25 August 1997, Volume 19 Issue 3

    

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  An Observation and Discussion on the Physical Processes at Ice-Rock Interface

  Cui Zhijiu, Xiong Heigang, Liu Gengnian

  JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1997, 19(3): 193-201. https://doi.org/10.7522/j.issn.1000-0240.1997.0029

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  It was found that: (1) Striae are larger and more closely spaced at the centers of U-shaped valleys, but decrease towards the sides. Whale backs occur near the middle of U-shaped valleys, whereas roches moutonnees are found along the valley sides. Thus a U-shaped valley can be divided into a highly abraded center part and weakly abraded but highly quarried side parts. (2) On the longtitudinal section of cross-walls, there are roches moutonnees, whale backs, and highly abraded shear fissures with an angle below 20? on the stoss side. On the lee side, extension fissures with an angle larger than 40? to the horizontal surface appear. Along a U-shaped valley longtitudinal shear fissures appear on the compression sites and extension fissures appear on the tension site. This phenomenon reflects the fact that the glacier and the bed have very uniform mechanical properties. That is to say, where the glacier forms shear faces, shear fissures appear on the underlying bed. and when the glacier forms extension faces, tension fissures appear on the underlying bed and when the glacier forms extension faces, tension fissures appear on the bed. This obviously shows that cold-based glaciers have unique movement characteristics which are not possessed by the other transporting agents, because the freezing-based glacier may tend to merge into an organic whole with the underlying bed.
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  A Steady-state Analysis of Ice Temperature in the Guliya Ice Cap, West Kunlun Mountains

  Huang Maohuan

  JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1997, 19(3): 202-206. https://doi.org/10.7522/j.issn.1000-0240.1997.0030

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  A borehole, 309 m in depth, was made at 6 070 m a s l. on the Guliya Ice Cap in the West Kunlun Mountains, of which in the upmost 200 m ice temperature was measured A steady-state analysis of the measured data reveals a great temperature gradient within the ice cap and the melting point appearing at the bottom. The geothermal flux is calculated to be 112 mW/m², which is coincident with the idea that the Tibetan Plateau is a high geothemal area.
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  Summer Temperature Rise Quantified from the Change of the Glacier No 1 at the Source of Urumqi River in the 20th Century

  Wang Ninglian, Liu Shiyin

  JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1997, 19(3): 207-213. https://doi.org/10.7522/j.issn.1000-0240.1997.0031

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  History of glacier fluctuation is an important way to reveal climate change However, almost all results of climate change derived from glacier fluctuation were qualitative in the past In this paper, an attempt is made to reveal climate change by analysing glacier fluctuation quantitatively, and from the change of Glacier No 1 at the source of Urumqi River in the Tianshan Mts , it is found that summer temperature has risen about 0 23～0 25℃ in this source area since the beginning of this century Meanwhile, climate sensitivity of the glacier under its different lengths is discussed
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  The Features of Hydrological Processes in the Dongkemadi River Basin, Tanggula Pass, Tibetan Plateau

  Zhang Yinsheng, Yao Tandong, Pu Jianchen, Xiao Cunde, Kang Shichang, Hou Shugui, T. OHTA, H. YABUKI

  JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1997, 19(3): 214-222. https://doi.org/10.7522/j.issn.1000-0240.1997.0032

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  Based on the measeurement from May to September 1993 in the Dongkemadi River Basin, Tanggula Pass, Tibeten Plateau, the hydological features are analysed in this paper The amount of precipitation is quite different under different types of weather processes which controlled by plateau monsoon circulation of the atmophere; precipitation in the study region mainly occurs in the period from June to August; the catch ratio of stantard raingauge, comparing to Tretyakov raingauge, is low, and the precipitation correction is lower than that in the Tianshan Mts The evaporation is high and takes 37% for outgoing of water balance; the soil evaporation relates well with water evaporation and soil water content The mean runoff coefficient is 0.63; the mean runoff modulus is 26 L/(s·km²) The water of glacier ablation takes an important role in the discharge of the whole basin, accounting for 49% The ablation runoff mainly occurs from the beginning of July to the beginning of September, that not only relates with air temperature and aslo with the albedo on the glacier.
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  The Preliminary Study of the Features of the Spatial and Temporal Distribution of Surface Water Resources and Their Variation in the Northern Xinjiang

  Yuan Yujiang, Hu Liequn, Li Jiangfeng

  JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1997, 19(3): 223-230. https://doi.org/10.7522/j.issn.1000-0240.1997.0033

