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1.
The Qinghai–Tibet Plateau is the largest permafrost region at low latitude in the world. Climate warming may lead to permafrost
temperature rise, ground ice thawing and permafrost degradation, thus inducing thermal hazards. In this paper, the ARCGIS
method is used to calculate the changes of ground ice content and active layer thickness under different climate scenarios
on the Qinghai–Tibet Plateau, in the coming decades, thus providing the basis for hazards zonation. The method proposed by
Nelson in 2002 was used for hazards zonation after revision, which was based on the changes of active layer thickness and
ground ice content. The study shows that permafrost exhibits different degrees of degradation in the different climate scenarios.
The thawing of ground ice and the change from low-temperature to high-temperature permafrost were the main permafrost degradation
modes. This process, accompanied with thinning permafrost, increases the active layer thickness and the northward movement
of the permafrost southern boundary. By 2099, the permafrost area decreases by 46.2, 16.01 and 8.5% under scenarios A2, A1B
and B1, respectively. The greatest danger zones are located mainly to the south of the West Kunlun Mountains, the middle of
the Qingnan Valley, the southern piedmont of the Gangdise and Nyainqentanglha Mountains and some regions in the southern piedmont
of the Himalayas. The Qinghai–Tibet Plateau permafrost region is in the low-risk category. Climate warming exacerbates the
development of thermal hazards. In 2099, the permafrost region is mainly in the middle-risk category, and only a small portion
is in the low-risk category. 相似文献
2.
青藏铁路北麓河试验段冻土工程地质特征及评价 总被引：43，自引：16，他引：27
冻土问题是青藏铁路建设的难题之一,为良好的解决这一问题,详细了解线路通过地区的冻土工程地质特征并对其做出工程地质评价至关重要.在目前完成的青藏铁路北麓河试验段的冻土勘察工作表明,该试验段的土层以富含厚层地下冰的细粒土为主,试验段地下水丰富,全段高温与低温多年冻土都有分布,冻土上限深度一般为2～3m.综合上述特征,该试验段综合评价为不良和极差冻土工程地质地段.在类似地区进行铁路建设,工程措施设计和采用中要充分考虑冻土工程地质特征,否则可能导致工程建设的隐患甚至所采取工程措施的失败. 相似文献
3.
4.
青藏高原开发中的冻土问题 总被引：46，自引：0，他引：46
在国家决策西部大开发战略之际, 正确评价青藏高原开发中所面临的冻土问题, 为生态环境建设和国民经济持续稳定发展提供依据, 显得更为重要。多年冻土占据着青藏高原一半以上的疆土面积, 受全球气候变化和人为活动的共同影响, 在过去的几十年中已发生了不同程度的变化, 且随着人类活动增强, 变化必将加剧, 冻土问题也将显得日益突出。多年冻土的变化主要表现为多年冻土的地温升高、上限下降和面积缩减等, 进而影响到各类工程的地基稳定性, 使工程建筑受到不同程度的破坏;同时, 由于气候变化、过度放牧和工程活动的影响, 地面水热状况改变, 尤其是地表土壤层中水分含量的降低, 导致了草场退化, 生态环境恶化。在分析这些冻土问题原因的基础上, 作者预测了在未来开发中可能出现的冻土问题, 并提出了建议。 相似文献
5.
Active layer thickness variations on the Qinghai–Tibet Plateau under the scenarios of climate change
Climate change has greatly influenced the permafrost regions on the Qinghai–Tibet Plateau (QTP). Most general circulation
models (GCMs) project that global warming will continue and the amplitude will amplify during the twenty-first century. Climate
change has caused extensive degradation of permafrost, including thickening of the active layer, rising of ground temperature,
melting of ground ice, expansion of taliks, and disappearance of sporadic permafrost. The changes in the active layer thickness
(ALT) greatly impact the energy balance of the land surface, hydrological cycle, ecosystems and engineering infrastructures
in the cold regions. ALT is affected by climatic, geographic and geological factors. A model based on Kudryavtsev’s formulas
is used to study the potential changes of ALT in the permafrost regions on the QTP. Maps of ALT for the year 2049 and 2099
on the QTP are projected under GCM scenarios. Results indicate that ALT will increase with the rising air temperature. ALT
may increase by 0.1–0.7 m for the year 2049 and 0.3–1.2 m for the year 2099. The average increment of ALT is 0.8 m with the
largest increment of 1.2 m under the A1F1 scenario and 0.4 m with the largest increment of 0.6 m under the B1 scenario during
the twenty-first century. ALT changes significantly in sporadic permafrost regions, while in the continuous permafrost regions
of the inland plateau ALT change is relatively smaller. The largest increment of ALT occurs in the northeastern and southwestern
plateaus under both scenarios because of higher ground temperatures and lower soil moisture content in these regions. 相似文献
6.
