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1.
Kazakhstan regions is seasonal climatic with transient freezing of soil groundduring the winter. Roadbed integrity is important to resist the sustained load transmitted by traffic on the road surface. Freezing of soil ground could significantlyinfluence roadbed integrity in the seasonal freezing climate of Kazakhstan. The proper determination magnitude of frost heave and heaving pressure by the influence of freezing temperatures during the winter season are necessary for design and construction of highways. Thus, experimental tests were conducted on specimens obtained from Astana (Kazakhstan) to determine the freezing pressure and magnitude of frost heaving. 相似文献
2.
Frost heaving is a well-known phenomenon in cold regions, which may occur in wet clayey grounds during winter. Railway track upheaval occurring in cold regions during the winter is generally understood as frost heaving in the subgrade layer. However, it has been confirmed that upheaval due to frost heaving sometimes occurs in the ballast layer. This understanding has been observed in active railways in northern Japan. The samples collected from ballast and subgrade layers have been examined for frost heave susceptibilities and confirmed that ballast layers which contain fines may heave. 相似文献
3.
古尔班通古特沙漠砂的物理力学性质 总被引：7，自引：2，他引：5
野外勘察和大量物理力学性质试验结果表明,古尔班通古特沙漠砂的厚度一般小于200m。粒径较均匀,控制粒径(d60)变化范围在0.12~0.25之间,由北至南,从上到下砂粒直径略有减小。在天然状态下,沙漠砂含水量1%~2%,干密度1.55~1.62g·cm-3,中密状态,低压缩性,渗透系数2.0×10-2~4.0×10-3cm·s-1,临界破坏比降0.9~1.7,破坏形式为流土。抗剪强度指标c=5.0~14.0kPa,φ=29°~34°。承载力特征值100kPa。天然状态的沙漠砂按冻胀率划分为不冻胀性砂,当含水量小于18%时,为不冻胀或弱冻胀性砂。当砂在饱和状态时为冻胀性砂。沙漠砂力学性质的变化主要受干密度和含水量的影响。干密度越大,含水量越小,其力学性质越好。对于沙漠工程,提高沙漠砂的干密度,做好构筑物的防渗排水,避免地基含水量增高,是保证工程设施安全、正常运行的关键。 相似文献
4.
Based on the similarity theory, taking the horseshoe, city-gate and round linings as examples, the value and distribution regularities of normal frost heaving pressures （hereinafter as frost heaving pressures） in tunnels excavated in fractured rock mass in cold regions under different constraints and freezing depths were studied by a test model. It was found that the larger the frozen depth, the larger the frost heaving pressure, and the stronger the top constraint, the larger the frost heaving pressure. For the horseshoe lining and city-gate lining, the top constraint has a greater effect on the frost heaving pressures on the arch and the inverted arch. For the round lining, the influences of the top constraint on the frost heaving pressure in all linings are almost the same. The frost heaving pressure is maximum on the city-gate lining and minimal on the round lining. The largest frost heaving pressure all occur near the foot of the inverted arch for the three kinds of lining. Thus, the test data basically coincide with the observed in situ data. 相似文献
5.
This paper aims to determine the optimal fines content of coarse-grained soil required to simultaneously achieve weaker frost susceptibility and better bearing capacity. We studied the frost susceptibility and strength properties of coarse-grained soil by means of frost heaving tests and static triaxial tests, and the results are as follows:(1) the freezing temperature of coarse-grained soil decreased gradually and then leveled off with incremental increases in the percent content of fines; (2) the fines content proved to be an important factor influencing the frost heave susceptibility and strength properties of coarse-grained soil. With incremental increases in the percent content of fines, the frost heave ratio increased gradually and the cohesion function of fines effectively enhanced the shear strength of coarse-grained soil before freeze-thaw, but the frost susceptibility of fines weakened the shear strength of coarse-grained soil after freeze-thaw; (3) with increasing numbers of freeze-thaw cycles,the shear strength of coarse-grained soil decreased and then stabilized after the ninth freeze-thaw cycle, and therefore the mechanical indexes of the ninth freeze-thaw cycle are recommended for the engineering design values; and (4) considering frost susceptibility and strength properties as a whole, the optimal fines content of 5% is recommended for railway subgrade coarse-grained soil fillings in frozen regions. 相似文献
6.
