多年冻土地基正温输气管道地温场实测及分析     

施瑞  徐震  刘德仁  蒋代军  王旭  胡渊  温智 《冰川冻土》2019,41(4):865-874

我国有多条油气管道位于多年冻土地区,工程问题层出不穷。因输送介质处于正温状态,其所释放热量对管道周围冻土冻融过程有极大影响。为阐明正温管道对多年冻土温度场及冻融特征的影响,基于西部某多年冻土区正温输气管道现场实验,对管道地基温度场进行了为期1年的现场实测。数据分析表明,多年冻土天然上限为1.5~2.0 m;土体融化期及冻结期分别为6-10月、11-次年5月;监测段多年冻土热量收支基本平衡,属于不稳定冻土,在外界热扰动下极易退化;正温输气管道的存在引起了多年冻土的退化且对其温度场有很大影响,水平方向影响范围约1.5 m,管下最大融深可达7.0 m。同时指出了针对处于临界状态的多年冻土,在基于对其全面、深入了解的基础上,越早考虑相关工程建设带来的热扰动对多年冻土的不利影响,则处置难度越低且损失越小。  相似文献   

一种冻土区天然气水合物地球化学勘查新技术——惰性气体氦氖分析     

张富贵  唐瑞玲  周亚龙  张舜尧  孙忠军  王惠艳 《地质学报》2019,93(3):751-761

开发不受沼泽微生物影响的地球化学勘查技术是提高中纬度冻土区天然气水合物探井预测成功率的重要课题之一。本文选择在祁连山聚乎更天然气水合物已知区进行惰性气体勘查技术实验,研究了氦氖的测试方法,实验区为高寒沼泽景观,面积150km~2,采样密度2点/km~2,采样深度60cm,采集土壤顶空气样品300件和DK-3井岩芯样品400件,应用色谱反吹技术对顶空气样品进行了惰性气体氦氖的分析。结合地质和地球化学勘查成果进行了综合解释,认为惰性气体异常与天然气水合物矿藏关系密切,与烃类异常浓度范围一致,为顶部异常模式。实验区天然气水合物矿藏11个水合物发现井有10个位于He、Ne异常内,1个井位于异常外。分析了天然气水合物岩芯顶空气轻烃和氦氖指标的垂向分布特征,提出了天然气水合物矿藏上方土壤惰性气体的地气迁移机理。研究区近地表氦氖异常源于深部水合物矿藏和断裂构造,不受沼泽微生物的影响,是冻土区天然气水合物勘查的一种有效技术。  相似文献   

Energy flux partitioning and evapotranspiration in a sub‐alpine spruce forest ecosystem          下载免费PDF全文

Zhu Gaofeng  Lu Ling  Su Yonghong  Wang Xufeng  Cui Xia  Ma Jinzhu  He Jianhua  Zhang Kun  Li Changbin 《水文研究》2014,28(19):5093-5104

In this study, we examined the year 2011 characteristics of energy flux partitioning and evapotranspiration of a sub‐alpine spruce forest underlain by permafrost on the Qinghai–Tibet Plateau (QPT). Energy balance closure on a half‐hourly basis was H + λE = 0.81 × (R_n ? G ? S) + 3.48 (W m^?2) (r² = 0.83, n = 14938), where H, λE, R_n, G and S are the sensible heat, latent heat, net radiation, soil heat and air‐column heat storage fluxes, respectively. Maximum H was higher than maximum λE, and H dominated the energy budget at midday during the whole year, even in summer time. However, the rainfall events significantly affected energy flux partitioning and evapotranspiration. The mean value of evaporative fraction (Λ = λE/(λE + H)) during the growth period on zero precipitation days and non‐zero precipitation days was 0.40 and 0.61, respectively. The mean daily evapotranspiration of this sub‐alpine forest during summer time was 2.56 mm day^?1. The annual evapotranspiration and sublimation was 417 ± 8 mm year^?1, which was very similar to the annual precipitation of 428 mm. Sublimation accounted for 7.1% (30 ± 2 mm year^?1) of annual evapotranspiration and sublimation, indicating that the sublimation is not negligible in the annual water balance in sub‐alpine forests on the QPT. The low values of the Priestley–Taylor coefficient (α) and the very low value of the decoupling coefficient (Ω) during most of the growing season suggested low soil water content and conservative water loss in this sub‐alpine forest. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

