Land Resources of Cryolithozone and Possible Transformations under Globle Change

Issues about land resources of cryolithozone and their possible transformation under global change conditions we will consider on example of the large region of the Russian Federation-the Republic of Sakha (Yakutia),which is considered as the center of the underground continental glaciation of earth in present conditions.     

Artificially frozen ground and related engineering technology in Japan

Since the 1970's, frozen ground has been developing near the Tokyo Bay area around liquefied natural gas(LNG) inground storage tanks. For disaster prevention purposes, the tanks are constructed below the ground surface. Since the temperature of the liquid stored in the tanks is -162℃ the soil surrounding the tanks freezes. Since this frozen ground has existed for almost half a century, we have permafrost near Tokyo. The development of artificial frozen ground may cause frost heaving, resulting in frost heave forces that may cause structural damage of adjacent LNG in-ground storage tanks.Therefore, the demand for frozen ground engineering increased and consequently we now have advanced technology in this area. Fortunately, we use this engineering technology and artificial ground freezing for civil engineering, especially in big and crowded cities like Tokyo. This paper provides a summary of the testing apparatus, test methods, and assessment methods for frost heaving.     

Deformation behavior of in situ permafrost on the Qinghai-Tibetan Plateau

Creep is an important mechanical behavior of frozen soils, one which can cause many problems for the infrastructures in permafrost regions on the Qinghai-Tibetan Plateau. To access the natural creep properties of in situ permafrost for explaining the engineering instability and predicting long-term deformation, conducting field tests is necessary. The paper reports on a group of plate loading tests we carried out over many years on the Qinghai-Tibetan Plateau. The results show that the ground temperature at the loading plates ranged from-0.29 °C to-3.03 °C, and the mean annual ground temperature increased year by year in a linear fashion. Affected by the ground-temperature variations, two forms of deformation curves, a step-form and a wave-form occurred, depending on the relative extent of settlement in warm seasons and frost heave in cold seasons. Overall, the deformations of permafrost were characterized by settlement. The deformation magnitudes and curve styles of permafrost are different at different locations attributing to the influence of ground temperature and moisture content. Due to the existence of much unfrozen water in warm frozen soils, consolidation resulting from migration of unfrozen water along seepage channels may play a significant role in the settlement of permafrost. The research can provide a credible reference for engineering in the permafrost regions and the numerical computation of settlement.     

Average temperature calculation for straight single-row-piped frozen soil wall

The average temperature of frozen soil wall is an essential parameter in the process of design, construction, and safety management of artificial ground freezing engineering. It is the basis of calculating frozen soil’s mechanical parameters, further prediction of bearing capacity and, ultimately, safety evaluation of the frozen soil wall. Regarding the average temperature of single-row-piped frozen soil wall, this paper summarizes several current calculation methods and their shortcomings. Furthermore, on the basis of Bakholdin’s analytical solution for the temperature field under straight single-row-piped freezing, two new calculation models, namely, the equivalent trapezoid model and the equivalent triangle model, are proposed. These two approaches are used to calculate the average temperature of a certain cross section which indicates the condition of the whole frozen soil wall. Considering the possible parameter range according to the freezing pipe layout that might be applied in actual construction, this paper compares the average temperatures of frozen soil walls obtained by the equivalent trapezoid method and the equivalent triangle method with that obtained by numerical integration of Bakholdin’s analytical solution. The results show that the discrepancies are extremely small and these two new approaches are better than currently prevailing methods. However, the equivalent triangle method boasts higher accuracy and a simpler formula compared with the equivalent trapezoid method.     

Influence of frost weathering on the recession of surfaces of technogenic landforms in Yakutia

The article assesses the influence of permafrost weathering on the rate of destruction of technogenic land forms, as exhibited on as illustrated by the railway embankment of the Amur-Yakut mainline in the Sakha Republic(Yakutia). Studies were carried out on a railway section more than 375 km long. The subsidence rate of the embankment slopes and structural excavations was determined using laboratory methods that simulate various mechanisms of temperature(with a transition through 0 ℃) impact on rocks. For the first time, a quantitative assessment of the influence of cryogenic weathering on the stability of the railway in the region belonging to the northern building-climatic zone is given. For the territory under consideration, embankment rocks were experimentally determined to undergo more than 100 freezing and thawing cycles during a year. Under the existing climatic conditions, cryogenic weathering actively affects the embankment of the railway to a depth of 30 cm. Most of the embankment deformations detected during field observations are due to defects in the integrity of this particular layer. The size of the disintegrating layer of particular types of rock comprising the railway embankment has been established as reaching 10 cm per year. In 5 years following the formation of embankments comprising the upper structure of the railroad tracks, the physical and mechanical properties of rocks, which initially had a tensile strength for uniaxial compression in the range of 40-70 MPa, were reduced by more than 50%. According to the authors, the establishment of regional cryohypergenesis features is universal in nature and can be applied to solving a wide range of tasks related to the assessment and prediction of the degree of cryogenic transformation of rocks having different structural properties.     