P.D. Sumner 《Geografiska Annaler: Series A, Physical Geography》2004,86(3):289-302
Conflicting reports appear in the literature from geomorphic studies describing the colder Late Pleistocene environmental conditions of the Lesotho Highlands in southern Africa. Evidence is given for limited glaciation and/or periglacial conditions, with or without permafrost. An investigation of the distribution, morphometric attributes and surface weathering characteristics of relict openwork block accumulations in the area around Thabana‐Ntlenyana, the highest summit in the range, supports the contention for a relatively arid periglacial environment during the Last Glacial period. A phase of enhanced block production is evident from the concentration of blocks in the upper layer of colluvium. Slope mobility on south‐facing slopes is shown in the blockfield fabrics and the increase in downslope relative age of block surfaces. Block production and slope creep are attributed to depressed temperature conditions and seasonal freeze. Colluvium, within which blocks have been incorporated and superimposed, indicates that slope mantles predate the onset of the colder period and evidence militates against either deep snow cover or localised glaciation of south‐facing slopes. 相似文献
7.
A new experiment method is introduced to study the relations between frost heaving strain and stress of soil or fracture rock under different moisture contents, temperatures and stress states. Based on experiments, a new triaxial frost heaving stress-strain relation is presented aiming at tunnel in cold regions. The experimental equipments are strain-controlled and low temperature buildup, and different restrained conditions are controlled by changing the stiffness of a test-force-ring. Then the frost heaving strain and stress of soil or fracture rock can be obtained under different restrained conditions, and the frost heaving stress-strain relation can be got by regression analysis of some feature points. Experiments of saturated sandy soil conducted by this method show that the triaxial frost heaving stress-strain relation could be expressed by logarithmic curves, and the frost heaving stress changes linearly with the logarithm of the frost heaving strain. The stronger the constraint, the smaller the frost heaving strain and the larger the frost heaving stresses. The frost heaving stresses would tend to a limit value with increasing the constraint intensity. The larger the confining pressure, the larger the frost heaving strain and stress. 相似文献
8.
Fine round gravel soil is widely employed in the subgrade of high speed railways in cold regions to prevent frost heaving
and thawing. The lower the fines content in fine round gravel soil, the smaller the quantities of frost heaving and thawing,
but compaction difficulty increases. This study is to obtain the optimum fines content and limited frost heaving and
thawing. The fine round gravel soil filling (FRGSF) used in the Harbin-Qiqihaer Passenger Dedicated Line is taken as the
study object. Influence of fines content on optimum water content, maximum dry density and frost heaving properties of
FRGSF were studied by means of compaction and frost heaving tests. Results show that the maximum dry density of the
FRGSF increases first and then decreases with an increase of fines content, namely there is an optimum fines content for
easy compaction. The method of surface-vibratory instrument is fit for coarse-grained soils, and wet state of
coarse-grained soil is in favor of compaction. Considering the relationship of fines content with maximum dry density and
the frost heaving ratio of FRGSF, the fines content should be limited to within the range of 9%-10%, so that the frost
heaving ratio is less than 1%, and the FRGSF is easily compacted. Water supply is proved to be an important factor influencing
the amount of frost heaving of FRGSF. We also conclude that in the field, it is imperative to control waterproofing
and drainage measures. 相似文献
9.
