共查询到20条相似文献，搜索用时 62 毫秒
1.
Brainerd Mears 《Quaternary Research》1981,15(2):171-198
Nonsorted polygons in the uppermost 2 to 3 m beneath Pleistocene surfaces indicate permafrost at 1340 m and higher elevations in the intermontane and piedmont plains of Wyoming during the Wisconsin, and perhaps earlier, glacial maxima. The polygons, as much as 10 m in diameter, are delineated by wedges that vary in depths, range from narrow to moderately flared forms, and deform host materials. The wedges have silty fine-to-medium sand matrices (largely eolian) with pebbles or clasts from hosts of gravel or bedrock. Some wedges may reflect seasonal cracking in a periglacial active zone, but most are either permafrost sand-wedge relics or, less commonly, ice-wedge casts. Alternative explanations are rejected largely because similar features are apparently lacking in the lower and warmer plains from eastern Colorado southward. The wedges suggest an arid, windy, periglacial environment whose mean-annual temperatures are conservatively estimated as some 10° to 13°C colder than those at present. Although late Wisconsin-early Holocene floral and faunal evidence indicates lowered montane biotic zones, the eolian and periglacial features indicate a lack of extensive forest cover on the basin floors. In conjunction with vertebrate-fossil associations of grazing and tundra animals, the wedges may provide a parallel line of evidence for a former periglacial steppe, or “steppe-tundra”, in the Wyoming basins. 相似文献
2.
Robert F. Black 《Quaternary Research》1976,6(1):3-26
Ice wedges are wedge-shaped masses of ice, oriented vertically with their apices downward, a few millimeters to many meters wide at the top, and generally less than 10 m vertically. Ice wedges grow in and are confined to humid permafrost regions. Snow, hoar frost, or freezing water partly fill winter contraction cracks outlining polygons, commonly 5–20 m in diameter, on the surface of the ground. Moisture comes from the atmosphere. Increments of ice, generally 0.1–2.0 mm, are added annually to wedges which squeeze enclosing permafrost aside and to the surface to produce striking surface patterns. Soil wedges are not confined to permafrost. One type, sand wedges, now grows in arid permafrost regions. Sand wedges are similar in dimensions, patterns, and growth rates to ice wedges. Drifting sand enters winter contraction cracks instead of ice. Fossil ice and sand wedges are the most diagnostic and widespread indicators of former permafrost, but identification is difficult. Any single wedge is untrustworthy. Evidence of fossil ice wedges includes: wedge forms with collapse structures from replacement of ice; polygonal patterns with dimensions comparable to active forms having similar coefficients of thermal expansion; fabrics in the host showing pressure effects; secondary deposits and fabric indicative of a permafrost table; and other evidence of former permafrost. Sand wedges lack open-wedge, collapse structures, but have complex, nearly vertical, crisscrossing narrow dikelets and fabric. Similar soil wedges are produced by wetting and drying, freezing and thawing, solution, faulting, and other mechanisms. Many forms are multigenetic. Many socalled ice-wedge casts are misidentified, and hence, permafrost along the late-Wisconsinan border in the United States was less extensive than has been proposed. 相似文献
3.
4.
成都平原第四纪化石冰楔的发现及古气候意义 总被引：5，自引：0，他引：5
最近,在成都平原西缘,大邑城西氮肥厂附近,斜江河西岸,上新统-下更新统大邑砾岩剖面的北端新开挖的露头上,发现了4条化石冰楔。这里的地理坐标是30°35'N103°31'E,海拔530m.这些冰楔发育于大邑砾岩露头的顶部。其中最大的一条,顶部宽3m,向下延伸2.5m.这些冰楔垂直向下延伸,与大邑砾岩层面斜交。所以,它们是在大邑砾岩沉积之后并经过构造变动后形成的,是大邑砾岩的后生冰楔。化石冰楔的充填物的特征与大邑砾岩有明显差别:前者为棕黄色,后者为灰白-黄色;前者砾径分选较好,砾径较细,一般长5cm~15cm,而后者砾径分选较差,粗大者20cm~30cm;前者的砾石含量高,约95%,后者的砾石含量低,约85%;前者砾石ab面产状无优势方向,而后者的ab面产状显示优势方向,倾向170°~210°,倾角30°~40°.由于两者有上述差别,所以,化石冰楔在露头上可以被识别出来。采用ESR法测定冰楔充填物的时代为0.171Ma.由此看来,这些冰楔的形成时代可能相当于V28-238深海岩心氧同位素曲线第6气候期(0.195Ma~0.128Ma),也可与中国黄土L2~5(0.195Ma~0.180Ma)和L2~4(0.180Ma~0.167Ma)所记录的气候波动和青藏高原倒数第二次冰期对比。一般认为,冰楔是多年冻土的指示器,所以这些化石冰楔反映了成都平原在第四纪曾一度发育多年冻土。据研究,冰楔只能形成于年均温<-6℃的地方,高海拔多年冻土下界大致与-2℃~-4℃年均等温线相符。现今,大邑附近年均温约16℃.那么,化石冰楔形成时期,成都平原年均温至少比现今下降了18℃. 相似文献
5.
