent 40 a (1959-1996). (3) The temperature warming rate is 0.121℃·a·a-1 and 0.0822℃·a-1 in Changji and Korla in January, respectively. In Daxigou at the headwaters of the rümqi River there is less temperature variation.
  • CHEN Tuo, QIN Da-he, HE Yuan-qin, REN Jia-wen, LIU Xiao-hong
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 571-573. https://doi.org/10.7522/j.issn.1000-0240.2002.0100
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    δ13C values in different organs are different. Tree leaves have the lowest, while tree trunks have the highest δ13C value. δ13C also varies with exposure, with a relatively lowest δ13C value in the north. There is an inconsistent trend existing in wood δ13C values of different height along the trunk, suggesting no carbon isotope discrimination during the period of the downward transportation of leaf’s organic compounds. Irrespective of tree height and exposure, wood δ13C values have become lower and lower for the past 60 years.
  • LIU Xiao-hong, QIN Da-he, SHAO Xue-mei, REN Jia-wen, WANG Yu
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 574-578. https://doi.org/10.7522/j.issn.1000-0240.2002.0101
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    Abies spectabibis were sampled in Nyingchi County of Tibet Autonomous Region and their stable carbon isotope ratios were measured from their α-cellulose after cross-dating. δ13C values were corrected for changes in the δ13C of CO2 in the atmosphere and detrend to remove the effects of tree age. Simple linear and multivariate were used to determine the natural and strength of any climatic signal. Comparing the neighboring meteorological data, the response of climatic factors to δ13C was analyzed. The results show that the high frequency vibration of δ13C has something to do with seasonal temperature, precipitation and air relative humidity with a time lag.
  • MA Wei, CHENG Guo-dong, WU Qing-bai
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 579-587. https://doi.org/10.7522/j.issn.1000-0240.2002.0102
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    An active measure of protecting frozen soils, namely cooling foundation, is put forward in order to face the severe challenge of high temperature frozen soil and world warming, and to insure the stability of engineering in cold regions. The feasibility of the measure is analyzed and discussed in the aspects of roadbed of ventilation duct, the ballast revetment and ballast roadbed, the roadbed of heat pipe, the roadbed of awning, development and application of heat preservation materials of thermal semiconductor and application of artificially freezing technology, respectively. It is found that as a technology of actively adjusting and controlling temperature in foundation, the measure is effective in different ranges, able to effectively raise permafrost table and can insure the stability of frozen soil foundation. So, it is a feasible method and can be applied to constructions in cold regions.
  • WANG Zhi-jian, ZHANG Lu-xin
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 588-592. https://doi.org/10.7522/j.issn.1000-0240.2002.0103
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    Permafrost environmental problem is one of the three key technology problems in the construction of the Qinghai-Tibetan Railway. The problem is involved with the engineering quality of the Qinghai-Tibetan Railway and the safety of its operation in the future. It is necessary to deeply study the interaction of railway construction and permafrost environment, in order to provide the railway with technological sustain for its safety operation. Aimed at directing and modifying design, and at ensuring the railway quality, it is required to make a diagnostic study of the climate change in permafrost areas on the Tibetan Plateau, a study of the changing trend of permafrost, and a realistic estimation of the stability of permafrost environment. Thus one can theoretically judge the long-term stability of engineering construction and the resistibility against heat effect. When a shape of structure in design and construction is adopted, its adaptability under rising temperature in the future and its influence on permafrost environment must be thought over. Heat influence on construction must be considered. At present, it is urgent to study the design parameter of ventilation pavement with piece rock, and to study the stability of roadbed under changing temperature, and to forecast the period and intensity of the influence of the heat in construction on permafrost. The integrated effect of other temporary projects, highway, pipeline of petroleum, communication cable is also needed to study. Effectively restricting the negative effect of construction and avoiding the long-term and irreversible influence on permafrost environment are the construction department’s own responsibilities. When the railway in operation in the future, heat will be appeared, influencing on permafrost, which must be earnest treated. The domino effect of environment due to the interaction of permafrost and engineering building must be lucubrated, in order to ensure the railway operating for a long-term in safety especially in permafrost areas.