Hongchang Hu Genxu Wang Guangsheng Liu Taibing Li Dongxing Ren Yibo Wang Huiyan Cheng Junfeng Wang 《Environmental Geology》2009,57(6):1391-1397
The alpine ecosystem is very sensitive to environmental change due to global and local disturbances. The alpine ecosystem
degradation, characterized by reducing vegetation coverage or biomass, has been occurring in the Qinghai–Tibet Plateau, which
alters local energy balance, and water and biochemical cycles. However, detailed characterization of the ecosystem degradation
effect is lack in literature. In this study, the impact of alpine ecosystem degradation on soil temperature for seasonal frozen
soil and permafrost are examined. The vegetation coverage is used to indicate the degree of ecosystems degradation. Daily
soil temperature is monitored at different depths for different vegetation coverage, for both permafrost and seasonal frozen
soils. Results show that under the insulating effort of the vegetation, the freezing and thawing process become quicker and
steeper, and the start of the freezing and thawing process moves up due to the insulating effort of the vegetation. The influence
of vegetation coverage on the freezing process is more evident than the thawing process; with the decrease of vegetation coverage,
the integral of frozen depth increases for seasonal frozen soil, but is vice versa for permafrost. 相似文献
7.
Wang Zengru Yang Guojing Yi Shuhua Wu Zhen Guan Jianyue He Xiaobo Ye Baisheng 《Environmental Earth Sciences》2012,66(3):985-991
The effects of the depth of the active layer of permafrost on aboveground vegetation in semi-arid and semi-humid regions of the Qinghai–Tibetan Plateau were studied. The depth of active permafrost was measured and aboveground vegetation recorded. Differences in correspondence between permafrost depth and aboveground vegetation in semi-arid and semi-humid regions were analyzed. Vegetation cover and biomass were well correlated with permafrost depth in both semi-arid and semi-humid regions, but the correlation coefficient in the semi-arid region was larger than in the semi-humid region. With the increase in permafrost depth, vegetation cover and biomass decreased in both regions. Species richness and diversity decreased with increasing depth of permafrost in the semi-arid region. In the semi-humid region, these at first increased and then decreased as permafrost depth increased. It seems likely that vegetation on the Qinghai–Tibetan Plateau will degenerate to different degrees due to permafrost depth increasing as a result of climatic warming. The influence would be especially remarkable in the semi-arid region. 相似文献
8.
Using surface soil daily minimum temperature from 845 meteorological stations across China, the long-term (1971-2000) mean and spatial distribution of the near-surface soil freezing days were estimated with annual values of the number of near surface soil freezing days. The time series for the number of freezing days were constructed and compared with air temperatures in the same period.Resultsshowed that long term mean value in the number of the near surface soil freezing days increased with the increasing latitudes and altitudes over China. Near-surface soils were frozen for more than 200 days in the Qinghai Tibet Plateau, northern Xinjiang and northeast of China. The boundaries of permafrost zones coincide with the contour of (220±10) days of near-surface soil freezing. Using the mean number of 15 days of near-surface soil freezing as criterion, we found that the southern boundary of seasonally frozen ground is around the 25°N line, and the regions south of 22°N are essentially unfrozen regions. The time series of the number of freezing days showed a significant linear trend with change with a slope of -0.22days/year over a period from 1956 through 2006. After the 1990s, the linear slope was up to -1.02 days / year, indicating that the rate of decrease in the number of near-surface soil freezing days has accelerated. Changes in the number of near surface soil freezing were in a negative correlation with air temperature, i.e., the number of near-surface soil freezing days decreases with increase in air temperature.Backgroundcolor represents the contour values of the departure of near-surface soil freezing days from the 1971-2000 mean; Black dashed line is the boundary of permafrost regions, red dashed line is the boundary between frozen and unfrozen ground regions in China 相似文献
9.
《Geomechanics and Geoengineering》2013,8(2):119-127
Widespread warm permafrost with a high ice content is a key problem for the roadbed stability of the Qinghai–Tibet Railway. A new approach is proposed to alleviate the effect of global warming and engineering construction on permafrost by cooling the roadbed and positively protecting the permafrost. Measures for cooling the roadbed by adjusting solar radiation, conduction, and convection are studied and applied to prevent ground ice from thawing and to ensure roadbed stability in permafrost regions. The results of monitoring permafrost embankments at Beiluhe and along the Qinghai–Tibet Railway show that the measures adopted for cooling the roadbed are very effective in raising permafrost table and reducing the soil temperature. 相似文献
10.