Refreezing of cast-in-place piles under various engineering conditions

In the construction of the Qinghai-Tibet Power Transmission Line(QTPTL), cast-in-place piles(CIPPs) are widely applied in areas with unfavorable geological conditions. The thermal regime around piles in permafrost regions greatly affects the stability of the towers as well as the operation of the QTPTL. The casting of piles will markedly affect the thermal regime of the surrounding permafrost because of the casting temperature and the hydration heat of cement. Based on the typical geological and engineering conditions along the QTPTL, thermal disturbance of a CIPP to surrounding permafrost under different casting seasons, pile depths, and casting temperatures were simulated. The results show that the casting season(summer versus winter) can influence the refreezing process of CIPPs, within the first 6 m of pile depth. Sixty days after being cast, CIPPs greater than 6 m in depth can be frozen regardless of which season they were cast, and the foundation could be refrozen after a cold season. Comparing the refreezing characteristics of CIPPs cast in different seasons also showed that, without considering the ground surface conditions, warm seasons are more suitable for casting piles. With the increase of pile depth, the thermal effect of a CIPP on the surrounding soil mainly expands vertically, while the lateral heat disturbance changes little. Deeper, longer CIPPs have better stability. The casting temperature clearly affects the thermal disturbance, and the radius of the melting circle increases with rising casting temperature. The optimal casting temperature is between 2 °C and 9 °C.     

青藏高原地气温差变化及空间分布

The difference between ground soil and air temperature （Ts-Ta） was studied by using the data of ground and air temperature of 99 stations over the Qinghai-Xizang （Tibet） Plateau from 1960 to 2000,and its spatial distribution and time changing tendency have been diagnosed by principal component analysis and power spectral analysis methods. The results show that the values of （Ts-Ta） are the maximum in June and the minimum in December. The first three loading eigenvectors, which reflect the main spatially anomalous structure of （Ts-Ta） over the Qinghai-Xizang Plateau, contain the contrary changing pattern between the northwestern and the southeastern regions, the pattern response of the sea level elevation and the geography, and the pattern response of the distribution of the permafrost. There are four patterns of time evolution including the patterns of monotonous increasing or decreasing trends, the basic stability pattern and the parabola pattern with the minimum value. （Ts-Ta） has a periodic variation about 2 years. According to the spatial distribution of the third loading eigenvectors of （Ts-Ta） over the Qinghai-Xizang Plateau in cold season, the permafrost response region and the seasonal frozen ground response region are identified.     

Analysis about the influence on the thermal regime in permafrost regions with different underlying surfaces

In the last several decades, the underlying surface conditions on the Qinghai-Tibet Plateau have changed dramatically, causing permafrost degradation due to climate change and human activities. This change severely influenced the cold regions environment and engineering infrastructure built above permafrost. Permafrost is a product of the interaction between the atmosphere and the ground. The formation and change of permafrost are determined by the energy exchange between earth and atmosphere system. Fieldwork was performed in order to learn how land surface change influenced the thermal regime in permafrost regions. In this article, the field data observed in the Fenghuo Mountain regions was used to analyze the thermal conditions under different underlying surfaces on the Qinghai-Tibet Plateau. Results show that underlying surface change may alter the primary energy balance and the thermal conditions of permafrost. The thermal flux in the permafrost regions is also changed, resulting in rising upper soil temperature and thickening active layer. Vegetation could prevent solar radiation from entering the ground, cooling the ground in the warm season. Also, vegetation has heat insulation and heat preservation functions related to the ground surface and may keep the permafrost stable. Plots covered with black plastic film have higher temperatures compared with plots covered by natural vegetation. The reason is that black plastic film has a low albedo, which could increase the absorbed solar radiation, and also decrease evapotranspiration. The ＂greenhouse effect＂ of transparent plastic film might effectively reduce the emission of long-wave radiation from the surface, decreasing heat loss from the earth＇s surface, and prominently increasing ground surface temperature.     