  • Guy Dore
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 593-600. https://doi.org/10.7522/j.issn.1000-0240.2002.0104
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    The article mainly discusses several essential problems of cold region pavement, including thermal cracking of asphalt concrete, cracking deterioration and heaving, frost heave, seasonal and long term roughness induced by different frost heave, frost heave cracking, bearing capacity loss during spring thaw. The reason for these problems is that cold region pavements are subjected to intense solicitation by climatic and environmental factors. The author offers several models corresponding to the solicitation. Furthermore in conclusion of the article the author indicates future research for cold region.
  • YU Wen-bing, LAI Yuan-ming, NIU Fu-jun, ZHANG Xue-fu, ZHANG Shu-juan
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 601-607. https://doi.org/10.7522/j.issn.1000-0240.2002.0105
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    In this paper the laboratory experimental results of ventilated railway embankment in permafrost regions are presented. The model embankment is 1.00 m high and 5.13 m long at the bottom and 2.13 m long at the top, and the slope is 1:1.5. The environmental temperature of the model embankment is changed according to a sine function T=-3.5+12sin((2π/15)τ), and the wind is about 3.2 m·s-1 at the inlet site of the ventilated duct and about 2.37 m·s-1 at the outlet. The test period is 15 days, including a freezing period of 8.1 days and a thawing period of 6.9 days. Three freezing-thawing cycles are conducted. The filling of the embankment is sandy gravel. The temperature curves of some typical sites of the ventilated embankment are analyzed. The temperature fields of three typical sections (cross-section, the symmetric axis section and section between two of the ventilated ducts) at two different moments (the end of the freezing period and the end of the thawing period) are analyzed too. Results show that at the bottom of the embankment temperature variation is not according to changing air temperature, but temperature near the embankment surface varies with air temperature. Along the wind direction, the distribution of temperature in the embankment is not symmetrical when the freezing period is over, but it is symmetrical when the thawing period is over. Temperature difference at different sites in the ventilated ducts is obvious during the temperature descending in the freezing period. The non-symmetrical distribution of air temperature in the ventilated duct is accordance with the non-symmetrical distribution of soil temperature of the embankment. The slope of the temperature curve is very small at the embankment bottom, where the temperature is close to 0℃.
  • NIU Fu-jun, ZHANG Lu-xin, YU Qi-hao, XIE Qun
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 608-613. https://doi.org/10.7522/j.issn.1000-0240.2002.0106
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    The area of permafrost is 150?104km2km2 on the Tibetan Plateau. Slope instability in permafrost regions is somewhat neglected, and there are few reports on sliding case histories of slope failure in permafrost on the plateau. As the research and evaluate methods for slopes in thawed regions can not simply applied to permafrost regions, it is necessary to pay much attention to slope instability in engineering constructions, such as the Qinghai-Tibetan Railway, which has been claimed to be constructed as a environment conservation project. In fact, to the maintenance of the Qinghai-Tibetan Highway, researchers have pointed out that landslide hazards are very important to engineering activities. Instability of frozen soil slopes in permafrost regions is very important to engineering constructions on the plateau. Based on the achievements that have been obtained, in the paper the main types of landslide in permafrost regions of the plateau are introduced. They include collapse, creep slope, debris flow induced terrace, vegetation layer creeping slope and thawing debris flow. Among them, the last one is most hazardous to environment, vegetation and engineering projects. Landslide of thermal-thawing debris flow is due to excavation, and the natural mechanism of slide is soil strength decreasing or even disappearing when in the case of thawing. Finally, engineering treatment methods for thermal-thawing debris flow are proposed based on its sliding mechanism.
