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气温变化对多年冻土斜坡稳定性的影响
引用本文:沈凌铠, 周保, 魏刚, 魏赛拉加, 常文斌, 张明哲, 邢爱国. 气温变化对多年冻土斜坡稳定性的影响——以青海省浅层冻土滑坡为例[J]. 中国地质灾害与防治学报, 2023, 34(1): 8-16. doi: 10.16031/j.cnki.issn.1003-8035.202112025
作者姓名:沈凌铠  周保  魏刚  魏赛拉加  常文斌  张明哲  邢爱国
作者单位:1.上海交通大学船舶海洋与建筑工程学院,上海 200240;; 2.青海省地质环境监测总站,青海西宁 810007;; 3.青海省环境地质勘查局,青海 西宁 810007
基金项目:创新平台建设专项项目(2021-ZJ-T08);基础研究计划项目(2019-ZJ-7053)
摘    要:受气温变化影响,浅层冻土滑坡失稳涉及水分的固液相态转换,是一个复杂的水热力耦合过程。为揭示气温变化对多年冻土斜坡稳定性的影响,基于冻土水热力耦合数值模型,模拟了2020—2024年青海省多年冻土区斜坡水热力演化过程。研究结果表明:水分迁移速率呈周期性变化,每年5—10月活动层融化程度高,总体积含水率变化趋势显著;夏季多年冻土上限以下的高含冰量土层融化产生厚度约15 cm的富水层,孔隙水压难以消散;4年间多年冻土上限下移10.4 cm,导致活动层和富水层的厚度增大,上覆融土下滑力增大、抗滑力减小,土体抗剪强度进一步下降;活动层土体每年产生数厘米冻胀融沉变形,抗剪强度不断劣化,坡脚处最容易形成薄弱带。

关 键 词:活动层   水热力耦合   多年冻土退化   水分迁移   冻胀融沉   浅层冻土滑坡
收稿时间:2021-12-21
修稿时间:2022-04-26

Influence of air temperature change on stability of permafrost slope: A case study of shallow permafrost landslide in Qinghai Province
SHEN Lingkai, ZHOU Bao, WEI Gang, WEI Sailajia, CHANG Wenbin, ZHANG Mingzhe, XING Aiguo. Influence of air temperature change on stability of permafrost slope: A case study of shallow permafrost landslide in Qinghai Province[J]. The Chinese Journal of Geological Hazard and Control, 2023, 34(1): 8-16. doi: 10.16031/j.cnki.issn.1003-8035.202112025
Authors:SHEN Lingkai  ZHOU Bao  WEI Gang  WEI Sailajia  CHANG Wenbin  ZHANG Mingzhe  XING Aiguo
Affiliation:1.School of Naval Architecture, Ocean & Civil Engineering, Shanghai Jiaotong University, Shanghai 200240, China;; 2.Qinghai Geological Environment Monitoring Station, Xining, Qinghai 810007, China;; 3.Qinghai Environmental Geology Exploration Bureau, Xining, Qinghai 810007, China
Abstract:Under the influence of air temperature change, shallow permafrost landslide is a complex thermal-hydro-mechanical coupling process, which involves the transformation of water between solid state and liquid state. To reveal the influence of air temperature change on the shallow permafrost landslide, based on the coupled thermal-hydro-mechanical model for frozen soil, the thermal-hydro-mechanical evolution process of slope in permafrost region from 2020 to 2024 is simulated. The results are as follows: the rate of water migration presents periodic variation. The thawing degree of the active layer from May to October is high, causing the variation trend of total water content significantly. In summer, the thawing of the high ice content layer below the permafrost table forms a water-rich layer of 15 cm thickness approximately, causing excess pore water pressure difficult to dissipate. The permafrost table will decline by 10.4 cm in 4 years, and the thickness of the active layer and water-rich layer increased. As a result, the sliding force of the overlying thawed soil increases, the sliding resistance decreases, and the shear strength of the soil further decreases. Several centimeters displacement of frost heave and thaw settlement occurs in the active layer per year, shear strength deteriorates continuously, and the weak zone is easiest formed at slope toe.
Keywords:active layer  coupling of seepage-temperature-stress  permafrost degradation  water migration  frost heave and thaw settlement  shallow permafrost landslide
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