Soil profiles, colluvial stratigraphy, and detailed hillslope morphology are key elements used for geomorphic interpretations of the form and long-term evolution of triangular facets on a 1200 m high, tectonically active mountain front. The facets are developed on Precambrian gneisses and Tertiary volcanic and plutonic rocks along a complexly segmented, active normal-fault zone in the Rio Grande rift of northern New Mexico. The detailed morphologies of 20− to 350 m high facets are defined by statistical and time-series analyses of 40 field transects that were keyed to observations of colluvium, bedrock, microtopography, and vegetation. The undissected parts of most facets are transport-limited hillslopes mantled with varying thicknesses (0.1 to > 1 m thick) of sand and gravel colluvium between generally sparse (≤10–30%) bedrock outcrops. Facet soils range from (a) thin (≤ 0.2 m) weakly developed soils with cumulic silty A or transitional A/B epipedons above Cox horizons in bedrock or colluvium, to (b) deep (≥0.5–1 m) moderately to strongly developed profiles containing thick cambic (Bw) and/or argillic (Bt) horizons that commonly extend into highly weathered saprolitic bedrock. The presence of strongly weathered profiles and thick colluvium suggests that rates of colluvial transport and hillslope erosion are less than or equal to rates of soil development over at least a large part of the Holocene.The catenary variation of soils and colluvium on selected facet transects indicate that the degree of soil development generally increases and the thickness of colluvium decreases upslope on most facets. This overall pattern is commonly disrupted on large facet hillslopes by irregular secondary soil variations linked to intermediate-scale (20–60 + m long) concave slope elements. These features are interpreted to reflect discontinuous transport and erosion of colluvium down-slope below bedrock outcrops. The degree of weathering in subsurface bedrock commonly increases more systematically upslope on most facets than colluvial soils. This pattern is consistent with an increase in age with height on these fault-generated facet hillslopes.The characteristic range of internal variation in soils and colluvial deposits on a given facet also varies greatly among facets with differing overall morphologies and external environments. Deep cumulic soils and thick colluvium occur consistently on steep (≥ 30°), high, and relatively undissected facets above the narrow central sections of fault segments. Much thinner and less weathered colluvium and soils overlie saprolitic bedrock at shallow depths on low, highly dissected, gently sloping (≤ 20°) facets above complex fault segment boundaries. Parametric and nonparametric analyses of variance indicate that these large-scale contrasts in facet morphology correlate primarily with a few facet subgroups related, in decreasing importance, to variations in range-front faulting, bedrock lithology, and piedmont dissection or aggradation. These factors are related to facet morphology, drainage evolution, and hillslope-soil stratigraphy in a general geomorphic model for fault-generated facets. In this model, segmentation-related changes in the geometry and/or rates of faulting most strongly affect facet size, slope gradient, the thickness of colluvium and soil development, and drainage patterns. Facets of varying heights have similar hillslope forms at the same position on the range front; these characteristic morphologies are established under prevailing tectonic and nontectonic conditions on facets as bedrock is initially exposed from beneath alluvial-covered fault scarps above a height threshold of 15–35 m. 相似文献
10.
Frost susceptibility should be considered in the design and construction of foundations and retaining-wall structures in regions with the seasonally freezing-soil ground condition. When planning construction that goes deep into this soil, one has to understand the impact of horizontal forces to an underground wall and realize the potential effect of frost heaving upon, deep foundations. This article presents a few soil tests for frost heaving and the results of those tests show dangerous data for retaining structures under the soil conditions in Kazakhstan. The main parameters of the soil include frost penetration and heaving rate and amount. So, in designing underground structures, one must understand and consider that frost heaving occurs in various directions; this factor is very important for predicting on the restriction of deformations of structures in the seasonally freezing-soil ground condition. 相似文献
11.