6.
土楔和冰楔假形及其古气候意义 总被引：1，自引：0，他引：1
由于土楔及冰楔所处冻土的含冰状况不同,二者对冻土退化的响应不同。土楔的形状及大小乃至其中的充填物可以完整地保存下来,而冰楔在融化过程中经受强烈变形,其原形状很难保存下来,以至无法辨认。已报道的冰楔假形中,有相当部分可能是原生土脉,甚至是活动层土楔。冰楔在多年冻土环境下生长,其假形可以指示古冻土曾存在过。但它与温度之间没有简单的对应关系,因为楔形构造的形成是地-气综合因素相互作用之结果。土楔可以是原生的,也可以是次生的,它与多年冻土环境并无必然联系。 相似文献
7.
青海湖北岸刚察县城东与泉吉乡西发现原生砂楔群, 楔内充填物均为中细粒砂, 楔体底部中细粒砂ESR测年数据表明, 刚察县城东3个原生砂楔发育时代分别为(774±70) ka、(773±70) ka和(229±20) ka, 泉吉乡西1个原生砂楔形成时代为(197±18) ka, 反映该区至少发育两期原生砂楔, 其形成时代分别对应昆仑冰期和倒数第二次冰期. 基于原生砂楔的特殊形成环境, 估算青海湖盆地在昆仑冰期早期的年均温不高于-7.5~-10 ℃, 比现今至少低9.2~11.7 ℃, 中更新世早期青海湖盆地发育多年冻土, 青藏高原东北部可能已经进入冰冻圈; 倒数第二次冰期的年均温不高于-9.5~-10 ℃, 比现今低11 ℃以上. 相似文献
8.
JEF VANDENBERGHE PETER VAN DEN BROEK 《Boreas: An International Journal of Quaternary Research》1982,11(4):299-315
In three excavations in the southern Netherlands and northern Belgium, the Weichselian convolutions in fine sand, silt and clay deposits were investigated, and an attempt was made towards a semi-quantitative approach to some sediment parameters. This, together with a detailed field survey, enabled interpretation of the deformations as forms of periglacial loadcasting. They originated from the time of permafrost degradation when large quantites of water were available. The amplitude of the involutions can be related to the depth of the permafrost table at that time. During the weichselian, two periods occurred in which this involution process could have been active 相似文献
9.
Xiang‐Jun Liu Zhong‐Ping Lai 《Boreas: An International Journal of Quaternary Research》2013,42(2):333-341
Sand wedges and ice‐wedge casts in the Qinghai Lake area on the northeastern Qinghai‐Tibetan Plateau (QTP) occur within alluvial gravel or river terrace deposits. In this study, we report the results of quartz Optically Stimulated Luminescence (OSL) dating of the infill of five relict sand wedges and one ice‐wedge cast. Combining our dating results with previously published luminescence ages of permafrost wedges in the Qinghai Lake area, we show that sand/ice wedges formed at c. 62 ka, c. 45 ka and between 30 and 15 ka, and that the mean annual air temperature (MAAT) was depressed by at least ～3°C relative to present during the sand/ice‐wedge formation periods. This new work is partially corroborated by post‐LGM proxy records from lakes and aeolian deposits reported from the northeastern QTP. It also significantly extends the palaeoenvironmental record in the region in the period before the LGM, when other proxy records are rare, allowing a better understanding of the palaeoenvironmental conditions on the northeastern QTP. 相似文献
10.