路基施工对青藏高原多年冻土的影响 总被引：2，自引：2，他引：0
青藏高原上施工会扰动其下多年冻土的存在状态. 近些年来, 高原上相继修建的大量的线性工程, 这些大型工程的建设必将进行多年冻土区的开挖和夯填, 从而会引起下伏多年冻土的结构发生很大变化. 研究了路基施工对青藏高原多年冻土的影响, 并以青藏铁路、青藏公路沿线典型实例进行分析. 结果表明: 开挖施工扰动最大, 可引起斜坡失稳滑塌、地表积水和热融湖塘等;填土路堤会引起其下伏多年冻土升温, 路基两侧形成的小气候往往起着提高地面温度的作用;挡水、排水设施施工也会导致多年冻土上限下降, 地表沉陷. 可见, 填土路基、开挖、地表工程扰动都会导致多年冻土发生变化, 这些冻土变化对路基稳定必将构成威胁. 相似文献
11.
青藏工程走廊冻土环境工程地质区划及评价 总被引：2，自引：0，他引：2
文章采取层次分析和综合评判的三级区划方法,分别考虑冻土的类型、热稳定性和含冰（水）量,将西大滩至安多间的青藏工程走廊划分为3个工程地质区、20个亚区和51个地段,按区（段）简要评价了冻土工程地质条件和寒区环境.文章对青藏工程走廊进行了较全面的冻土工程和寒区环境工程地质综合评价,能为工程设计、施工和运行维护、融冻灾害整治和环境管理提供科学依据. 相似文献
12.
13.
2009年10月在西安召开第八届国际冻土工程会议, 就冻土地区工程设计与建设、季节冻土区工程冻害防治、冻土物理力学特性、 模型发展及其应用、寒区气候、环境及冷生变化、多年冻土水文学、寒区水资源和土地应用等主要议题进行了广泛交流, 报告了近年来冻土工程与环境研究方面的一些新进展. 从冻土工程设计、施工和评价、普通冻土研究、冻土的物理力学性质、冻土模型发展及应用、 气候变化及冰冻圈环境等方面对该次会议交流的成果进行了总结. 与会研究者认为今后的研究一方面要加强理论研究、工程措施机理研究;另一方面要加强寒区环境对气候变化的响应及反馈、以及环境变化与冻土工程措施之间的相互作用研究. 相似文献
14.
多年冻土地下冰作为一种特殊的存在形式, 对高原生态、 冻土环境以及冻土工程建设等都有深刻影响, 但是目前对于青藏高原地下冰储量的研究很少。以祁连山中东部大通河源区为例, 基于源区地貌分类、 冻土分布等研究, 利用源区多年冻土钻孔数据和公路地质勘测资料, 在水平和垂直两个方向上估算了多年冻土层地下冰储量。计算表明： 大通河源区多年冻土层2.5~10.0 m深度范围内地下冰总储量为（11.70±7.24） km3, 单位体积含冰量为（0.396±0.245） m3。其中冰缘作用丘陵和冰缘湖沼平原等地貌区含冰量较高, 而冰缘作用台地、 冲积洪积平原则含冰量较低。在垂向上多年冻土上限附近含冰量最高, 并随深度增大而缓慢减小。随着未来气候变暖、 多年冻土退化以及环境变化, 准确把握多年冻土区地下冰储量和分布特点对生态、 水文地质、 地质灾害预估、 冻土工程建设具有深远意义。 相似文献
15.
Lihui Luo Wei Ma Wenzhi Zhao Yanli Zhuang Zhongqiong Zhang Mingyi Zhang Di Ma Qingguo Zhou 《Landslides》2018,15(11):2161-2172
Thermal infrared remote sensing technology based on unmanned aerial vehicle (UAV) was applied to estimate the spatial distribution of ground surface temperatures on permafrost slopes and evaluate the thermal influence of nearby engineering infrastructure. This paper presents a method that uses a miniature UAV with a thermal infrared sensor to collect thermal images with high temporal–spatial resolution. Moreover, spatial analysis is used to effectively evaluate the relationship between engineering infrastructure and permafrost slopes in the Qinghai–Tibet Engineering Corridor (QTEC), China. To test the method, aerial measurements were collected from 11:00 to 17:00 in July and August of 2017 at two permafrost slopes along the QTEC, where the Qinghai–Tibet Highway (QTH), Qinghai–Tibet Railway (QTR), and electric towers were built on permafrost slopes. The differences of ground surface temperature between the highway and the surrounding soil were largest at 11:00 and 17:00; the differences were smaller at noon to approximately 15:00 when the difference was minimal, and the differences began to increase after 15:00. The distances of the thermal influence of the highway, railway, and electric towers on the surrounding permafrost slopes are approximately 12–14, 8–10, and 2–4 m, respectively. The results indicate that the degree of influence of engineering structures on permafrost slopes is as follows: QTH?>?QTR?>?electric towers. This study is the first to use UAV-based thermal infrared remote sensing to evaluate the thermal dynamics of permafrost slopes along the QTEC. These results may provide new insights into the future design, construction, and maintenance of engineering structures on permafrost slopes. 相似文献
16.