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

The Eighth International Symposium on Permafrost Engineering was held in Xi’an,China,October 2009.The major topics discussed in the symposium included:permafrost engineering (involving design,construction and evaluation);mitigation of frost hazards in the regions affected by seasonally frozen ground;properties of frozen soils,model development and their applications;frost hazards and periglacial environments in mountain and plateau regions;climatic,environmental and cryospheric changes;and permafrost hydrology,cold regions water resources and land uses.The papers submitted to the symposium and lectures during the meeting represented some new developments of research on cold region engineering and environment.Here we summarized the works of the symposium in topics including:Permafrost engineering;General geocryology;Properties of frozen soils:model development and their applications;And climatic,environmental and cryospheric changes.During the symposium,the attendees pointed out that future studies should pay more attention to theoretical study and engineering mechanism study,and also on interaction between climate change and cold region environments and their engineering affects.     

毛乌素沙地休耕期砒砂岩的固沙效应研究(英文)

Depended on the analysis of ground snow situation, soil moisture loss speed and soil structure after planting crops of Mu Us Sandy Land remedied with feldspathic sandstone in the fallow period, it is concluded that feldspathic sandstone mixed with sand improved the sand stabilization in the governance of Mu Us Sandy Land in the fallow period. The sandy land remedied with feldspathic sandstone had big snow coverage, 25%–75% higher than normal sand; soil moisture losses slowed down, and moisture content rose by over 3 times; soil structure had been improved, and water stable aggregate content increased by 6.52%–18.04%; survival rate of protection forest increased to 85%; and ground flatness is less than 1%. The above conditions weakened sand rising conditions of Mu Us Sandy Land in the fallow period and formed two protective layers of snow cover and soil frozen layer under cold weather so as to prevent against wind erosion.     

Landscape Mapping Using GIS and Google Earth Data

The process of laboratory compilation of the natural landscape chorological map of one of the uluses (administrative districts) of the Sakha (Yakutia) Republic is presented at a scale of 1:2 500 000. The GIS tools were used to reference thematic cartographic documents to the topographic base of the ulus containing contour lines, elevations and the main river network. The final river network is drawn on the basis of other data sources. A significant role in the subsequent map compilation stages was played by data from the Google Earth website: 2D and 3D images were used to identify floodplains. Units of glacial landforms of foothill areas and the main types of geological and geomorphological units of the ulus were determined using both published data sources and the Google Earth imagery. The map of natural vegetation has been compiled having regard to the humidity conditions and the vertical zonation of the climate and soils. The digital map layers in GIS were gradually combined into the synthetic natural landscape map of the ulus, and the identified natural landscape units were also incorporated into the regional classification of the landscapes of Siberia. It is established that the hierarchical system of natural landscapes of the ulus differentiates three levels of classification: high (the landscapes are differentiated with respect to their geographical location into the landscapes of lowlands and high mountains), intermediate (the differentiation of the landscapes with respect to the genesis and topography dissection in a relevant climatic zone) and low (the natural landscapes are determined by a combination of vegetation covering the type of soil that developed on a given geological substrate).     

The rare-earth metals industry of Russia: Present status,resource conditions of development

The importance of rare-earth metals in the advancement of scientific and technological progress, the geographical features characteristic for the development of the rare-earth sector in the world and in Russia, and the raw-material base of its development in Russia are considered. Emphasis is placed on the special significance of the Tomtorskii composite rare-metal/rare earth deposit in the Sakha Republic (Yakutia).     

Geoecological approach to infrastructural development of hiking trails in federal-level SPNA (as exemplified by the Baikalskii nature reserve)

The comprehensive utilization of the technique for substantiating the promotion of hiking tourism, with emphasis on infrastructural development to ease access to recreational sites for different categories of visitors. The goal of using specialized hiking trails is to furnish a means of acquiring a familiarity with the unique landscapes of the Khamar-Daban mountain range. The technique contains four consecutive stages, and their implementation is illustrated in terms of the model territory. An analysis is made of the socioeconomic and geoecological characteristics of the Baikalskii Biosphere Reserve, which, together with landscape assessment, serves as a basis for the generation of the zoning map for possibilities and restrictions as regards the promotion and development of hiking tourism. A zoning is provided, which takes into consideration the possibilities of hiking tourism, based on assessing a territory’s transport accessibility, estimating the cost of preparing a trail of each class, and on the geoecological characteristics of landscape. The map that identifies seven zones of different-intensity transformation of the territory for an integral development of hiking tourism is used in making recommendations for the preparation of hiking trails in the Baikalskii Nature Reserve. The landscapes are combined into zones according to the degree of suitability for the construction of trails of different classes. The algorithm for preparation of trails consisting of 10 consecutive stages (three stages of planning, and seven stages of preparation) is applied for a number of linear features. The most suitable classes of preparation are indicated for these trails, in accordance with the characteristics of landscapes and engineering restrictions within their boundaries.     

