25 November 1995, Volume 17 Issue 4
    

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  • Mourning for Professor zhang Xiangsong
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1995, 17(4): 289-290. https://doi.org/10.7522/j.issn.1000-0240.1995.0040
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  • Distribution of Snow Cover Over the High Asia
    Li Peiji
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1995, 17(4): 291-298. https://doi.org/10.7522/j.issn.1000-0240.1995.0041
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    The snow cover in central high Asia has been the focus of climatologists interests for many decades. A study is presented ot the detailed spatial pattern, seasonal cycle and regionalization of snow cover over the High Asia, by using the best information concerning microwave derived Pentad snow depth charts employing data from SMMR (1978-1987),Operational NOAA digitized weekly snow cover extent charts (1973-1989), in conjuction with daily records of snow depth, density and number of snow cover days at 60 primary synoptic stations (1957-1992).
  • An Evaluation of NOAA/NESDIS Digitized Snow Cover Monitoring in the Tibetan Plateau
    Cao Meisheng
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1995, 17(4): 299-302. https://doi.org/10.7522/j.issn.1000-0240.1995.0042
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    NOAA images for monitoring snow cover in the Tibetan Plateau in 1993/1994 have been analysed and the accuracy of NOAA/NESDIS digitized snow cover data in this region has been evaluated. It is discovered that if a study area in this region includs over NOAA/NESDIS 50 grids, the statistical value using this digitized data will be satisfied with the accuracy of monitoring snow cover extent (%) provided by WCRP.
  • A Traverse Expedition to the Lambert Glacier Basin,Eastern Antarctica
    Ren Jiawen
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1995, 17(4): 303-307. https://doi.org/10.7522/j.issn.1000-0240.1995.0043
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    The Lambert Glacier, feeding into the Amery Ice Shelf, is the largest ice stream in the East Antarctic ice sheet. Preliminary results from recent traverse along a route across its inland accumulation area show that the accumulation rate in this area is very low, not exceeding 150 kg/(m2·a) at most sites. The mean annual temperature ranges from -45℃ to-30℃. Average density of surface 2m snow is around 400 kg/m3. Depth-hoar is seen at many sites with an elevation between 1830 and 2700 m. The surface velocity is generally within 20 m/a. Snow redistribution caused by strong katabatic-wind and sastrugi brings about an uncertainty in the annual-layer identification using 618O profile in low accumulation area.
  • Variation of dδ18O/dT in Precipitation in the Tibetan Plateau
    Zhang Xinping, Yao Tandong
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1995, 17(4): 308-314. https://doi.org/10.7522/j.issn.1000-0240.1995.0044
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    This paper analyses the relations between δ18O and temperature, as well as the synoptic,seasonal and climatic variations of δ18O with temperature, according to the data from Tuotuohe (34°13′ N, 96°26′ E; 4533 m a.s.l.), Delingha (37°22′ N, 97°22′ E; 2981 m a.s.l.) and Xining (36°37′N, 101°46′E; 226lm a.s.l.). The results show that the significance of dδ18O/dT of different time scales is different. Averagely, the long the time scale is,the greater the dδ18O/dT value is.
  • Tensile Strength of Frozen Saturated Loess
    Shen Zhongyan, Peng Wanwei, Liu Yongzhi
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1995, 17(4): 315-321. https://doi.org/10.7522/j.issn.1000-0240.1995.0045
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    Tensile tests on the frozen saturated loess show that their failure is brittle. Shear and displacement of the mineral grain occur and mini-fissures grow on the cross section of the crack. The stress-strain processes of the tensile are classified into three types depending on the load rates i.e.viscoelastic-plastic, viscoelastic and brittle deformation. They may be described by an unitized expression. The features of stress-strain, peak stress, strain and time to failure of frozen saturated loess are also discussed in this paper. The ratio of tensile strength to compressive strength is 0.44-0.63 independently of the temperature and load rate.
  • The Analogic Conditions of Simulation Test of Frozen Soil
    Wang Tingdong, Zhao Xishu, Wu Ziwang, Liu Yongzhi
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1995, 17(4): 322-327. https://doi.org/10.7522/j.issn.1000-0240.1995.0046
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    The analogic conditions applied to model experiment are generally presented in this paper, according to the linear theory of viscoelasticity and satifying the Boltzmann’s principle of superposition and further discussed for creep of frozen soils. Based on these, the formulas for calculating stress, strain, and displacement are obtained, from which the model experimental results can be applied to the relative practical problem.
  • Experimental Stodies of Fracture Toughness KIC for Frozen Soil
    Li Hongsheng, Zhang Xiaopeng, Zhu Yuanling, Peng Wanwei
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1995, 17(4): 328-333. https://doi.org/10.7522/j.issn.1000-0240.1995.0047
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    According to relevant testing methods, 3-point bending specimens are employed. Then we test and study the fracture toughness KIC of frozen soil through experiment, using fracture mechanics theorys. From the experimental results, we learn that water content, temperature and loading rate are the main innuence factors on KIC By analysing the experimental data, a quantitative experession between KIC and main influence factors is obtained.