JAMES BOCKHEIM 《Geografiska Annaler: Series A, Physical Geography》2007,89(3):153-165
Soil‐forming processes and soil development rates are compared and contrasted on glacial deposits in two adjacent and coeval valleys of the Quartermain Mountains, which are important because they display Miocene glacial Stratigraphy and some of the oldest landforms in the McMurdo Dry Valleys. More than 100 soil profiles were examined on seven drift sheets ranging from 115 000 to greater than 11.3 million years in age in Beacon Valley and Arena Valley. Although the two valleys contain drifts of similar age, they differ markedly in ice content of the substrate. Whereas Arena Valley generally has ‘dry‐frozen’ permafrost in the upper 1 m and minimal patterned ground, Beacon Valley contains massive ice buried by glacial drift and ice cored rock glaciers and has ice‐cemented perma‐frost in the upper 1 m and considerable associated patterned ground. Arena Valley soils have twice the rate of profile salt accumulation than Beacon Valley soils, because of lower available soil water and minimal cryoturbation. The following soil properties increase with age in both valleys: weathering stage, morphogenetic salt stage, thickness of the salt pan, the quantity of profile salts, electrical conductivity of the horizon of maximum salt enrichment, and depth of staining. Whereas soils less than 200 000 years and older soils derived from sandstone‐rich ground moraine are Typic Anhyorthels and Anhyturbels, soils of early Quaternary and older age, particularly on dolerite‐rich drifts, are Petronitric Anhyorthels. Arena Valley has the highest pedodiversity recorded in the McMurdo Dry Valleys. The soils of the Quartermain Mountains are the only soils in the McMurdo Dry Valleys known to contain abundant nitrates. 相似文献
12.
《Geomorphology》1988,1(2):143-160
A soil chronosequence was examined on landslide scars of different ages in the Taranaki hill country. This area, underlain by Tertiary silty sandstone, was deforested 90 years ago. Sequential aerial photographs, historical terrestrial photographs and documented erosion events were used to date landslide scars formed since forest removal and establish age control for the chronosequence.Soil depth increased with landslide age and was used as an index of soil formation. Mean soil depth increased from 5 cm on 15 year old scars to 20 cm on 82 year old scars. Measures soil depths were attributed to rafted soil, colluvium and bedrock weathering. A chronofunction was derived by regressing mean soil depth against the logarithm of known scar age. Similarly, a second chronofunction was derived by excluding depths of rafted soil from the calculation of mean soil depth to describe soil accumulation on exposed bedrock within the landslide scar. This chronofunction showed a better correlation (r2 = 0.92 compared with r2 = 0.79) and can give an estimate of the age of other landslide scars to within ±27% for ages up to 90 years.The rate of soil depth increase averaged 3.5 mm yr−1 over the first 40 years after slipping but dropped to 1.2 mm yr−1 over the following 50 years. The logarithmic chronofunction suggests that the rate of soil formation further decreases beyond 90 years. Soil formation is primarily a result of bedrock weathering and accumulation of colluvium derived from surface fragmentation of exposed bedrock and crumbling scar margins. 相似文献
13.
Wedge-like structures filled with silty sand penetrate Quaternary fluvial and aeolian sediments and, in places, Tertiary bedrock on the Ordos Plateau, North China. The wedges reflect thermal contraction cracking of either permafrost or seasonal frost during the Late Pleistocene and early Holocene. Wedges of about 1 m in depth form polygonal nets of 2-3 m in diameter(type B). They contrast with wedges of 3-4 m in depth that form polygons of 10-15 m in diameter(type A).This review focuses upon the highly variable size of the inferred polygon nets and discusses the problem of differentiating between seasonally and perennially frozen ground, or between seasonal frost and permafrost. 相似文献
14.
In the cold regions of northern China, incidents of municipal underground gas pipeline rupture and leakage occur quite frequently,
most often in winter. To prevent harm to citizen safety and property, analysis of the causes of such cracking and leakage is therefore
valuable. Two incident analyses are discussed here and the reasons why most of these types of cases occur during winter are clarified.
The effects of vehicle loadings above buried pipelines are calculated and compared with the effects and calculations of frost heaving
forces. We demonstrate that when the soil layer above a pipeline freezes rapidly, the soil generates repeated frost heaving, which exerts
heaving forces on the pipeline that can result in fatigue crack propagation and ultimate pipeline failure. Therefore, the incident induced
by frost heaving is one of the primary reasons of gas pipeline failure. Based on these analyses, we present some recommendations
pertaining to the proper design, construction, and management of gas pipelines. 相似文献
15.