Studies on frozen ground of China

Permafrost in China includes high latitude permafrost in northeastern China, alpine permafrost in northwestern China and high plateau permafrost on the Tibetan Plateau. The high altitude permafrost is about 92% of the total permafrost area in China. The south boundary or lower limit of the seasonally frozen ground is defined in accordance with the 0 oC isothermal line of mean air temperature in January, which is roughly corresponding to the line extending from the Qinling Mountains to the Huaihe River in the east and to the southeast boundary of the Tibetan Plateau in the west. Seasonal frozen ground occurs in large parts of the territory in northern China, including Northeast, North, Northwest China and the Tibetan Plateau except for permafrost regions, and accounting for about 55% of the land area of China. The southern limit of short-term frozen ground generally swings south and north along the 25o northern latitude line, occurring in the wet and warm subtropic monsoon climatic zone. Its area is less than 20% of the land area of China.     

中国冻土研究进展

Permafrost in China includes high latitude permafrost in northeastern China, alpine permafrost in northwestern China and high plateau permafrost on the Tibetan Plateau. The high altitude permafrost is about 92% of the total permafrost area in China. The south boundary or lower limit of the seasonally frozen ground is defined in accordance with the 0 ℃ isothermal line of mean air temperature in January, which is roughly corresponding to the line extending from the Qinling Mountains to the Huaihe River in the east and to the southeast boundary of the Tibetan Plateau in the west. Seasonal frozen ground occurs in large parts of the territory in northern China, including Northeast, North, Northwest China and the Tibetan Plateau except for permafrost regions, and accounting for about 55% of the land area of China. The southern limit of short-term frozen ground generally swings south and north along the 25° northern latitude line, occurring in the wet and warm subtropic monsoon climatic zone. Its area is less than 20% of the land area of China.     

Studies on frozen ground of China

1ThestatusoffrozengroundinChinaBased on previous studies, Zhou and Guo (1982) summarized the distribution characteristics of permafrost in China and indicated that the permafrost area in China is about 215×104 km2, in which about 163.4×104 km2 is on the Tibetan Plateau. After mapping and zonation of frozen ground in 1983, Xu and Wang suggested that the areas of permafrost, seasonally frozen ground and temporal frozen ground in China were 206.8×104 km2, 513.7×104 km2 and 229.1×104 km2 …     

Organochlorine and mecury concetrations in eggs of grey plovers (Pluvialis squatarola) breeding in the Lena Dlta, north-east Sibveria, 1997

Seven eggs from four clutches of grey plovers ( Pluvialis squatarola ) breeding in the Lena Delta, Sakha Republic, Yakutia, in 1997 were analysed for persistent organochlorines and mercury. Contamination levels were low and within the same range as found in eggs from waders (Charadriiformes) breeding in north-west Europe. One exception was ∑HCH, averaging 99.2 ng g⁻¹ fresh egg mass, a level about ten times higher than in wader eggs from north-west Europe. β-HCH accounted for 98% of the total HCH concentration. There are indications that the pesticide levels may reflect former local use. ∑PCB level (57.0 ng g⁻¹, 62 congeners) and mercury concentration (68.7 ng g⁻¹) can be considered low.     

广州金沙洲广州大学附属实验学校地面沉降形成机理研究

依据地下水动态监测、地面沉降监测和地质钻探的成果,综合研究广州市金沙洲广州大学附属实验学校地面沉降地带的地质构造、人类工程活动特征、岩土体类型、第四系厚度、地层与岩石等因素对地面沉降的影响,分析研究区内地面沉降的动态演变特征。结果表明:脆弱的地质环境条件是广州大学附属实验学校地面沉降形成的内在因素,开挖基坑、桩基础施工及抽排地下水是地面沉降形成的外在因素。在此基础上,得出学校地面沉降是因软土层在抽排地下水及地面附加荷载的共同作用下产生排水固结的结果。     

汶川地震诱发的地面塌陷成因

针对目前由汶川地震诱发的地面塌陷研究尚少的现状,以北川县安昌镇开茂村水没河流域地面塌陷坑群为研究对象,根据所处的地质环境条件,通过现场调查、工程勘察及钻孔岩土试验,探讨了地震诱发的地面塌陷成因及机制。认为塌陷区第四系松散层上部含细颗粒的饱和粉土、粉质粘土和下部粗颗粒的饱和砂层、砂砾层等的存在是产生地面塌陷的前提,强烈的地震诱发了砂土液化是产生地面塌陷的内因,而塌陷坑的陆续出现说明了地面塌陷一般都有个时间发展过程,是一种渐进性质的破坏;且地下水动力条件的改变、真空吸蚀作用、余震作用以及强降雨加剧了潜蚀作用,最终导致地面塌陷的产生与发展。结果表明:这些塌陷坑群的出现主要是由地震砂土液化和潜蚀作用共同作用的结果。