祁连山疏勒河源区冻土退化对土壤微生物生物量碳氮的影响   总被引：2，自引：1，他引：1  

吴明辉  瞿德业  李婷  刘放  高雅月  陈生云  陈拓 《地理科学》2021,41(1):177-186

对青藏高原东北缘祁连山西段疏勒河源区多年冻土区0~50 cm土壤微生物生物量碳氮分布特征及其影响因素进行分析。结果表明:稳定型和极不稳定型多年冻土区0~50 cm土壤中微生物量碳含量范围分别为0.015~0.620 g/kg和0.019~0.411 g/kg,微生物量氮含量范围分别为0.644~12.770 mg/kg和0.207~3.725 mg/kg;土壤微生物量总体呈现出稳定型显著高于极不稳定型多年冻土,表明多年冻土退化（多年冻土由稳定型退化为极不稳定型）对土壤微生物量积累有明显抑制作用。土壤微生物生物量碳占有机碳、微生物生物量氮占全氮的比值在稳定型多年冻土中显著高于极不稳定型,表明多年冻土退化对土壤微生物的矿化能力有明显抑制作用。土壤微生物量及其与土壤养分的比值有显著的剖面变化特征,随土壤深度增加而减小。土壤微生物量碳氮均与土壤温度显著负相关,与地下生物量显著正相关。稳定型多年冻土中,土壤微生物量碳氮与碳氮比正相关、与氧化还原电位负相关;不稳定型多年冻土中,土壤微生物量碳氮与pH正相关。土壤微生物量碳氮与土壤温度和pH在剖面变化上显著相关。逐步回归分析表明驱动微生物生物量碳氮在不同多年冻土类型和土层之间变化的因子是不同的。  相似文献   

近50年来黑龙江省冻土厚度的时空变化特征     

王宁  臧淑英  张丽娟 《地理研究》2018,37(3):622-634

基于MK检验、滑动t检验、EOF分析方法,使用近50年（1961-2012年）黑龙江省32个气象基准台站逐日冻土观测数据、气温观测数据,对黑龙江省冻土厚度时空变化特征进行了分析。结果表明：① 近50年黑龙江省冻土厚度减少了12.86 cm,下降速率为-0.53 cm/a,以2001年为界发生了突变。② 冻土厚度空间分布呈现由北厚南薄格局,中部地区冻土厚度较同纬度其他区域偏低;空间变化呈现南部冻土厚度降低快,北部降低慢,中部与西部、东南部呈相反变化的特征,伊春、铁力、漠河观测点为冻土变化敏感区。③ 气温是影响黑龙江省冻土厚度变化的主要因素,与冻土厚度相关系数为-0.611。本文的主要贡献为揭示了黑龙江省冻土厚度的空间变化特征,为相关研究及各级政府规划提供了依据。  相似文献   

Surface-deformation monitoring in the permafrost regions over the Tibetan Plateau,using Sentinel-1 data     

ZhenMing Wu  Lin Zhao  Lin Liu  Rui Zhu  ZeShen Gao  YongPing Qiao  LiMing Tian  HuaYun Zhou  MeiZhen Xie 《寒旱区科学》2018,10(2):114-125

Differential Interferometric Synthetic Aperture Radar(D-In SAR) has been widely used to measure surface deformation over the Tibetan Plateau. However, the accuracy and applicability of the D-In SAR method are not well estimated due to the lack of in-situ validation. In this paper, we mapped the seasonal and long-term displacement of Tanggula(TGL) and Liangdaohe(LDH) permafrost regions with a stack of Sentinel-1 acquisitions using the Small Baseline Subset In SAR(SBAS-In SAR) method. In the TGL region, with its dry soils and sparse vegetation, the In SAR-derived surface-deformation trend was consistent with ground-based leveling results; long-term changes of the active layer showed a settlement rate of around 1 to 3 mm/a due to the melting of ground ice, indicating a degrading permafrost in this area. Around half of the deformation was picked up on monitoring, in contrast with in-situ measurements in LDH, implying that the D-In SAR method remarkably underestimated the surface-deformation. This phenomenon may be induced by the large soil-water content, high vegetation coverage, or a combination of these two factors in this region. This study demonstrates that surface deformation could be mapped accurately for a specific region with Sentinel-1 C-band data, such as in the TGL region.Moreover, although the D-In SAR technology provides an efficient solution for broad surface-deformation monitoring in permafrost regions, it shows a poor performance in the region with high soil-water content and dense vegetation coverage.  相似文献   

Evolution and changes of permafrost on the Qinghai-Tibet Plateau during the Late Quaternary     

XiaoLi Chang  HuiJun Jin  RuiXia He  LanZhi L&#;  Stuart A. Harris 《寒旱区科学》2017,9(1):1-19