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  In this paper, firstly we analyse the features of the spatial and temporal distribution of surface water resources in the Northern Xinjiang by use of empirical orthogonal function expansion Secondly on the basis of the researches we have done before, we extend the sequence of the surface water reources in the Northern Xinjiang from 250 to 412 years, and propose the conditions for combining two sequences that come from different tree-ring chronologies into one sequence At last we analyse the features of abrupt and gradual changing of surface water resources in the Northern Xinjing in the last 412 years
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  Environmental Change in Patchy Permafrost Zone in the South Section of the Qinghai-Tibet Highway

  Wang Shaoling, Zhao Xiufeng

  JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1997, 19(3): 231-239. https://doi.org/10.7522/j.issn.1000-0240.1997.0034

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  Comparing the ground temperature and other investigation data in the 1990’s with those in the 1970’s, it is found that the permafrost degradation and the eco-environmental change is significant in the patchy permafrost zone in the south section of the Qinghai-Tibet Highway The southern limit of permafrost moved northwards about 12 km The area of patchy permafrost decreased 7% The area of swamp land decreased about one third The swamp meadow gradually changes into grassy meadow, and the aquatic plants in lakes and low wet lands were replaced by moderate hygrophilous plants Along with serious degradation of grassland, some lands were desertificated and movable sand dune formed The eco-environment becomes worse gradually
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  Engineering Geological Conditions of Permafrost and Suggestions for Route Selection and Construction of Photocommunication Lines Embedded Along the Qinghai-Xizang(Tibet)Highway

  Wang Jiacheng, Wu Ziwang, Liu Yongzhi, Xu Xiaozu

  JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1997, 19(3): 240-244. https://doi.org/10.7522/j.issn.1000-0240.1997.0035

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  The total length of seasonally and perm anently frozen ground along the Qing hai-Xizang(Tibet)highway is 760 km. The maximum seasonal frost orthaw depth can be estimated by the freezing or thawing index of air temperature. Five types of frozen ground and five grades of frost susceptibility are classified according to water content. Some suggestions of route selection and construction for photo-communication lines embedding are presented.
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  Effect of Confining Pressure on the Dynamic Features of Frozen Silt

  Shen Zhongyan, Zhang Jiayi

  JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1997, 19(3): 245-251. https://doi.org/10.7522/j.issn.1000-0240.1997.0036

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  The relation of stress-strain, dynamic strength, time and vibrating number to failure and rebound dynamic modulus under different confining pressure are discussed based on triaxial compressive tests with constant strain amplitude controlled by constant strain rate in this paper. Confining pressure effect includes effect of enhancing strength and effect of weakening strength. In lower confining pressure the effect of enhancing strength plays a leading role, where dynamic strength increases with increasing of confining pressure; after the confining pressure reaching a limit the effect of weakening strength plays a major role, where dynamic strength decreases with decreasing of confining pressure. As a result, dynamic strength-confining pressure curve is a parabola in shape. One of the principal reasons resulting in above features is that increasing of unfrozen water content and decreasing of basic strength are caused by the drop in freezing temperature of the soil under confining pressure. The deviation of triaxial strength from the Mohr-Coulomb line is in direct proportion to the increased value of unfrozen water content multiplying by the reduced value of basic strength.
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  The Salt Heave of Sulphate Salty Soil Under Different Cooling Rates

  Peng Tiehua, Li Bin

  JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1997, 19(3): 252-257. https://doi.org/10.7522/j.issn.1000-0240.1997.0037

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  The cooling rate has a great effect on the salt heave of sulphate salty soils, with decrease of cooling rate, the salt heave increase in the following power series form, η= AV_T^-B In the tested range A and B increase with increase of salt content and decrease with increase of density
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  Measuring Frozen Soil Displacement with Speckle Photography

  Wu Jianjun, He Lihong, Wang Tingdong, Yu Qihao

  JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1997, 19(3): 258-262. https://doi.org/10.7522/j.issn.1000-0240.1997.0038

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  The measurable range of different speckle photographies is discussed in detail A method for measuring frozen soil displacement is presented, which is a conjoint technology of white light speckle photography, laser speckle photography and microphotography in consideration of the features of frozen soil deformation Experiment shows that it is an effective method for measuring frozen soil displacement within the range of elastic deformation
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  Drilling and Blasting Method of Artificially Frozen Soils

  Ma Qinyong

  JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1997, 19(3): 263-267. https://doi.org/10.7522/j.issn.1000-0240.1997.0039