  • WU Qing-bai, ZHU Yuan-lin, LIU Yong-zhi
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 614-617. https://doi.org/10.7522/j.issn.1000-0240.2002.0107
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    The thermal offset and permafrost table temperature are important energy indexes in studying permafrost active layers and frost soil environment. The suitability of the thermal offset and permafrost table temperature model generally adopted abroad is discussed in this paper, and the model is applied to the eight frost soil sections along the line of the Qinghai-Tibetan Highway, where ground temperature is monitored. Calculation indicates that the thermal offset and permafrost table temperature similar model can be used to forecast low temperature permafrost (annual mean ground temperature lower than -1.5℃). However, for high temperature permafrost (annual mean ground temperature higher than -1.5℃) this model is unsuitable.
  • SHENG Yu, ZHANG Lu-xin, YANG Cheng-song, FANG Jian-hong
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 618-622. https://doi.org/10.7522/j.issn.1000-0240.2002.0108
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    The principles of protecting permafrost with thermal-insulating treatment are discussed in this. It is considered that the main effect of thermal-insulation material is to decrease the annual changing range of ground temperature below the material. A test of thermal-insulation treatment is performed in a section of the Qinghai-Tibetan highway, which is located around the pass of the Kunlun Mountains. The observed data of ground temperature under the roadbed, shoulders of the road and natural ground surface shows that the insulating treatment cannot change the endothermic trend due to the building of the highway, but can decrease both temperatures and annual temperature changing range in shallow ground. The permafrost table under the insulation-treated roadbed is higher than that of non-insulation sections. The decrease in annual temperature changing range shows a much great effect of thermal-insulation, the dominant function of the thermal-insulation treatment. In another test section, which is located in Beiluhe region of the Qinghai-Tibetan Railway under building, the observed data show a great temperature difference between the upper and bottom of insulation material. Thermal-insulation effect is being sufficiently performed. It is expected that thermal-insulation treatment greatly decrease the annual changing range of ground temperature and protect permafrost from thawing or delay the thawing trend.
  • YU Qi-hao, LIU Yong-zhi, TONG Chang-jiang
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 623-627. https://doi.org/10.7522/j.issn.1000-0240.2002.0109
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    In order to understand the impact of artificial permafrost table to the subgrade deformation of the Qinghai-Tibetan Highway in degenerating process, three experimental observation fields were set up to measure the deformation of the road being built in south of the Tanggula Range. Measurement of two years shows that, when the artificial permafrost table descending, the deformation of the subgrade, such as frost heaving, thaw settlement, is quite different in some aspects, depending on subgrade structure and permafrost type. In the frozen zone with high ice content, if the road is half-dug and half-filled, the subgrade deformation is the strongest. In the zone with less ice, if the road is a high embankment, the subgrade deformation process is comparative slow and low-grade. The freezing time and thawing time under roadbed is reverse with natural conditions.
  • LIANG Bo, WANG Jia-dong, YAN Song-hong, HUANG Zhi-jun, YANG Quan
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 628-633. https://doi.org/10.7522/j.issn.1000-0240.2002.0110
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    In order to adapt itself to the greater deformation of the earth frost heaving process in permafrost regions, to shorten the construction time and to reduce the time of earth disturbed as soon as possible, a test-constructing site was chosen to do a experiment study about designing and using L-type retaining wall in the section from Golmud to Lhasa of the Qinghai-Tibetan Railway. By analyzing the models of forces upon L-type retaining wall, controlling designing values of earth pressure are confirmed without considering the frost heaving forces, because the filling materials are thicker grains. The relationship between earth pressures and frost heaving forces are initially studied. Through analysis and tests, under the precondition of having not gone through a freezing and thawing cycling period, the following initial conclusions can be drawn. (1) When coarse-grained heat-insulated material is used, several analysis model provided in this paper are entirely feasible to design retaining wall. But the model of sliding along a frozen surface is better. (2) For frost heaving soil, without considering earth pressure to design retaining wall based on frost-heaving force is also feasible. The critical problem is to define frost-heaving ratio. (3) When the measured earth pressure of hypothetical wall-back conforms to general parabola-distribution law, it is suggested that the design and test are reliable. (4) From test results and analysis, it is predicted that as long as the filling is non-frost heaving soil and there is a width enough to keep warm, the influence of frost heaving will decrease to the minimum. Other measurements (including measuring the contact-surface pressure between filling and nature soils) show there is no frost-heaving phenomenon, indicating the validity of heat-insulated material.