《Russian Geology and Geophysics》2015,56(11):1522-1530
Isolated lenses of diamictites laying discordantly over the Late Riphean (Cryogenian) Kirgitei Formation were found in the immediate vicinity of the Vendian Taseeva Group stratotype in the Taseeva River valley and assigned to the Shishina Member a few meters in visible thickness. The Shishina diamictites are, likely, of glacial origin as they (i) lie at the base of the Vendian section, (ii) consist of unsorted dolomitic clasts from fine gravel to more than 0.5 m boulders suspended in a mud matrix, and (iii) show glacial striation on clasts. The glacial origin is further supported by the morphology of stones, which resemble a smoothing iron or a bullet, with a swelly top, a flat bottom, and a steeply cut rear and form clusters produced by disintegration of larger boulders. The stones bear signatures of cleavage, cracks, grooves, and striation on the faces, while the matrix looks undeformed. The Shishina Member has no genetic relation with the underlying Kirgitei Formation but rather correlates sedimentologically with the Ulyakha Member tillites at the base of the Vendian Marnya Formation (Oselok Group) in the Sayan foothills. The Shishina Member stones may derive from the Late Riphean (Cryogenian) Dzhura Formation exposed 4 km downstream of the site along the Taseeva. They occur near the base of the Aleshinsky Formation (lowermost unit of the Taseeva Group) of cross-bedded glaciofluvial sandstone, gravelstone, conglomerate, and sandy gravel mixtite transported from east to west (from the Siberian Craton interior to its margins) and deposited in channel bars or as gravel lags. The lower member of the Aleshinsky Formation comprises two associations of clasts: (i) coarse quartzose sand and gravel and (ii) fine and medium quartz and lithoclastic sand. Rocks in the former are well rounded, with traces of wind erosion, while the latter association is composed of mechanically eroded angular material transported to short distances from a metamorphic and metasedimentary source on the Craton margin. The Aleshinsky clastics have their composition and grain size patterns similar to those of the glaciofluvial Plity, Nersya, and Kedrovy members of the Marnya Formation in the Sayan area. According to sedimentological evidence, the Shishina diamictites are tillites identical to the Ulyakha moraine at the base of the Sayan Oselok Group and may be a missing link in the Taseeva Group stratigraphy. 相似文献
11.
东北某些地区长期存在着一定规模的地下冻土,在地下水源热泵的运行中可视为天然冷源。天然冷源对地下水源热泵的利用产生一定的影响。为了提高地下水源热泵运行效率,运用室内外实验和数值模拟方法探寻冷源对地下水源热泵影响规律。对加格达奇地区的冷源场地进行了室内热物性试验和现场岩土热响应试验。研究表明：该地区砂、砾的热物性参数（比热容、导热系数）随深度增加呈现离散现象,砂岩、花岗岩热物性参数变化不大;岩土体导热系数花岗岩最大,砾、砂最小,砂岩居中;比热容受深度影响波动较大,特别是不同深度的砾、砂层比热容差别较大。依据该场地的地质条件,构建数值模型,开展模拟研究,对多井抽灌系统下热突破现象以及影响范围进行模拟分析,模拟结果显示冷源对该场地地下水源热泵的影响范围在150 m以内,而且在小于75 m的范围内对地下水源热泵的影响最为显著,为未来该地区地下水源热泵的设计、选址提供理论基础和参考依据。 相似文献
12.
山西大同、内蒙古鄂尔多斯冰楔、砂楔群的发现及其环境意义 总被引：7，自引：3，他引：4
研究了山西大同、内蒙古东胜和乌审旗地区发现的大量冰楔假型、砂楔、寒冻裂隙和南部白城子附近的冰卷泥.根据这些冰缘现象,并参考前人工作成果,划定了晚更新世晚期末次冰期时多年冻土的南界,并根据所获得的年代资料划分了4次冰缘期:33ka BP,30～26ka BP,20～16ka BP和8ka BP左右,当时的温度比今天分别降低8.4℃,12～13℃,10℃和7～10℃. 相似文献
13.