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  Freezing shaft sinking method is an effective method of sinking deep thick clay strata, and full frozen method is a recommended one. Practices reveal that drilling and blasting method may speed sinking. To enhance the efficiency of drilling and blasting it is necessary to correctly choose drilling equipment, optimum designing parameters of blasting and to perform full face blasting, under the prerequisite of ensuring the safety of freezing pipes.
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  Researches on Preventing Frost Heaving of Box- Separated Gate and Their Application

  Zhu Yujun, Wang Tiegang, Wang Shirong

  JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1997, 19(3): 268-271. https://doi.org/10.7522/j.issn.1000-0240.1997.0040

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  The traditional hydro-engineering gate containing bedding, gate body, step slope and power consumption et al . with a length of more than 60 m is usually suffered frost damage in cold regions. A new type of box-separated gate was designed and set up in 1985 with a discharge of 120 m³/s, and spreaded widely in Northeast, Northwest and North China with a great deal of benefit for preventing frost damage. The performances of the gate are as follows: 1) The main body of the gate designed as bar shaped one, with a length of less than 20% of traditional one which might be affected by frost heaving; 2) All of the foundations is located at the same level covered by enough depth of water which is efficient for preventing frost penentration to their bottom and consquentely the normal frost heaving force under the foundation will surely reduce; 3) The sides of the box were set up as slopes which eliminate the tangential frost heaving force; 4) Box separated gate is affected by symmetrical horizontal frost heaving force which keeps the gate stabilized. The experience shows that the gate can be used in not only cold regions but also non-frost areas, saving a large amount of work and cost.
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  Clathrate Methane and Global Change: A Review

  Jin Huijun, Cheng Guodong

  JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1997, 19(3): 272-279. https://doi.org/10.7522/j.issn.1000-0240.1997.0041

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  Methane clathrate is one of the most important carbon pools in the shallow (<2 km) crust of the earth, containing CH₄-C up to 10 16 kg. Warming by ocean flooding to exposed continental shelves and changes in pressure at depths might destabilize clathrates under the ocean, while ice cap growth stabilizes clathrates under it. The time scales for the two shifts are asymmetrical: the time of methane clathrate fixation as a result of surface cooling is on the order of several tens of thousands of years, while the thermal destabilization of the CH₄ clathrates is set by thermal properties of sediments and on the order of thousands of years. The sensitivity of clathrates to surface changes, the time scales involved, and the large carbon pool of the clathrates indicate that methane clathrate may have played an important role in modifying the composition of the ice age atmosphere: the release of CH₄ and its subsequent oxidation may be responsible for the observed fluctuations in atmospheric CH₄ and CO₂ concentrations during glacial and interglacial periods, which induced the strong feedbacks to climatic systems and enhanced the greenhouse warming at the end of ice ages. Up to now, the clathrate CH₄ feedback mechanisms well explain the glacial-interglacial climate variations, especially the abruptness of the ice age termination and their slow build up. The warming of the arctic permafrost and subsea permafrost and clathrate CH₄ release have been possibly in progress, but the amount of release might be small at present and in the next century. The impacts of the methane clathrate on global warming are extremely complex and highly tentative due to its roughness in carbon estimation, and meditativeness in its feedback mechanisms.
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  Progresses in the Studies of Soil Freezing and Frost Heaving

  Xu Xiaozu, He Ping, Zhang Jianming

  JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1997, 19(3): 280-283. https://doi.org/10.7522/j.issn.1000-0240.1997.0042

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  The international symposium on ground freezing and frost action in soils was hold in lulea university of technology, sweden, on 15～17 April, 1997. The proceedings include 82 papers dealing with ISSMFE work group reports, heat and mass transfer in freezing and thawing soils and rock, frost susceptibility and frost heave, mechanical properties of frozen, thawed and thawing soils and rock, environmental soil freezing, engineering design and case histories. In this paper attention was paid on progresses in the study of soil freezing and frost heaving,design and case histories. In this paper attention was paid on progresses in the study of soil freezing and frost heaving.
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  Determination of the Core Periodicals in Glaciology and Geocryology

  Liu Jingren

  JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1997, 19(3): 284-287. https://doi.org/10.7522/j.issn.1000-0240.1997.0043

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  The core periodicals in glaciology and geocryology are determined by means of abstracts on the basis of “Polar and Glaciological Abstracts”, and are classed by subject. It is found that some comprehensive periodicals of natural sciences, such as “Nature”, “Science”, “Dissertation Abstracts International B: Sciences and Engineering”, are of great significance in glaciology and geocryology. In addition, the developing trends in glaciology and geocryology are also reviewed.