  • ZHANG Xi-fa, CHEN Ji, ZHANG Dong-qing
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 634-638. https://doi.org/10.7522/j.issn.1000-0240.2002.0111
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    In the seasonal frost regions, more attention is often paid to frost heave index in the aspect of prevention and cure of roadbed frost damage. Thawing settlement index is rare considered even not. Frost heave test is often used to forecast the heave of field soil. But the lab frost heave test result is difficult to be used to analyze the field condition owing to water migration. Besides water migration, complicated road structure and two-dimension boundary condition often go against the application of lab frost heave test result. Therefore, lab frost heave index is not enough to analyze and estimate road frost damage. However, the thawing settlement sample is the field frozen soil sample whose freezing course is reliable. The damage of roadbed (for example, fissure, frost boiling, etc.) is true. At the basis of above comprehension, according to the roadbed boring survey and field observation in several freeways in Jilin Province from 2000 to 2002, the relation between thawing settlement coefficient and water content, dry density and (W-W0) is statistically analyzed. Finally, examples are given, which are able to demonstrate that the spring roadbed boring survey data and thawing settlement coefficient can be used to estimate field thawing settlement amount and frost heave amount, to analyze the causes of roadbed frost damage and to evaluate frost resistance of road constructing material.
  • YU Shu-chao, SONG Ling, OUYANG Hui, MA Qing-an, XING Hai-feng
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 639-641. https://doi.org/10.7522/j.issn.1000-0240.2002.0112
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    A laboratory model test was carried out to study the lining slate when canals suffered the frost heaving. It was found that the frozen-heaving force acted on the slate was parallel to the slate, a tangential force. The magnitude and positive or negative sign of the force directly relates to the water content of canal-bed soil distributed along the canal cross section. Moreover, frozen restraint between the slate and the underneath frozen soil is an important condition for frost heaving of the slate. Frost heaving may occur when the frozen restraint exists, and vice versa. Analyzing the test results, the conclusive cause of frost failure of a rigid lining slate was found. Base on this analysis, some measures against frost heaving damage to canals were provided.
  • SUN Jiang-min, WANG En-liang, YU Xui-mei
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 642-645. https://doi.org/10.7522/j.issn.1000-0240.2002.0113
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    Heilongjiang Province is situated in the middle-high latitude zone, freeze-up period is more than half a year, mean annual temperature is -5 ℃ to 4℃, the lowest temperature is -52.3 ℃, frozen depth is 1.5 m to 3.0 m, the deepest depth can reach 4 m, ice depth of reservoir usually ranges from 1.0 m to 1.5 m, and the deepest ice sheet is 3.0 m. The main factors for revetment damage of earth-dam of plain reservoir in cold regions are as follows: uneven frost heaving of the underlying soil, ice thrust onto slope due to temperature variation, ice cover moment on revetment due to changing water level in reservoir. Up to now, based on the test results and experience, in Heilongjiang Province, dry pitching and later stone pitching cementation of fissures are not applicable. They cannot resist the damage of frost heaving, ice thrust and ice cover moment. Analyzing the mechanisms of underlying soil frost heaving, ice thrust and ice cover moment on the earth-dam revetment, large smooth and thick packs, anti-frost heaving blanket and rubble concrete are suggested to be plain reservoir revetment.