基于微观结构的青藏高原风积沙导热系数变化机理研究 总被引：1，自引：0，他引：1
风积沙作为青藏高原一种重要的局地因素, 改变了多年冻土的赋存条件. 风积沙的导热系数特征对预报分析其对冻土赋存有利或者不利具有重要作用. 采用非稳态法对青藏高原红梁河风积沙进行了导热系数测试, 并结合电镜扫描/能谱分析, 从微观结构的角度探讨了风积沙的导热系数变化机理. 结果表明: 研究区风积沙平均粒度为242.427 μm; 标准偏差值为0.125, 分选极好; 偏度为0.359, 接近对称; 峰度值为1.086, 峰态中等; 颗粒粒径主要分布在75～500 μm之间, 沙粒均匀, 不含黏土及砾石成分, 自然堆积状态下其孔隙率为0.391. 天然状态下的风积沙颗粒呈类球形, 颗粒磨圆度高, 点与点接触, 颗粒间孔隙较大; 表面有明显撞击坑和擦痕, 这导致颗粒的比表面积增大, 连通性增强, 孔隙率增加. 干燥状态下风积沙颗粒的相互接触面积较小, 孔隙由空气填充, 导热系数较低; 而在湿润状态下, 正温时孔隙中的水间接增大了风积沙的接触面积, 导致其导热系数增大; 负温时, 孔隙内的水变成冰, 从而导致导热系数进一步增大. 天然状态下, 暖季地表风积沙含水量较低, 导热系数较低, 而冷季地表风积沙含水量较大, 导热系数较大. 此外, 风积沙为颗粒物质, 表面光滑, 颗粒之间粘性小, 孔隙未被填堵, 结构松散, 这些因素导致自然堆积状态下其渗透系数较一般细砂大, 透水性良好, 保水性差, 是防冻胀较好的换填材料. 相似文献
14.
Observed depths to the base of the ice-bearing permafrost (!BPF) as determined from geophysical well-log and survey information in the Mackenzie Delta and offshore Beaufort Sea continental shelf show significant variation. Depths range from over 700m beneath the northeastern portion of Richards Island and the adjacent offshore region to the north, to less than 100m in the modern Mackenzie Delta and offshore Mackenzie Bay regions. Along the Tuktoyaktuk Peninsula, permafrost thicknesses exceed 600m but tend to thin to less than 100m in a southeasterly direction. The wide variation in the thickness and distribution of permafrost is due in part to differences in the subsurface deltaic lithologies and to the complexity of the past surface temperature history, exhibited, for example, by fluctuations of the mean annual ground temperature. Geological cross-sections showing variation in the Tertiary and Upper Cretaceous deltaic sequences indicate a good correlation with the permafrost distribution. In particular, where the sand and gravel units of the Iperk and Kugmallit Sequences predominate, permafrost is thick owing to the high thermal conductivities of the ice-rich sediments. Conversely, where the low thermal conductivity shales and mudstones of the Richards Sequence are present, permafrost is accordingly thinner. Numerical models of permafrost aggradation in the Mackenzie Delta region suggest that Early and Late Wisconsinan surface temperatures were of the order ?18°C. A mid-Wisconsinan rise in temperature to approximately ?8°C, similar to mean surface temperature today, is also indicated. This proposed palaeoclimate is sufficient to account for the observed maximum permafrost thicknesses in the region. 相似文献
15.
何瑞霞 金会军 蒋观利 张泽 陈雪梅 Raul David SERBAN Mihaela SERBAN Jef VANDENBERGHE Valentin V.SPEKTOR Hugh M.FRENCH 《冰川冻土》2021,43(1):263-273
冰缘遗迹（特别是冷生楔形构造及融冻褶皱）是重建古气候及第四纪晚期多年冻土环境的重要证据。内蒙古鄂尔多斯高原是我国北方地区冰缘现象最为发育的地区之一。为准确了解鄂尔多斯高原冰缘遗迹类型及其分布特征、区域冻土演化历史等,中国科学院西北生态环境资源研究院和荷兰自由大学共同组成科研小组,于2018年5—6月组织了“鄂尔多斯高原冰缘遗迹科学考察”。考察区域涉及靖边—城川—乌审旗—鄂尔多斯东胜区一带约12 000 km2的范围。考察内容主要包括鄂尔多斯高原冰缘遗迹类型及特征、分布区域、各类型冰缘遗迹所指示的气候条件的初步推断等。结果表明：冻融褶皱和冷生楔体构造是鄂尔多斯高原主要存在的两大类冰缘遗迹。基于本次考察中关于冰缘遗迹的分布与特征等新发现,并综合前人研究成果,初步推断：在气温极低、多年冻土非常发育的时段,有利于形成各类冷生楔状构造,如冰楔假形和大型原生砂楔等;在气候转暖、多年冻土退化,但还没有全部融化完阶段,可能形成融冻褶皱;区域性大面积分布和成群出现的融冻褶皱一般反映较暖气候环境下,多年冻土层上部已退化到一定程度。基于光释光（OSL）年代测试结果,结合冰缘遗迹的特征及其所指示的古气候环境,初步重建了鄂尔多斯5万年以来的冻土环境变化序列。区内多年冻土在多年冻土最大期（LPM,25~19 ka BP）时最发育,以大面积连续多年冻土为主;之后,随气温转暖,总趋势呈退化状态,多年冻土分布逐渐变为片状→岛状→零星斑状,直至现今全部融完变为深季节冻土区。 相似文献
16.