  • Creep Failure Characteristics of Frozen Sand under Two-step Stress
    Sheng Yu, Wu Ziwang, Miao Lina, Ma Wei
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1995, 17(4): 334-338. https://doi.org/10.7522/j.issn.1000-0240.1995.0048
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    This paper presents a series of creep tests of frozen soil under two-step stress. It is found that the creep failure time under two-step stress increases and the minimum strain rate decreases comparing with those under a single stress, i.e. the first step stress strenghenes frozen soil. At a same applying time of first step stress, the strenghened extent depends on the first step stress. When the first step stress is equal to a critical value, frozen soil is maaimally strenghened.
  • Torsion-Shear Strengths of Frozen Soil under Different Test Methods
    Peng Wanwei, Zhang Changqing, Zhang Jianming
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1995, 17(4): 339-342. https://doi.org/10.7522/j.issn.1000-0240.1995.0049
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    The paper compares the torsion-shear strength of frozen loess with other test results (direct shearing, triaxial-shearing and tension test) on the basis of a series of torsion tests. It is revealed that the shearing strength of frozen soil is not only dependent on the physical properties of soil but also on the test condition and method.
  • Comparisons of the Creep and Crystallographic Properties of Laboratory Prepared Ice with Core Ice
    Gao Xiangqun, T.H.Jacka
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1995, 17(4): 343-349. https://doi.org/10.7522/j.issn.1000-0240.1995.0050
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    An accoant is given of ice deformation experiments in uniaxial compression. Samples studied include isotropic and anisotropic ices, laboratory prepared and from a core drilled near the summit of Law Dome, Antarctica. There are unexplained differences in the Annimum strain rates attained by isotropic ices from the core and from the laboratory. Minimum strain rates for anisotrpic ice are higher than that of isotropic ice provided that the anisotropy is compatible with the stress configuration. The approach to similar tertiary creep rates has been found for antarctic core ice and laboratory prepared ice, associated with the development of tertiary creep. The resultant fabric patterns are the same in both types of ice, the crystal sizes are also similar.
  • Permafrost Change and Stability of Qinghai-Tibet Highway
    Wu Qingbai, Tong changjiang
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1995, 17(4): 350-355. https://doi.org/10.7522/j.issn.1000-0240.1995.0051
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    Climate Warming and human activity bring out a great influence on permafrost along Qinghai-Tibet highway. For example, the temperature of permafrost rises, the thickoness of permafrost eliminate, disconhnuous permafrost retreats toward north and so on. These changes seriously disturb and affect the stability of Qinghai-Tibet highway. Meanwhile, considering these changes and engineering stability, the stability of Qinghai-Tibet highway is divided into six zones: 1) very stable zone; 2) stable zone; 3) basically stable zone; 4) basically stable passing zone, 5) unstable zone; 6)extreme unstable zone.
  • Plotting of Trend Surfaces of Firn Line and Median Altitudes of Glaciers in the Interior Water Systems of the Tibetan Plateau and Their Main Features
    Liu Zongxiang, Xie Zichu
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1995, 17(4): 356-359. https://doi.org/10.7522/j.issn.1000-0240.1995.0052
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    In this paper, firn line and median altitudes of glaciers, and their geographical coordinates in the data base of glacier inventory of the interior water system in the Tibetan Plateau of China are analysed. Applying the plotting function of computer, we get the trend surfaces of firn line and median altitudes of glaciers. A detailed knowledge of glacier features in this region is therefore demonstrated.
  • Recent Progresses in Studies of Ice Flow in China
    Huang Maohuan
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1995, 17(4): 360-370. https://doi.org/10.7522/j.issn.1000-0240.1995.0053
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    In this paper the progresses in theoretical and experimental studies of ice flow which were conducted by Chinese researchers both at home and abroad are briefly reviewed, including grain growth, tertiary creep of anisotropic ice, ice flow under combined compression and shear and difference in now properties of Holocene and wisconsin ice.
  • Present and Development Tendency on Sinking Methods of Artificially Frozen Soils
    Ma Qinyong
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1995, 17(4): 371-374. https://doi.org/10.7522/j.issn.1000-0240.1995.0054
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    A review is made for blasting and sinking mechanized methods of frozen soils. It is found that the velocity of blasting four times as high as of sinking mechanized method. The latter is on trial in China. The present problems of sinking methods are discussed in this paper. At last the paper expounds how to improve the sinking methods. Development tendency of sinking methods of artificially frozen soils is that blasting method will be further improved and developed, and sinking mechanism will be further designed and investigated.
  • Book Review: Mechanisms of Frost Heaving and Salt Expansion of Soils
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1995, 17(4): 377-378. https://doi.org/10.7522/j.issn.1000-0240.1995.0055
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