中国-俄罗斯原油管道工程(简称中俄原油管道)规划全长1,035 km,中国境内段965 km,俄罗斯境内段70 km。中俄原油管道(漠河—大庆段)穿越约500 km多年冻土区,沿途地形起伏,水系和沼泽发育,冻土工程地质条件复杂,影响因素多样。提出以管道地基土的最大融沉变形量为评价准则,以多年冻土的年平均地温和含冰量为评价指标,对多年冻土进行工程分类,并依据分类结果进行评价。依据计算结果以-1.0℃和-2.0℃对中俄原油管道沿线多年冻土进行冻土工程分类。具体分为:稳定型、过渡型、高温不稳定型(-1.0~-2.0℃)以及极高温极不稳定型(≥-1.0℃)。分别对应良好、较好、不良以及极差评价结果,并以此为基准选择传统埋设、埋设、埋设+换填、埋设+换填+隔热或架设等管基设计原则。对管道沿线约430 km多年冻土区进行了详细和逐段的评价。评价结果表明评价指标简单、实用,评价结果合理、恰当,可推荐在其它多年冻土区类似管道工程中使用。 相似文献
17.
应用冷却路基原理建设青藏铁路 总被引：9，自引：6，他引：3
More than half of the total length of the Qinghai-Tibet Railroad (QTR) traverses warm (0 to-1℃) permafrost areas, and about 40% of its total length is in ice-rich permafrost areas. Thc construction of the QTR also must consider the impacts of climatic warming along the QTR during the next 50～100 years. The latest projection indicates a warming of 2.2 to 2.6℃ on the Qinghai-Tibet Plateau (QTP) by the year 2050. Therefore, the key to the successful construction of the QTR is to protect permafrost from being thawed. Although railroad construction in permafrost areas has had a history of more than 100 years, the troubled sections of the railroads in permafrost areas have been greater than 30% of their total length. Based on the experiences and lessons learned from the road construction in permafrost areas, both in China and abroad, the author proposes that the principle of “active cooling” of railroad roadbed by lowering permafrost temperatures should be used in designing QTR, rather than that of “passive protection” of permafrost through increasing thermal resistance of roadway, such as increasing fill thickness and/or using insulative materials. This is especially important for the road sections in warm, ice-rich permafrost. In addition, this paper proposes several methods for “cooling the roadbcd” by controlling radiation, convection and conduction through modifying roadway structure and using different fill materials. 相似文献
18.
青藏500kV直流联网工程穿越青藏高原多年冻土区,冻土特有的工程问题将对工程设计、施工和安全运营产生重要影响。由于输电线路属于点线结构的工程特点,即塔基的稳定性关系到整条线路的稳定性,而塔基点位又具有一定的可调性,因此,多年冻土及厚层地下冰的分布特征对于输电线路的选线、选位较其他线性工程更具重要意义。本文主要在输电线路沿线冻土分布的基础上,重点对微地貌条件下冻土和厚层地下冰的分布发育规律进行了分析和研究。并在此基础上,结合输电线路工程特点,就线路的选线选位的原则进行了分析和确定。 相似文献
19.
The permafrost on the Qinghai-Tibet Plateau(QTP) is unstable and sensitive to thermal disturbance due to the combined influences of anthropogenic forcing and global warming on the unique environmental background for permafrost development and preservation. Observations in about 40 years show natural and engineering environments of permafrost region along Qinghai-Tibet Highway(QTH)have changed significantly. The change of permafrost environments on the plateau will result in the remarkable shifts of physical geography and engineering geological environments. In addition, permafrost on the QTP responses actively and feedbacks to global climatic changes significantly. The study of permafrost on the plateau is no less important than the Arctic and Antarctic, and also provide a valuable linkage of climatic and environmental change studies between the other two poles. As the development of the plateau and adjacent areas in large scale is eminent, permafrost as the most important natural environmental factor, its stability and possible changes are extremely important in regional economical development. Therefore, the prediction of these changes and reasonable assessment of permafrost engineering conditions on the plateau based on permafrost monitoring are indispensable for the healthy and sustainable economical development in these regions. 相似文献