Due to the uplift of Qinghai-Tibet Plateau(QTP), the cryosphere gradually developed on the higher mountain summits after the Neocene, becoming widespread during the Late Quaternary. During this time, permafrost on the QTP experienced repeated expansion and degradation. Based on the remains and cross-correlation with other proxy records such as those from glacial landforms, ice-core and paleogeography, the evolution and changes of permafrost and environmental changes on the QTP during the past 150,000 years were deduced and are presented in this paper. At least four obvious cycles of the extensive and intensive development, expansion and decay of permafrost occurred during the periods of 150–130, 80–50, 30–14 and after 10.8 ka B.P.. During the Holocene, fluctuating climatic environments affected the permafrost on the QTP, and the peripheral mountains experienced six periods of discernible permafrost changes:(1) Stable development of permafrost in the early Holocene(10.8 to 8.5–7.0 ka B.P.);(2) Intensive permafrost degradation during the Holocene Megathermal Period(HMP, from 8.5–7.0 to 4.0–3.0 ka B.P.);(3) Permafrost expansion during the early Neoglacial period(ca. 4,000–3,000 to 1,000 a B.P.);(4) Relative degradation during the Medieval Warm Period(MWP, from 1,000 to 500 a B.P.);(5) Expansion of permafrost during the Little Ice Age(LIA, from 500 to 100 a B.P.);(6) Observed and predicted degradation of permafrost during the 20 th and 21 st century. Each period differed greatly in paleoclimate, paleoenvironment, and permafrost distribution, thickness, areal extent, and ground temperatures, as well as in the development of periglacial phenomena. Statistically, closer dating of the onset permafrost formation, more identification of permafrost remains with richer proxy information about paleoenvironment, and more dating information enable higher resolution for paleo-permafrost reconstruction. Based on the scenarios of persistent climate warming of 2.2～2.6 °C in the next 50 years, and in combination of the monitored trends of climate and permafrost changes, and model predictions suggest an accelerated regional degradation of plateau permafrost. Therefore, during the first half of the 21 st century, profound changes in the stability of alpine ecosystems and hydro(geo)logical environments in the source regions of the Yangtze and Yellow rivers may occur. The foundation stability of key engineering infrastructures and sustainable economic development in cold regions on the QTP may be affected.  相似文献   

青藏铁路建设环境的"三大难题"     

许兆义  李宁  魏静 《吉林大学学报(地球科学版)》2007,37(2):406-410

青藏铁路是世界上第一条跨越高原多年冻土区的铁路,工程建设环境面临多年冻土、高寒缺氧、生态脆弱的“三大难题”,比国内外其他多年冻土工程建设更艰巨和困难。由于青藏铁路建设环境的特殊性与复杂性,设计和建设中采取了多种保护冻土的有效措施、高原劳动卫生和劳动保护措施及生态环境保护措施及污染防治措施,各项措施在青藏铁路的建设和运营中显示出了良好的效果。  相似文献   

高原多年冻土地区公路修筑技术研究的回顾与展望   总被引：11，自引：6，他引：5  

章金钊  武敬民 《冰川冻土》1999,21(2):187-191

通过大量的研究课题实例,回顾了高原多年冻土地区公路修筑技术研究的各个历史阶段,综述了公路修筑技术的研究内容和成果。高含冰量冻土分布规律及工程地质研究、冻土路基设计与冻土路基变形规律研究及保持冻土路基稳定性的路基设计原则和工程措施研究、路面修筑技术研究、桥涵基础研究等。随着高原多年冻土地区公路路面等级的提高和路面使用时间的延续及人为因素的不良影响,高原多年冻土地区的公路路基、路面和桥涵等出现了一些新  相似文献   

多年冻土区青藏铁路列车荷载作用下路基振动响应研究          下载免费PDF全文

董连成  徐禛  师黎静  胡新福  高德领 《地震工程学报》2018,40(6):1153-1160

针对多年冻土区青藏铁路列车荷载振动作用下的动稳定性,通过对北麓河和二道沟三个典型铁路路基横断面振动响应的二分量加速度观测,对比分析客运列车和货运列车引起的路基振动特性和衰减规律,研究不同防护形式路基的列车振动响应。结果表明,路基上的振动作用主要集中在40～80Hz频率范围内;防护形式对路基的列车动力响应有明显影响,热棒加碎石路基动力响应最小,其次为碎石防护路基,未采取任何防护的路基铁轨上的动力响应最大,建议对未采取防护的路基进行防护。分析结论为青藏铁路列车作用下的路基动稳定性评估提供实测依据,对多年冻土区的路基稳定性研究提供参考。  相似文献