  • NAN Zhuo-tong, LI Xin, LI Shu-xun
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 646-651. https://doi.org/10.7522/j.issn.1000-0240.2002.0114
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    Architecture design is the foundation of software engineering flow. Different architectures require different data models and corresponding realizing methods. There are two kinds of Architectures applicable to software development under network environment, which are File Server Architecture and Client/Server(C/S) Architecture, and the C/S architecture includes both thin client C/S and thick client C/S. Digital Embankment and Numerical Simulation Platform of the Qinghai-Tibetan Railway system needs complicated GIS function and includes a mass of data, such as normal GIS data, atmosphere, ecology and frozen soil data, and so on. To meet these needs, thick client C/S is chosen. Secondly, based on the need of user, the system structure and the system working flow are described in this. In the vertical layer, C/S Architecture consists of User Services, Business Services and Data Services. Combining User Services and Business Services is called thick client C/S. In the system of Digital Embankment and Numerical Simulation Platform of the Qinghai-Tibetan Railway, the Server charges for data storage and management and the Client realizes all application functions. Further, Client program supplies some linkers, which can connect Final, Arcpad and some specialty program. Thirdly, the system is a large project, which involves multifarious knowledge. The requirement of user can t be realized in one step, which needs the system expandable. The architecture system stated in this paper meets this need through spiral iteration between system developing and user requirements analysis. Finally, in order to realize the architecture, the software requirement and realizing method are described in this paper.
  • MA Ming-guo, WANG Xue-mei, LI Xin
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 652-658. https://doi.org/10.7522/j.issn.1000-0240.2002.0115
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    The creation of the Qinghai-Tibetan Railway Information System not only can directly serve the Qinghai-Tibetan Railway project construction, but also can play an important role to the environment protection around the railway and to the railway carrying and managing after it is set up. The database of the Qinghai-Tibetan Railway Information System has a great deal of data account. Its data items are multitudinous. It also serves the engineering construction directly. The innovation points of this paper mainly embody the application of the following newest technologies. The first is the application of practical GIS conception to design the database. The second is the application of the data warehouse conception and technologies in database integration. The third is the application of the object-oriented technologies. The fourth is using metadata to effectively manage and fast query the data resources. The database design includes data item design, data conception design, data particular design, and data integration design.
  • LI Hai-peng, ZHU Yuan-lin, PAN Wei-dong
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 659-664. https://doi.org/10.7522/j.issn.1000-0240.2002.0116
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    Uniaxial compressive strength tests were conducted on the saturated frozen Lanzhou silt (loess) at various constant strain rates and at various constant temperatures. It is concluded from the test results that: the compressive strength (σf) is very sensitive to temperature (θ) and increases with the temperature decreasing as a power law. Compressive strength is sensitive to strain rate (ε) and increases with strain rates increasing within a certain range of strain rates as a power law. Compressive strength decreases when time to failure (tf) increases, also following a power law. Finally, Compressive strength of frozen silt with higher dry density (γd) is higher than that of frozen silt with lower dry density. The difference between them is mainly influenced by strain rate.
  • YANG Ping, ZHANG Ting
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 665-667. https://doi.org/10.7522/j.issn.1000-0240.2002.0117
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    Based on experiments, this paper deals with the differences of density, dry density, moisture content, saturation degree, porosity ratio, plastic limit, liquid limit, plastic index, liquid index, permeability coefficient and the differences of shear strength, unconfined compression strength, compressibility between original and thawing soil.When soil has suffered thawing, its density, dry density and plastic index decrease slightly, porosity ratio, liquid index increase slightly, and other physical index is constant on the whole. If the soil is clay, its permeability increases greatly, reaching 3~10 times of the original. If it is sand, the permeability less increases. The unconfined compression strength of thawing clay significantly decreases, reaching 1/3~1/2 of the original. To apply the frozen method to municipal rock engineering has bright foreground.