Organic sediments in a gravel quarry at Block Fen, Cambridgeshire, form a sheet dividing lower from upper gravels. Analyses of pollen, macroscopic plant remains and molluscs from these organic sediments are presented. They indicate the presence of temperate freshwater and slightly brackish fine floodplain sediments, which, on the basis of the palaeobotany, are correlated with the temperate Ipswichian Stage. The freshwater sediments, ascribed to Ipswichian substage IIb, occur at ca. ?3 m OD. Marine-influenced tidal sediments, ascribed to Ipswichian substage III, occur at ca. ?6 m OD. No evidence was found for the presence of more than one temperate stage in the sequence. The lower gravels are then correlated with the cold Wolstonian Stage and the upper gravels with the cold Devensian Stage. In contrast to the woodland environments indicated by the palaeobotany of the Ipswichian organic sediments, post-Ipswichian pollen diagrams and macroscopic plant remains in the upper suite of sands and gravels indicate open tree-less vegetation typical of the cold Devensian Stage. They also contain a typical cold-stage mollusc fauna. The sediments containing these floras and faunas are associated with thermal contraction cracks, indicating the presence of permafrost. The final sand and gravel aggradation in the Devensian forms the Block Fen Terrace, near 0 m OD. The evidence indicates that it is younger than the lacustrine sediments resulting from the blocking of the Fenland at the Wash by Late Devensian ice at ca. 18.5 ka BP. The sequence at Block Fen is related to nearby Ipswichian and Devensian sediments at Chatteris, March, Wimblington and Mepal, and to deposits at Wretton on the east margin of Fenland. The correlation permits an outline reconstruction of the history of the valley carrying the River Great Ouse between the Isle of Ely and the Chatteris and March ‘islands’ from the time of a gravel aggradation before the Ipswichian to the Flandrian. The reconstruction shows the time and level of the Ipswichian marine incursion into the Middle Level of Fenland and the extent of aggradation and erosion in the Devensian. 相似文献
17.
MATTI SEPPALA JAMES GRAY JEAN RICARD 《Boreas: An International Journal of Quaternary Research》1991,20(3):259-285
Morphological and vegetation mapping and stratigraphic studies were carried out on a 60 by 250 m low–centered polygon field on a flood–plain of the Riviére Deception in the continuous permafrost zone of northernmost Ungava. Analyses of grain size, water and ice content, deformation structures, and macrorests were carried out on drill–core samples, up to a maximum depth of 3.19 m, and radiocarbon dates were obtained from several peat horizons. Five different vegetational habits were identified: uplifted banks, ice–wedge fissures, hummocky centres, wet polygon centres, and water ponds. The stratigraphic analyses revealed many sand layers and organic layers, alternating with a few layers of segregated ice. In the raises banks, brown fen peats represent former wet conditions prior to bank uplift. Total ice volumes of the core samples from polygon centres and banks averaged 60%, and were generally in the form of pore ice. Segregated ice was concentrated in ice wedges. The Low gradient of the polygon field and the shallow active layer are responsible for impded drainage. The origins of this isolated low–centred polygon field are discussed in terms of special local terrain conditions. River flooding since glacio–isostatic emergence at 6000 BP repeatedly spread alluvial sands onto the low flood–plain, which thus became progressively built up to its present elevation. Peat layers buried by these alluvial sands have permitted the changing local drainage conditions to be radiocarbon–dated for the last 2600 years for the core sites. Impeded drainage, low winter temperatures, probable thin snow cover, rapid sedimentation of flood–plain sands, and high volumetric ice contents have created the critical thermal regime necessary for repeated frost cracking in a polygonal pattern, with concomitant ice–wedge dev–elopment. Ice wedges developed at least as early as 2200 BP, causing the formation of low banks. Further growth of ice wedges deformed the peat and sand layers on the bank margins and led to the rise of the latter to heights of 0.5 to 1 m above the intervening low wet polygon centres. More water was then collected in the depressions, leading to a transformations of the vegetation cover from mossy heath to sphagnum bog, wet fen, sedge-covered ponds, and eventually in some cases to open-water pools. The stratigraphic evidence suggests that several generations of high banks formed and disappeared and that their position has changed. Deformation by continued ice–wedge growth has been insignificant since 1000 BP, However. A relatively thick surface peat layer also indicates that sand layers have not been contributed to the polygon field by flooding since ? 500 BP. 相似文献
18.