Maria Sarady Eva A.U. Sahlin 《Norsk geografisk tidsskrift. Norwegian journal of geography》2016,70(2):82-94
The impact of snow cover on seasonal ground frost and freeze-thaw processes is not yet fully understood. The authors therefore examined how snow cover affects seasonal ground frost in a coastal setting in northern Sweden. Air and soil temperatures were recorded in a paired-plot experiment, both with and without snow cover, during the frost season 2012–2013. The frequency, duration, and intensity of the freeze-thaw cycles during the frost season were calculated. The results showed that the freeze-thaw frequency was 57% higher at the soil surface and the intensity 10 °C colder in the spring of 2013, when the ground lacked snow cover. Furthermore, the duration of the seasonal freeze-thaw cycle was 30 days longer on average in cases where there was natural snow accumulation. The correlation between air and ground surface temperatures weakened with increased snow-cover depth. The authors conclude that continued increases in air temperature and decreases in snow in coastal northern Sweden might alter freeze-thaw cycles and thus affect natural and human systems such as geomorphology, ecology, spatial planning, transport, and forestry. 相似文献
16.
Satoshi Akagawa 《寒旱区科学》2021,13(2):77-86
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. 相似文献
17.
Frozen ground is significantly stiffer than unfrozen ground. For bridges supported on deep foundations, bridge stiffness is also
measurably higher in winter months. Significant changes due to seasonal freezing in bridge pier boundary conditions require additional
detailing in order to ensure a ductile performance of the bridge during a design earthquake event. This paper reports the latest
results obtained from a project that systematically investigated the effects of seasonally frozen soil on the seismic behavior of
highway bridges in cold regions. A bridge was chosen and was monitored to study its seismic performance and assess the impact
of seasonally frozen soil on its dynamic properties. A Finite Element (FE) model was created for this bridge to analyze the impact
of seasonal frost. It was found that when frost depth reaches 1.2 m, the first transverse modal frequency increases about 200%
when compared with the no-frost case. The results show that seasonal frost has a significant impact on the overall dynamic behavior
of bridges supported by pile foundations in cold regions, and that these effects should be accounted for in seismic design. 相似文献
18.
Western Jilin Province is a typical seasonal frost region, and is also one of the severest salinization areas of China. In this study, we aim to examine the saline soil in Da'an and Wukesong areas, western Jilin Province, and mainly analyze the granulometric composition and distribution of salt in soil profiles. Four sampling sites, two in Da'an and two in Wukesong respectively, are chosen for study. The granulometric composition, especially silt and clay content change in different sites and soil depths are analyzed. Analysis of total and components of soluble salt shows that the surface soil is weak carbonate saline, in which the main cation is Na+ and the main anion is HCO3-. The total amount of soluble salt presents a decreasing tendency with increasing depth. The comprehensive analysis of granulometric composition and soluble salt shows that the clay content and soluble salt content present similar variation tendency with an increase of depth. 相似文献
19.
Characteristics of the mineral phase constituents of lacustrine deposits from the Fildes Peninsula of King George Island, Antarctica and their environmental implication 总被引：1，自引：0，他引：1 
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20.
WERNER NEL JAN C. BOELHOUWERS MPHUMZI B. ZILINDILE 《Geografiska Annaler: Series A, Physical Geography》2009,91(4):313-319
Marion Island in the South Indian Ocean has a maritime climate dominated by diurnal frost processes in the landscape. We test the hypothesis that synoptic time‐scale measurements are essential in understanding the drivers of diurnal frost processes. Preliminary results from automated microclimate measurements in a polar desert habitat show that diurnal soil surface temperatures on Marion Island are influenced by a complex interaction of radiation balance, air mass circulation, cloud cover and snow. The passage of synoptic scale weather systems influences soil thermal characteristics through changes in dominance of the radiation budget. Soil frost on Marion appears to be dependent on clear skies, while synoptic weather systems affect the duration and intensity of soil frost processes and non‐radiative heat fluxes. Air circulation patterns at Marion Island influence diurnal scale temperature fluctuations and its direct and indirect interactions with ecosystem processes. The data suggest that in a maritime sub‐Antarctic environment the climatic drivers of soil frost occur at a finertemporal resolution than for seasonal and permafrost environments and needs to be measured at a diurnal time‐scale to be meaningful. 相似文献