  • QIU Ming-guo, XU Xue-yan, LI Hai-shan, CHANG Xiao-xiao
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 668-671. https://doi.org/10.7522/j.issn.1000-0240.2002.0118
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    According to elastic theory solutions of thick-wall cylinder bearing internal uniform pressure, the expanding stress on lateral surface of a cone pile at the end of elastic stage in frozen silty clay are calculated through analysis of expanding effects of cone pile bearing vertical load. The validity of the formulation is verified on the basis of cone pile model experiments under rapid applied load. Calculated expanding stress value has a good fit with the model pile test value in the end period of elastic stage. In the experiment, ten model piles were tested. The maximum relative error between the experimental and the calculated values is 8.94%, and the average absolute value of all errors is 5.15%. At the same time, expanding stress of cone pile under unfrozen conditions can also be solved.
  • REN Jian-xi, LUO Ying, LIU Wen-gang, LI Xin-hu
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 672-675. https://doi.org/10.7522/j.issn.1000-0240.2002.0119
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    Using a specified loading equipment corresponding to the CT machine, a contrastive study of meso-damage failure mechanism of sandstone under successive loading and unloading confine pressure condition is accomplished by means of CT real-time testing. It is demonstrated that in the process of unloading, failure of rock is paroxysmal.
  • LIU Zeng-li, LI Hong-sheng, ZHU Yuan-lin, PU Yi-bin, LI Hong-yan
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 676-680. https://doi.org/10.7522/j.issn.1000-0240.2002.0120
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    Using an additional damage concept, a relationship has been developed between frozen soil density and CT number of computerized topography (CT), regardless of the initial degree of saturation, so that a calculation model between CT number and inner additional damage is put forward. Thus, the relationship of CT number and gaps, which appear along loading process, can be ascertained. Calculation methods for ascertaining initial damage in specimens are suggestedas follows. Firstly, to prepare a perfect sample without any flaw, and then to detect the CT number of its initial state as H0 Secondly, to calculate CT number H01 of supposedly perfect sample but with difference density, and then to calculate the initial damage value D for samples with flaws. This step has been carried out for two series of frozen soil samples, and additional damage values under loading of one set of saturated samples can be determined.
  • ZHAO Shu-ping, ZHU Yuan-lin, HE Ping, YANG Cheng-song
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2002, 24(5): 681-686. https://doi.org/10.7522/j.issn.1000-0240.2002.0121
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    The dynamic response of frozen soil is very important in the study of the deformation, strength and stability of frozen soil under dynamic loading conditions for engineering design in cold regions. This paper discusses the recent progress in research on the dynamic response of frozen soil from the following three aspects. (1) The influence of various testing conditions on dynamic properties. The dynamic modulus of frozen soil increases with decreasing temperature and increasing frequency, and descends with ascending strain amplitude. The frozen soil with higher value of dynamic modulus has higher value of damping ratio. The damping ratio of frozen soil decreases with decreasing temperature and increasing frequency. (2) The dynamic stress-strain properties and the influence of various testing conditions on dynamic strength. The frequency has little influence on dynamic strength. There is a critical confining pressure σ3c. The dynamic strength increases with increasing confining pressure as σc3c, and dynamic strength decreases with increasing confining pressure as σc3c. (3) The effect of testing conditions on dynamic creep factors and the dynamic creep models. Lower the temperature is, less the failure strain, longer the time to failure and less the minimum creep rate will be. Failure strain and time to failure decrease with increasing frequency and minimum creep rate increases with increasing frequency. When the stress increases, failure strain will increase, time to failure will shorten and minimum creep rate will quicken. The failure strain of frozen soil is independent upon confining pressure, and its average value is about half of that under static loading at the similar test condition. Time to failure and minimum creep rate depend on confining pressure. There is a critical confining pressure σ3c. The value of time to failure is longest and minimum creep rate is least when σc3c. The change tendency of time to failure and minimum creep rate is inverse when σc3c or σc3c.