Jef Vandenberghe Hugh M. French Aldar Gorbunov Sergei Marchenko Andrey A. Velichko Huijun Jin Zhijiu Cui Tingjun Zhang Xudong Wan 《Boreas: An International Journal of Quaternary Research》2014,43(3):652-666
This paper accompanies a map that shows the extent of permafrost in the Northern Hemisphere between 25 and 17 thousand years ago. The map is based upon existing archival data, common throughout the Northern Hemisphere, that include ice‐wedge pseudomorphs, sand wedges and large cryoturbations. Where possible, a distinction is made between areas with continuous permafrost and areas where permafrost is either spatially discontinuous or sporadic. The associated mean annual palaeo‐temperatures that are inferred on the basis of present‐day analogues increase understanding of the possible changes in permafrost extent that might accompany current global warming trends. Areas with relict permafrost and areas that were formerly exposed due to lower sea level (submarine permafrost) are also mapped. Mapping is mostly limited to lowland regions (areas approximately <1000 m a.s.l.). Striking features that appear from the map are (i) the narrow permafrost zone in North America, which contrasts with the broader LPM permafrost zone in Eurasia (that may be related to different snow thickness or vegetation cover), (ii) the zonal extent of former LPM permafrost (that may reflect sea‐ice distribution), which contrasts with the present‐day pattern of permafrost extent (especially in Eurasia) and (iii) the relatively narrow zones of LPM discontinuous permafrost (that may indicate strong temperature gradients). 相似文献
19.
Szabolcs Ákos Fábián János Kovács Gábor Varga György Sipos Zoltán Horváth Edit Thamó‐Bozsó Gábor Tóth 《Boreas: An International Journal of Quaternary Research》2014,43(3):722-732
Wedge structures and involutions suggest that Late Pleistocene frozen ground, either permafrost or deep seasonal frost, extended at least as far south as latitude 47°N in central Europe (the Pannonian Basin). Optically stimulated luminescence dating of the sand infill from a number of wedges indicates that emplacement of the sand infill occurred during the Late Pleistocene (22.2–15.7 ka). This suggests that during this time the mean annual air temperature was depressed by at least ～15°C relative to the present. Either continuous or discontinuous permafrost was probably present in the north and NW of the Pannonian Basin. The subsequent thaw of frozen ground is indicated by the widespread occurrence of deformed sediments. The presence of soil (ground) wedges suggests conditions of deep seasonal frost probably existed during the period when climate ameliorated following the Last Permafrost Maximum (LPM). 相似文献
20.
青藏高原脆弱的生态系统以及人类工程活动,加剧了青藏工程走廊线性工程两侧沙漠化、荒漠化发展趋势,尤其冻土块石路基面临日益严重的风积沙灾害问题。以多年冻土区高等级公路块石路基为研究对象,采用数值模拟分析风积沙环境下封闭块石路基的降温性能和长期热稳定性。结果表明：风积沙堆积对封闭块石路基下部土层冻土温度的影响程度高于冻土上限,1.0 m湿沙工况降低冻土温度,0.2 m干沙则增大冻土温度。升温背景下,随年平均气温增加风沙堆积对路基冻土上限影响程度增强,干沙增大冻土融化深度,湿沙抬升冻土上限。随冻土含冰量减小,路基中心冻土上限对气候升温敏感性增加,风沙堆积影响减弱。气候升温和风沙堆积条件下,在年平均气温低于-5.5℃时,宽幅沥青路面封闭块石路基能够满足降温要求,使人为冻土上限保持在块石层内。研究成果可为风沙危害区多年冻土块石路基的病害治理和拟建青藏高速公路块石路基设计提供科学依据。 相似文献